const pptxgen = require("pptxgenjs");

const pres = new pptxgen();
pres.layout = "LAYOUT_WIDE"; // 13.3" x 7.5"
pres.title = "General Medicine Drug Doses - Quick Reference";

// ─── COLOUR PALETTE ───────────────────────────────────────────────────────────
const C = {
  navy:    "0D1B2A",
  teal:    "1B6CA8",
  tealLt:  "2390D1",
  green:   "1A7A4A",
  greenLt: "22A35F",
  red:     "B32A2A",
  redLt:   "D63B3B",
  amber:   "B56A00",
  amberLt: "E08C1A",
  purple:  "5C2D91",
  purpleLt:"7B3FB8",
  slate:   "374151",
  slateL:  "6B7280",
  offWhite:"F5F7FA",
  white:   "FFFFFF",
  rowAlt:  "EEF3FA",
  rowBase: "FFFFFF",
  headerBg:"1B4F72",
};

// ─── HELPERS ──────────────────────────────────────────────────────────────────
function hdrRect(slide, x, y, w, h, color) {
  slide.addShape(pres.ShapeType.rect, { x, y, w, h, fill: { color }, line: { color, width: 0 } });
}
function cell(slide, text, x, y, w, h, opts = {}) {
  const {
    bg = C.white, color = C.slate, bold = false, sz = 7.5,
    align = "left", valign = "middle", border = true, italic = false
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    slide.addShape(pres.ShapeType.rect, {
      x, y, w, h,
      fill: { color: bg },
      line: border ? { color: "D1D5DB", width: 0.5 } : { color: bg, width: 0 },
    });
  }
  slide.addText(text, {
    x, y, w, h,
    fontSize: sz, fontFace: "Calibri", color,
    bold, italic, align, valign,
    margin: 3, wrap: true,
  });
}

function sectionLabel(slide, text, x, y, w, color) {
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    x, y, w, h: 0.26,
    fontSize: 8.5, fontFace: "Calibri", color: C.white,
    bold: true, align: "center", valign: "middle", margin: 2,
  });
}

// Column widths for drug tables: Drug | Dose | Route/Freq | Indication | Notes
const CW = [1.75, 2.0, 1.15, 1.8, 1.8]; // total ~8.5"
function colX(startX, colIdx) {
  let x = startX;
  for (let i = 0; i < colIdx; i++) x += CW[i];
  return x;
}

function tableHeader(slide, startX, y, cols) {
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    const x = colX(startX, i);
    slide.addShape(pres.ShapeType.rect, { x, y, w: CW[i], h: 0.24, fill: { color: C.headerBg }, line: { color: C.headerBg, width: 0 } });
    slide.addText(label, { x, y, w: CW[i], h: 0.24, fontSize: 7, fontFace: "Calibri", color: C.white, bold: true, align: "center", valign: "middle", margin: 1 });
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}

function tableRow(slide, rowData, startX, y, rowIndex) {
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    const x = colX(startX, i);
    const isNote = i === 4;
    cell(slide, text, x, y, CW[i], 0.235, { bg, sz: isNote ? 6.8 : 7.5, italic: isNote, color: isNote ? C.slateL : C.slate });
  });
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 1 - COVER
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  // Full background
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 7.5, fill: { color: C.navy }, line: { color: C.navy, width: 0 } });
  // Accent bar
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 0.08, fill: { color: C.tealLt }, line: { color: C.tealLt, width: 0 } });
  s.addShape(pres.ShapeType.rect, { x: 0, y: 7.42, w: 13.3, h: 0.08, fill: { color: C.tealLt }, line: { color: C.tealLt, width: 0 } });

  s.addText("General Medicine", { x: 1, y: 1.6, w: 11.3, h: 0.8, fontSize: 40, fontFace: "Calibri", color: C.tealLt, bold: true, align: "center" });
  s.addText("Common Drug Doses", { x: 1, y: 2.45, w: 11.3, h: 0.8, fontSize: 46, fontFace: "Calibri", color: C.white, bold: true, align: "center" });
  s.addText("QUICK REFERENCE CHEAT SHEET", { x: 1, y: 3.3, w: 11.3, h: 0.45, fontSize: 16, fontFace: "Calibri", color: C.tealLt, bold: true, align: "center", charSpacing: 4 });

  // Pill icons as coloured rectangles
  const tags = [
    ["CARDIOVASCULAR", C.teal],
    ["RESPIRATORY", C.green],
    ["NEUROLOGY", C.purple],
    ["ENDOCRINE", C.amber],
    ["ANTIBIOTICS", C.red],
    ["EMERGENCY", "8B0000"],
  ];
  const tagW = 1.7, tagGap = 0.12;
  const totalW = tags.length * tagW + (tags.length - 1) * tagGap;
  const startX = (13.3 - totalW) / 2;
  tags.forEach(([label, color], i) => {
    const x = startX + i * (tagW + tagGap);
    s.addShape(pres.ShapeType.roundRect, { x, y: 4.2, w: tagW, h: 0.32, fill: { color }, line: { color, width: 0 }, rectRadius: 0.06 });
    s.addText(label, { x, y: 4.2, w: tagW, h: 0.32, fontSize: 7.5, fontFace: "Calibri", color: C.white, bold: true, align: "center", valign: "middle" });
  });

  s.addText("For educational use only. Always verify doses with current formulary and patient-specific factors.", {
    x: 1, y: 6.8, w: 11.3, h: 0.4, fontSize: 8, fontFace: "Calibri", color: "6B7280", italic: true, align: "center"
  });
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 2 - CARDIOVASCULAR DRUGS
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 7.5, fill: { color: C.offWhite }, line: { color: C.offWhite, width: 0 } });

  // Title bar
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 0.5, fill: { color: C.teal }, line: { color: C.teal, width: 0 } });
  s.addText("CARDIOVASCULAR DRUGS", { x: 0.2, y: 0, w: 10, h: 0.5, fontSize: 16, fontFace: "Calibri", color: C.white, bold: true, valign: "middle" });
  s.addText("Slide 2 of 6", { x: 10.3, y: 0, w: 2.8, h: 0.5, fontSize: 9, fontFace: "Calibri", color: "B3CFED", align: "right", valign: "middle" });

  // LEFT COLUMN - ACE Inhibitors / ARBs / ARNIs
  const LX = 0.15;
  const cols = ["Drug", "Standard Dose", "Route/Freq", "Indication", "Key Notes"];

  // Section: ACE Inhibitors
  sectionLabel(s, "ACE INHIBITORS / ARBs / ARNI", LX, 0.56, 8.55, C.teal);
  tableHeader(s, LX, 0.82, cols);
  [
    ["Ramipril", "2.5–10 mg", "PO OD", "HTN, HF, post-MI, DM nephroprotection", "⚠ Hold if K+>5.5 or AKI. Dry cough 10%"],
    ["Enalapril", "2.5–20 mg", "PO BD", "HTN, HFrEF", "Monitor U&E/K+ at 1-2 weeks"],
    ["Lisinopril", "5–40 mg", "PO OD", "HTN, HF, DM", "Avoid in pregnancy (all trimesters)"],
    ["Losartan", "25–100 mg", "PO OD", "HTN, HF (ACEi intolerant), DM nephropathy", "Less cough vs ACEi. Same K+/renal risks"],
    ["Sacubitril/Valsartan", "24/26–97/103 mg", "PO BD", "HFrEF (replace ACEi/ARB)", "Washout 36h from ACEi. Superior mortality benefit"],
  ].forEach((row, i) => tableRow(s, row, LX, 1.06 + i * 0.235, i));

  // Section: Beta-Blockers
  sectionLabel(s, "BETA-BLOCKERS", LX, 2.28, 8.55, C.tealLt);
  tableHeader(s, LX, 2.54, cols);
  [
    ["Bisoprolol", "1.25–10 mg", "PO OD", "HFrEF, HTN, AF rate control", "Titrate slowly in HF. Avoid in asthma/decompensated HF"],
    ["Carvedilol", "3.125–25 mg", "PO BD", "HFrEF, post-MI", "Non-selective; has alpha-blocking effect"],
    ["Metoprolol (succinate)", "12.5–200 mg", "PO OD", "HF, HTN, AF, angina", "Cardioselective. MERIT-HF trial"],
    ["Atenolol", "25–100 mg", "PO OD", "HTN, angina", "Avoid in HF/COPD. Less CNS penetration"],
    ["Propranolol", "10–80 mg", "PO BD–TDS", "Anxiety, thyrotoxicosis, migraine Px, essential tremor", "Non-selective. Crosses BBB. Masks hypoglycaemia"],
  ].forEach((row, i) => tableRow(s, row, LX, 2.78 + i * 0.235, i));

  // Section: Calcium Channel Blockers
  sectionLabel(s, "CALCIUM CHANNEL BLOCKERS", LX, 3.98, 8.55, "145A6E");
  tableHeader(s, LX, 4.24, cols);
  [
    ["Amlodipine", "5–10 mg", "PO OD", "HTN, stable angina", "Peripheral oedema common. Safe in HFpEF"],
    ["Diltiazem", "60–120 mg", "PO TDS (or SR BD)", "AF rate control, angina, HTN", "⚠ Avoid with beta-blocker (heart block)"],
    ["Verapamil", "40–120 mg", "PO TDS", "AF rate control, SVT, cluster headache Px", "⚠ Avoid with beta-blocker. Constipation"],
    ["Nifedipine LA", "30–60 mg", "PO OD", "HTN, Raynaud's, angina", "Do NOT use short-acting for HTN (reflex tachycardia)"],
  ].forEach((row, i) => tableRow(s, row, LX, 4.48 + i * 0.235, i));

  // Section: Diuretics  (right column area, placed below)
  sectionLabel(s, "DIURETICS", LX, 5.43, 8.55, C.slate);
  tableHeader(s, LX, 5.69, cols);
  [
    ["Furosemide", "20–80 mg (up to 500 mg IV in resistant)", "PO/IV OD–BD", "Acute pulmonary oedema, HF, oedema", "Monitor K+/Na+. Ototoxic at high IV doses"],
    ["Spironolactone", "12.5–50 mg", "PO OD", "HFrEF, hyperaldosteronism, ascites", "⚠ K+-sparing. Avoid if K+>5.0. Gynaecomastia"],
    ["Eplerenone", "25–50 mg", "PO OD", "Post-MI HF, HFrEF", "Fewer endocrine SE than spironolactone"],
    ["Indapamide", "1.5 mg SR or 2.5 mg", "PO OD", "HTN (thiazide-like)", "Less metabolic disturbance than HCTZ"],
  ].forEach((row, i) => tableRow(s, row, LX, 5.93 + i * 0.235, i));

  // Footer
  s.addText("⚠ Doses are for average adults with normal renal/hepatic function. Always adjust for patient factors.", {
    x: 0.15, y: 7.3, w: 13, h: 0.18, fontSize: 6.5, fontFace: "Calibri", color: C.redLt, italic: true
  });
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 3 - CARDIOVASCULAR CONT. (Anticoagulants, Antiplatelets, Statins, Anti-arrhythmics)
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 7.5, fill: { color: C.offWhite }, line: { color: C.offWhite, width: 0 } });
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 0.5, fill: { color: C.teal }, line: { color: C.teal, width: 0 } });
  s.addText("CARDIOVASCULAR DRUGS (cont.) — Antiplatelets, Anticoagulants, Statins, Anti-arrhythmics", { x: 0.2, y: 0, w: 12, h: 0.5, fontSize: 13, fontFace: "Calibri", color: C.white, bold: true, valign: "middle" });
  s.addText("Slide 3 of 6", { x: 10.3, y: 0, w: 2.8, h: 0.5, fontSize: 9, fontFace: "Calibri", color: "B3CFED", align: "right", valign: "middle" });

  const LX = 0.15;
  const cols = ["Drug", "Standard Dose", "Route/Freq", "Indication", "Key Notes"];

  sectionLabel(s, "ANTIPLATELETS", LX, 0.56, 8.55, C.red);
  tableHeader(s, LX, 0.82, cols);
  [
    ["Aspirin", "75 mg (maintenance) / 300 mg loading", "PO OD", "ACS secondary prevention, AF (rare now), stroke", "Loading 300 mg for ACS. GI protection with PPI"],
    ["Clopidogrel", "75 mg (maint) / 300–600 mg load", "PO OD", "ACS, post-PCI, stroke/TIA (non-cardioembolic)", "Prodrug – CYP2C19 metabolism. Avoid with PPIs if possible"],
    ["Ticagrelor", "90 mg BD (maint) / 180 mg load", "PO BD", "ACS (preferred over clopidogrel for ACS)", "Dyspnoea SE. Reversible binding (holds advantage over clopidogrel in surgery)"],
    ["Prasugrel", "5–10 mg OD (10 mg if >60 kg)", "PO OD", "ACS with PCI (especially STEMI)", "⚠ Contraindicated if prior TIA/stroke, age ≥75, weight <60 kg"],
    ["Dipyridamole MR", "200 mg BD", "PO BD", "Stroke/TIA prevention (with aspirin)", "Headache common at start. Avoid in unstable angina"],
  ].forEach((row, i) => tableRow(s, row, LX, 1.06 + i * 0.235, i));

  sectionLabel(s, "ANTICOAGULANTS", LX, 2.28, 8.55, "7B0D1E");
  tableHeader(s, LX, 2.54, cols);
  [
    ["Warfarin", "Dose variable (INR guided, start 5–10 mg)", "PO OD", "AF, mechanical valves, VTE treatment/Px", "Target INR 2–3 (AF/VTE); 2.5–3.5 (metallic valves). Many interactions"],
    ["Apixaban", "5 mg BD (2.5 mg BD if ≥2 of: age≥80, wt≤60kg, Cr≥133)", "PO BD", "AF, VTE Tx/Px", "Hold if eGFR <15. No routine monitoring. Less bleeding vs warfarin"],
    ["Rivaroxaban", "20 mg OD (with evening meal) for AF; 15 mg BD x21d then 20 mg for VTE", "PO OD/BD", "AF, DVT/PE treatment and prevention", "Renal dose adj if eGFR <50. Take with food"],
    ["Edoxaban", "60 mg OD (30 mg if eGFR 15-50 or wt≤60 kg)", "PO OD", "AF, VTE", "Reduce dose in renal impairment or low weight"],
    ["LMWH (Enoxaparin)", "Treatment: 1 mg/kg SC BD. Prophylaxis: 40 mg SC OD", "SC", "DVT/PE treatment, surgical prophylaxis, ACS bridging", "Reduce dose if eGFR <30. Monitor anti-Xa if obese/pregnant/renal"],
    ["UFH (Unfractionated)", "IV 5000 U bolus then 18 U/kg/h infusion (aPTT guided)", "IV infusion", "STEMI (PCI), PE with instability, reversal with protamine needed", "Reverse with protamine sulphate. Short half-life – useful peri-op"],
  ].forEach((row, i) => tableRow(s, row, LX, 2.78 + i * 0.235, i));

  sectionLabel(s, "STATINS", LX, 4.22, 8.55, C.purple);
  tableHeader(s, LX, 4.48, cols);
  [
    ["Atorvastatin", "10–80 mg", "PO nocte", "CVD primary/secondary prevention, HF, post-ACS (80 mg)", "High-intensity. Most commonly used. Take at night"],
    ["Rosuvastatin", "5–40 mg", "PO OD", "High CVD risk, familial hypercholesterolaemia", "High-intensity. Fewer myopathy interactions vs atorvastatin"],
    ["Simvastatin", "10–40 mg (max 80 mg – avoid due to myopathy risk)", "PO nocte", "CVD prevention", "⚠ Multiple drug interactions (diltiazem, amiodarone). Now rarely first-line"],
  ].forEach((row, i) => tableRow(s, row, LX, 4.72 + i * 0.235, i));

  sectionLabel(s, "ANTI-ARRHYTHMICS", LX, 5.42, 8.55, "4B2067");
  tableHeader(s, LX, 5.68, cols);
  [
    ["Amiodarone", "200 mg TDS x1 wk → 200 mg BD x1 wk → 200 mg OD. IV: 300 mg over 20–60 min", "PO/IV", "AF, VT, VF (cardiac arrest)", "⚠ Thyroid, pulmonary, hepatic toxicity. TFTs/LFTs/CXR every 6 months. Photosensitivity"],
    ["Digoxin", "62.5–250 mcg OD (loading: 250–500 mcg, then 125–250 mcg)", "PO OD", "AF rate control (especially HF), HF with AF", "Narrow TI. Toxic if K+ low. Level 1–2 nmol/L. Bradycardia, N&V, visual changes"],
    ["Flecainide", "50–150 mg BD", "PO BD", "AF rhythm control, SVT", "⚠ Avoid post-MI or structural heart disease (pro-arrhythmic). Pill-in-pocket for paroxysmal AF"],
    ["Adenosine", "6 mg IV rapid bolus → 12 mg → 12 mg (with flush)", "IV rapid bolus", "SVT (diagnostic + treatment)", "Very short half-life (<10 s). Chest tightness/bronchospasm. Contraindicated in asthma → use verapamil"],
  ].forEach((row, i) => tableRow(s, row, LX, 5.92 + i * 0.235, i));

  s.addText("⚠ Doses are for average adults with normal renal/hepatic function. Always adjust for patient factors.", {
    x: 0.15, y: 7.3, w: 13, h: 0.18, fontSize: 6.5, fontFace: "Calibri", color: C.redLt, italic: true
  });
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 4 - RESPIRATORY + NEUROLOGY DRUGS
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 7.5, fill: { color: C.offWhite }, line: { color: C.offWhite, width: 0 } });
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 0.5, fill: { color: C.green }, line: { color: C.green, width: 0 } });
  s.addText("RESPIRATORY + NEUROLOGY DRUGS", { x: 0.2, y: 0, w: 10, h: 0.5, fontSize: 15, fontFace: "Calibri", color: C.white, bold: true, valign: "middle" });
  s.addText("Slide 4 of 6", { x: 10.3, y: 0, w: 2.8, h: 0.5, fontSize: 9, fontFace: "Calibri", color: "A3CFAA", align: "right", valign: "middle" });

  const LX = 0.15;
  const cols = ["Drug", "Standard Dose", "Route/Freq", "Indication", "Key Notes"];

  // RESPIRATORY
  sectionLabel(s, "BRONCHODILATORS — RESPIRATORY", LX, 0.56, 8.55, C.green);
  tableHeader(s, LX, 0.82, cols);
  [
    ["Salbutamol (SABA)", "100–200 mcg (2–4 puffs) PRN. Neb: 2.5–5 mg", "Inhaler/Neb", "Asthma/COPD relief, acute asthma", "⚠ Tachycardia, hypokalaemia (high doses/nebs). Continuous neb in severe asthma"],
    ["Ipratropium (SAMA)", "Neb: 250–500 mcg QDS. MDI: 20–40 mcg TDS–QDS", "Inhaler/Neb", "COPD, acute asthma adjunct", "Additive effect with salbutamol. Caution in glaucoma/urinary retention"],
    ["Salmeterol (LABA)", "50 mcg BD (in ICS/LABA combo)", "Inhaler BD", "Asthma step 3+ (with ICS), COPD maintenance", "⚠ Never use without ICS in asthma. Vilanterol, formoterol similar"],
    ["Tiotropium (LAMA)", "18 mcg OD (Handihaler) or 2.5 mcg (Respimat)", "Inhaler OD", "COPD maintenance (first-line)", "Reduces exacerbations. Dry mouth, urinary retention"],
    ["Beclometasone (ICS)", "100–400 mcg BD (low–high dose ranges vary by device)", "Inhaler BD", "Asthma step 2+ maintenance", "Rinse mouth after use (prevent oral candidiasis)"],
    ["Prednisolone", "30–50 mg OD x 5 days (acute); chronic varies", "PO OD", "Acute asthma, AECOPD, allergic reactions, IBD, RA, vasculitis", "Monitor glucose/BP. Adrenal suppression >3 weeks. Bone protection if long-term"],
    ["Magnesium Sulphate", "2 g in 100 mL 0.9% NaCl over 20 min IV (single dose)", "IV", "Severe/life-threatening acute asthma (refractory to nebulisers)", "Bronchodilator + anti-inflammatory. Monitor BP during infusion"],
    ["Montelukast (LTRA)", "10 mg OD", "PO nocte", "Asthma step 3 add-on, allergic rhinitis", "⚠ Neuropsychiatric SE reported (anxiety, suicidal ideation) – counsel patient"],
  ].forEach((row, i) => tableRow(s, row, LX, 1.06 + i * 0.235, i));

  // NEUROLOGY
  sectionLabel(s, "NEUROLOGY — SEIZURES / HEADACHE / STROKE", LX, 3.02, 8.55, C.purple);
  tableHeader(s, LX, 3.28, cols);
  [
    ["Lorazepam", "4 mg IV/IM or buccal (max 2 doses)", "IV/IM/buccal", "Status epilepticus (1st line)", "Give slowly IV. Respiratory depression risk. Have resuscitation ready"],
    ["Midazolam", "10 mg buccal/IM (IM in community, buccal in hospital)", "Buccal/IM", "SE 1st line (if no IV access)", "Buccal preferred in paediatrics/community"],
    ["Levetiracetam", "60 mg/kg IV over 15 min (max 4.5 g) for SE. Maintenance: 500–1500 mg BD", "IV/PO BD", "SE 2nd line, focal epilepsy, generalised epilepsy", "Few drug interactions. Mood/behavioural SE. Safe in renal (dose adj required)"],
    ["Sodium Valproate", "SE: 40 mg/kg IV over 15 min. Oral: 500–2000 mg/day in divided doses", "IV/PO BD–TDS", "Generalised epilepsy, JME, SE (2nd line)", "⚠ Major teratogen – AVOID in women of childbearing potential (VALPROATE PREGNANCY PREVENTION PROGRAMME)"],
    ["Lamotrigine", "Start 25 mg OD x2 wks, titrate slowly to 100–200 mg BD", "PO BD", "Focal epilepsy, Generalised, bipolar disorder", "⚠ Slow titration mandatory (Stevens-Johnson syndrome risk if escalated quickly)"],
    ["Carbamazepine", "100–200 mg BD titrated to 400–1200 mg/day", "PO BD", "Focal epilepsy, trigeminal neuralgia", "⚠ Induces CYP450. Aplastic anaemia (rare). Hyponatraemia. Many interactions"],
    ["Sumatriptan", "50–100 mg PO or 6 mg SC or 10–20 mg nasal", "PO/SC/nasal", "Acute migraine, acute cluster headache (SC)", "Do NOT use within 24h of ergotamine. SC fastest onset for cluster"],
    ["Alteplase (tPA)", "0.9 mg/kg IV (max 90 mg); 10% as bolus, rest over 60 min", "IV infusion", "Ischaemic stroke <4.5h from onset", "⚠ Strict BP control (<185/110 before). Multiple contraindications. Risk of haemorrhagic transformation"],
  ].forEach((row, i) => tableRow(s, row, LX, 3.52 + i * 0.235, i));

  s.addText("⚠ Doses are for average adults with normal renal/hepatic function. Always adjust for patient factors.", {
    x: 0.15, y: 7.3, w: 13, h: 0.18, fontSize: 6.5, fontFace: "Calibri", color: C.redLt, italic: true
  });
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 5 - ENDOCRINE + GI DRUGS
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 7.5, fill: { color: C.offWhite }, line: { color: C.offWhite, width: 0 } });
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 0.5, fill: { color: C.amber }, line: { color: C.amber, width: 0 } });
  s.addText("ENDOCRINE + GASTROINTESTINAL DRUGS", { x: 0.2, y: 0, w: 10, h: 0.5, fontSize: 15, fontFace: "Calibri", color: C.white, bold: true, valign: "middle" });
  s.addText("Slide 5 of 6", { x: 10.3, y: 0, w: 2.8, h: 0.5, fontSize: 9, fontFace: "Calibri", color: "F5DFA0", align: "right", valign: "middle" });

  const LX = 0.15;
  const cols = ["Drug", "Standard Dose", "Route/Freq", "Indication", "Key Notes"];

  sectionLabel(s, "DIABETES DRUGS", LX, 0.56, 8.55, C.amber);
  tableHeader(s, LX, 0.82, cols);
  [
    ["Metformin", "500 mg OD–BD initially; titrate to 1000 mg BD (max 3g/day)", "PO OD–BD with food", "T2DM first-line (if eGFR ≥30)", "⚠ Hold if eGFR <30, contrast, surgery, illness (sick-day rules). GI SE – take with food. B12 deficiency long-term"],
    ["Empagliflozin (SGLT2i)", "10–25 mg OD", "PO OD (morning)", "T2DM + CVD/HF/CKD, HFrEF (even without DM), HFpEF", "⚠ Hold during illness/surgery (DKA risk). Genital infections. NOT for eGFR <20 for glucose lowering"],
    ["Dapagliflozin (SGLT2i)", "10 mg OD", "PO OD", "T2DM, HFrEF, HFpEF, CKD protection", "Same class as empagliflozin. Euglycaemic DKA risk"],
    ["Semaglutide (GLP-1 RA)", "PO: 3–14 mg OD. SC: 0.25–1 mg weekly (Ozempic). 2.4 mg weekly (Wegovy – obesity)", "PO OD or SC weekly", "T2DM + obesity/CVD, obesity treatment", "GI SE (nausea, vomiting) – start low. Pancreatitis risk. Weight loss benefit"],
    ["Liraglutide (GLP-1 RA)", "0.6 mg SC OD x1 wk → 1.2 mg → 1.8 mg OD", "SC OD", "T2DM + CVD risk, obesity (3 mg Saxenda)", "LEADER trial: reduced CV events. Pancreatitis, gallstones"],
    ["Sitagliptin (DPP-4i)", "100 mg OD (50 mg if eGFR 30–50; 25 mg if eGFR <30)", "PO OD", "T2DM add-on (weight neutral)", "Well tolerated. Nasopharyngitis, URTI. No hypoglycaemia risk alone"],
    ["Gliclazide (SU)", "40–320 mg OD–BD (MR: 30–120 mg OD)", "PO OD–BD", "T2DM (when other agents not suitable)", "⚠ Hypoglycaemia risk. Weight gain. Safer SU than glibenclamide in elderly"],
    ["Insulin Glargine/Detemir", "0.1–0.2 units/kg/day SC initially; titrate to FBG", "SC OD (nocte)", "T1DM basal, T2DM add-on", "Flat peakless profile. Titrate by 2 units every 3 days to FBG target 4–7 mmol/L"],
    ["Insulin Aspart/Lispro", "4–10 units SC with meals (titrate to post-prandial BG)", "SC with meals", "T1DM bolus, T2DM mealtime", "Inject immediately before or with meal. May give after eating in uncertain intake"],
  ].forEach((row, i) => tableRow(s, row, LX, 1.06 + i * 0.235, i));

  sectionLabel(s, "THYROID DRUGS", LX, 3.21, 8.55, "7B4F00");
  tableHeader(s, LX, 3.47, cols);
  [
    ["Levothyroxine (T4)", "Start 25–50 mcg OD (1.6 mcg/kg ideal), titrate to TSH", "PO OD (empty stomach)", "Hypothyroidism", "Start low in elderly/IHD (25 mcg). Check TSH every 6–8 wk until stable, then 6–12 monthly"],
    ["Carbimazole", "20–40 mg OD initially; maintenance 5–15 mg OD", "PO OD", "Hyperthyroidism (Graves', toxic nodule)", "⚠ Agranulocytosis (sore throat = STOP + urgent FBC). LFTs. First-trimester: use PTU"],
    ["Propylthiouracil (PTU)", "200–400 mg/day in divided doses initially", "PO BD–TDS", "Hyperthyroidism (1st trimester pregnancy, thyroid storm)", "⚠ Hepatotoxicity (monitor LFTs). Agranulocytosis risk. Block-replace regimen in thyroid storm"],
  ].forEach((row, i) => tableRow(s, row, LX, 3.71 + i * 0.235, i));

  sectionLabel(s, "GI DRUGS — PPI, ANTIEMETICS, LAXATIVES", LX, 4.41, 8.55, C.green);
  tableHeader(s, LX, 4.67, cols);
  [
    ["Omeprazole (PPI)", "20–40 mg OD. IV: 80 mg bolus + 8 mg/h (UGIB)", "PO OD (before food) / IV", "GORD, PUD, H. pylori eradication, UGIB, aspirin/NSAID gastroprotection", "⚠ Avoid long-term without indication (C. diff risk, hypomagnesaemia, B12 deficiency)"],
    ["Metoclopramide", "10 mg TDS (max 5 days)", "PO/IV/IM TDS", "Nausea/vomiting, gastroparesis, migraine adjunct", "⚠ Extrapyramidal SE (dystonia esp. young females). Max 5 days. Avoid in Parkinson's"],
    ["Ondansetron", "4–8 mg TDS", "PO/IV/IM TDS", "Chemotherapy-induced N&V, post-op N&V, hospital N&V", "⚠ QT prolongation (check ECG + K+). Constipation. 5-HT3 antagonist"],
    ["Cyclizine", "50 mg TDS", "PO/IV/IM TDS", "N&V (including vestibular, post-op, opioid-induced)", "Sedating. Anticholinergic SE. Safe in pregnancy"],
    ["Lactulose", "15–30 mL BD (titrate)", "PO BD", "Constipation, hepatic encephalopathy (lactulose 3–4 soft stools/day)", "May take 48h to work. Flatulence. High dose in HE to trap NH3"],
    ["Senna", "7.5–15 mg OD–BD", "PO nocte", "Constipation (stimulant laxative)", "Works overnight. Avoid in bowel obstruction"],
  ].forEach((row, i) => tableRow(s, row, LX, 4.91 + i * 0.235, i));

  s.addText("⚠ Doses are for average adults with normal renal/hepatic function. Always adjust for patient factors.", {
    x: 0.15, y: 7.3, w: 13, h: 0.18, fontSize: 6.5, fontFace: "Calibri", color: C.redLt, italic: true
  });
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 6 - ANTIBIOTICS + EMERGENCY DRUGS
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 7.5, fill: { color: C.offWhite }, line: { color: C.offWhite, width: 0 } });
  s.addShape(pres.ShapeType.rect, { x: 0, y: 0, w: 13.3, h: 0.5, fill: { color: C.red }, line: { color: C.red, width: 0 } });
  s.addText("ANTIBIOTICS + EMERGENCY / RESUSCITATION DRUGS", { x: 0.2, y: 0, w: 10, h: 0.5, fontSize: 14, fontFace: "Calibri", color: C.white, bold: true, valign: "middle" });
  s.addText("Slide 6 of 6", { x: 10.3, y: 0, w: 2.8, h: 0.5, fontSize: 9, fontFace: "Calibri", color: "F5B8B8", align: "right", valign: "middle" });

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  const cols = ["Drug", "Standard Dose", "Route/Freq", "Indication", "Key Notes"];

  sectionLabel(s, "COMMON ANTIBIOTICS", LX, 0.56, 8.55, C.red);
  tableHeader(s, LX, 0.82, cols);
  [
    ["Amoxicillin", "500 mg TDS. High dose: 1 g TDS. IV: 1 g TDS", "PO/IV TDS", "CAP (mild), UTI, otitis media, sinusitis, strep throat", "Penicillin. Check allergy. Rash if given in EBV (glandular fever)"],
    ["Co-amoxiclav (Augmentin)", "625 mg TDS PO or 1.2 g TDS IV", "PO/IV TDS", "CAP (moderate-severe), UTI, abdominal infections, cellulitis", "Cholestatic hepatitis risk (with/after use). Broad spectrum penicillin + BLI"],
    ["Piperacillin-Tazobactam (Tazocin)", "4.5 g IV every 6–8h (q6h for severe sepsis)", "IV q6–8h", "HAP, severe sepsis, intra-abdominal, Pseudomonas cover", "Broad spectrum. Add vancomycin/teicoplanin for MRSA cover"],
    ["Clarithromycin", "250–500 mg BD PO or IV", "PO/IV BD", "Atypical pneumonia (Mycoplasma, Legionella), CAP (add-on), H. pylori, skin infections (penicillin allergy)", "⚠ QT prolongation. CYP3A4 inhibitor (many interactions – statins, warfarin). GI SE"],
    ["Doxycycline", "100–200 mg OD (loading 200 mg)", "PO OD", "CAP (mild, PCN allergy), Chlamydia, LRTI, Lyme disease, malaria prophylaxis", "Take upright with water (oesophageal ulceration). Photosensitivity. Avoid in pregnancy/children <8y"],
    ["Trimethoprim", "200 mg BD x 7 days", "PO BD", "Uncomplicated lower UTI", "Folate antagonist – caution in pregnancy. Check local resistance patterns"],
    ["Nitrofurantoin", "50 mg QDS x 5–7 days (or 100 mg MR BD)", "PO QDS/BD", "Lower UTI (not upper – does not achieve therapeutic renal tissue levels)", "⚠ Avoid if eGFR <30 (ineffective + toxic). Pulmonary SE with long-term use"],
    ["Ceftriaxone", "1–2 g IV OD (2 g for meningitis/serious infections)", "IV OD", "Meningitis (with amoxicillin for Listeria cover), severe CAP, spontaneous bacterial peritonitis, gonorrhoea", "3rd gen cephalosporin. Biliary sludge with prolonged use. Avoid in hyperbilirubinaemia (neonates)"],
    ["Metronidazole", "400 mg TDS PO or 500 mg TDS IV", "PO/IV TDS", "Anaerobic infections, C. diff (oral, 2nd line), intra-abdominal, pelvic, dental infections", "⚠ Disulfiram reaction with alcohol. Peripheral neuropathy (prolonged use). Metallic taste"],
    ["Vancomycin", "15–20 mg/kg IV BD (AUC-guided dosing preferred)", "IV BD (infuse over ≥60 min)", "MRSA, C. diff (oral PO only for colitis), line infections, endocarditis (staph)", "⚠ Nephrotoxic + ototoxic. Red man syndrome if rapid infusion. Therapeutic drug monitoring required"],
  ].forEach((row, i) => tableRow(s, row, LX, 1.06 + i * 0.235, i));

  sectionLabel(s, "EMERGENCY / RESUSCITATION DRUGS", LX, 3.46, 8.55, "8B0000");
  tableHeader(s, LX, 3.72, cols);
  [
    ["Adrenaline (Epinephrine)", "Cardiac arrest: 1 mg IV every 3–5 min. Anaphylaxis: 0.5 mg (500 mcg) IM (thigh)", "IV / IM", "Cardiac arrest (PEA/asystole/VF), anaphylaxis, severe asthma", "IM adrenaline for anaphylaxis: use anterolateral thigh. Auto-injector: 0.3–0.5 mg. IV for cardiac arrest only"],
    ["Atropine", "0.5–1 mg IV (repeat to max 3 mg). Bradycardia: 0.6–1.2 mg", "IV", "Symptomatic bradycardia, organophosphate poisoning, pre-op antisialagogue", "Cholinergic blockade. Tachycardia, dry mouth, urinary retention, blurred vision"],
    ["GTN (Glyceryl trinitrate)", "0.4 mg sublingual spray PRN. IV: 1–10 mg/h infusion", "SL / IV infusion", "Acute angina, ACS pain relief, acute hypertensive emergency, pulmonary oedema", "⚠ Hypotension – have patient sitting/lying. Do NOT use if systolic BP <90 or if PDE5 inhibitor taken in 24–48h"],
    ["Naloxone", "0.4–2 mg IV/IM/SC; repeat every 2–3 min until respiratory rate improves (max 10 mg)", "IV/IM/SC", "Opioid overdose (respiratory depression)", "Short half-life (<45 min) – may need repeated doses or infusion (opioid lasts longer). Precipitates withdrawal"],
    ["Flumazenil", "200 mcg IV over 15 sec; repeat 100 mcg every 60 sec to max 1 mg", "IV", "Benzodiazepine overdose reversal", "⚠ Short half-life – re-sedation likely. Can precipitate seizures in BZD-dependent patients. NOT routine in OD"],
    ["Hydrocortisone", "100–200 mg IV QDS (acute adrenal crisis). 100 mg IV pre-op (at-risk patients)", "IV QDS", "Addisonian crisis, severe asthma, anaphylaxis (2nd line), hypercalcaemia (lymphoma)", "Give with saline in Addisonian crisis. Switch to oral once stable"],
    ["Dextrose (Glucose)", "50 mL of 50% glucose IV (or 150 mL of 20% glucose)", "IV bolus", "Severe hypoglycaemia (unconscious patient)", "Flush cannula well after 50% glucose (irritant). Repeat BG in 15 min. Follow with snack once conscious"],
    ["Glucagon", "1 mg IM/SC/IV", "IM/SC", "Severe hypoglycaemia (no IV access), beta-blocker overdose", "Effects take 10–15 min. N&V common. Give carbohydrate once conscious. Limited glycogen stores in fasting/alcohol"],
  ].forEach((row, i) => tableRow(s, row, LX, 3.96 + i * 0.235, i));

  s.addText("⚠ Doses are for average adults with normal renal/hepatic function. Always adjust for patient factors.", {
    x: 0.15, y: 7.3, w: 13, h: 0.18, fontSize: 6.5, fontFace: "Calibri", color: C.redLt, italic: true
  });
}

// ──────────────────────────────────────────────────────────────────────────────
pres.writeFile({ fileName: "/home/daytona/workspace/drug-cheatsheet/GenMed_Drug_Doses_CheatSheet.pptx" })
  .then(() => console.log("DONE: GenMed_Drug_Doses_CheatSheet.pptx created"))
  .catch(e => { console.error("ERROR:", e); process.exit(1); });

const pptxgen = require("pptxgenjs");

const pres = new pptxgen();
pres.layout = "LAYOUT_WIDE"; // 13.3" x 7.5"
pres.title = "Drug Interactions Quick Reference";

// ─── COLOUR PALETTE ───────────────────────────────────────────────────────────
const C = {
  // Severity colours
  contraindicated: "8B0000",  // deep red
  ciLight:         "FDECEA",
  serious:         "C0392B",  // red
  serLight:        "FDECEA",
  major:           "D35400",  // dark orange
  majLight:        "FEF0E6",
  moderate:        "B7770D",  // amber
  modLight:        "FEF9E7",
  monitor:         "1A6B3C",  // green
  monLight:        "EAF6EE",
  // UI
  navy:    "0D1B2A",
  teal:    "1B5E8C",
  slate:   "374151",
  slateL:  "6B7280",
  offWhite:"F4F6F9",
  white:   "FFFFFF",
  rowAlt:  "F0F4FA",
  hdrBg:   "1B3A5C",
  hdrText: "FFFFFF",
  subHdr:  "2563EB",
};

// Severity config
const SEV = {
  X: { label: "CONTRAINDICATED", bg: "8B0000",  light: "FDECEA", text: "FFFFFF" },
  S: { label: "SERIOUS",         bg: "C0392B",  light: "FDECEA", text: "FFFFFF" },
  M: { label: "MAJOR",           bg: "D35400",  light: "FEF0E6", text: "FFFFFF" },
  W: { label: "MODERATE",        bg: "B7770D",  light: "FEF9E7", text: "FFFFFF" },
  O: { label: "MONITOR",         bg: "1A6B3C",  light: "EAF6EE", text: "FFFFFF" },
};

// ─── HELPERS ──────────────────────────────────────────────────────────────────
function bg(slide, x, y, w, h, color, rounded = false) {
  slide.addShape(rounded ? pres.ShapeType.roundRect : pres.ShapeType.rect, {
    x, y, w, h,
    fill: { color },
    line: { color, width: 0 },
    ...(rounded ? { rectRadius: 0.05 } : {}),
  });
}

function txt(slide, text, x, y, w, h, opts = {}) {
  const { color = C.slate, sz = 7.5, bold = false, italic = false, align = "left", valign = "middle", margin = 3, wrap = true } = opts;
  slide.addText(text, { x, y, w, h, fontSize: sz, fontFace: "Calibri", color, bold, italic, align, valign, margin, wrap });
}

function titleBar(slide, title, sub, color) {
  bg(slide, 0, 0, 13.3, 0.52, color);
  txt(slide, title, 0.18, 0, 9.5, 0.52, { color: C.white, sz: 15, bold: true, valign: "middle" });
  txt(slide, sub, 9.8, 0, 3.3, 0.52, { color: "C5D8F0", sz: 9, align: "right", valign: "middle" });
}

function severityBadge(slide, sev, x, y) {
  const cfg = SEV[sev];
  bg(slide, x, y + 0.01, 1.05, 0.2, cfg.bg, true);
  txt(slide, cfg.label, x, y + 0.01, 1.05, 0.2, { color: cfg.text, sz: 5.8, bold: true, align: "center", margin: 1 });
}

// Column layout: Drug A | Drug B | Severity badge | Mechanism | Effect | Management
// Widths:         1.5      1.4       1.1              2.3          2.3       2.45   = 11.05 + 0.15 margins = ~13.2"
const SX = 0.12; // start x
const CW = [1.5, 1.4, 1.1, 2.35, 2.35, 2.45];

function cx(col) {
  let x = SX;
  for (let i = 0; i < col; i++) x += CW[i];
  return x;
}

const HDR_COLS = ["Drug A", "Drug B", "Severity", "Mechanism", "Clinical Effect", "Management"];

function tableHeader(slide, y) {
  HDR_COLS.forEach((label, i) => {
    bg(slide, cx(i), y, CW[i], 0.22, C.hdrBg);
    txt(slide, label, cx(i), y, CW[i], 0.22, { color: C.hdrText, sz: 7.2, bold: true, align: "center", margin: 1 });
  });
}

function interactionRow(slide, data, y, rowIdx) {
  // data = [drugA, drugB, severity, mechanism, effect, management]
  const [drugA, drugB, sev, mech, effect, mgmt] = data;
  const rowBg = rowIdx % 2 === 0 ? C.white : C.rowAlt;
  const cfg = SEV[sev];
  const RH = 0.25;

  // Background
  CW.forEach((w, i) => {
    const cellBg = i === 2 ? cfg.light : rowBg;
    bg(slide, cx(i), y, w, RH, cellBg);
    // border line
    slide.addShape(pres.ShapeType.line, { x: cx(i), y: y + RH, w: w, h: 0, line: { color: "D1D5DB", width: 0.5 } });
  });

  // Drug A
  txt(slide, drugA, cx(0), y, CW[0], RH, { sz: 7.8, bold: true, color: C.navy, margin: 3 });
  // Drug B
  txt(slide, drugB, cx(1), y, CW[1], RH, { sz: 7.8, bold: true, color: C.teal, margin: 3 });
  // Severity badge
  severityBadge(slide, sev, cx(2) + 0.03, y + 0.025);
  // Mechanism
  txt(slide, mech, cx(3), y, CW[3], RH, { sz: 7, italic: true, color: C.slateL, margin: 3 });
  // Effect
  txt(slide, effect, cx(4), y, CW[4], RH, { sz: 7.3, color: C.slate, margin: 3 });
  // Management
  txt(slide, mgmt, cx(5), y, CW[5], RH, { sz: 7.3, bold: false, color: "1A3A1A", margin: 3 });
}

function sectionDivider(slide, label, y, color) {
  bg(slide, SX, y, 13.06, 0.21, color);
  txt(slide, label, SX + 0.1, y, 12.8, 0.21, { color: C.white, sz: 8, bold: true, valign: "middle", charSpacing: 1 });
}

function footer(slide) {
  txt(slide, "For educational use only. Severity ratings based on pharmacological principles and clinical guidelines. Always verify with current BNF/local formulary.", 0.12, 7.33, 13, 0.16, { sz: 6.2, italic: true, color: C.slateL });
}

function legendBar(slide, y) {
  const items = [
    ["X", "CONTRAINDICATED"],
    ["S", "SERIOUS"],
    ["M", "MAJOR"],
    ["W", "MODERATE"],
    ["O", "MONITOR"],
  ];
  txt(slide, "SEVERITY KEY:", 0.12, y, 1.2, 0.22, { sz: 7, bold: true, color: C.slate });
  items.forEach(([key, label], i) => {
    const cfg = SEV[key];
    const x = 1.3 + i * 2.35;
    bg(slide, x, y + 0.02, 1.1, 0.19, cfg.bg, true);
    txt(slide, cfg.label, x, y + 0.02, 1.1, 0.19, { color: cfg.text, sz: 6.5, bold: true, align: "center", margin: 1 });
  });
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 1 — COVER
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  bg(s, 0, 0, 13.3, 7.5, C.navy);
  bg(s, 0, 0, 13.3, 0.07, "2563EB");
  bg(s, 0, 7.43, 13.3, 0.07, "2563EB");

  // Decorative diagonal accent band
  s.addShape(pres.ShapeType.rect, { x: 8.8, y: 0, w: 4.5, h: 7.5, fill: { color: "0F2744" }, line: { color: "0F2744", width: 0 } });

  txt(s, "DRUG INTERACTIONS", 0.8, 1.3, 8, 1.0, { color: "60A5FA", sz: 38, bold: true, align: "left" });
  txt(s, "Quick Reference", 0.8, 2.28, 8, 0.75, { color: C.white, sz: 44, bold: true, align: "left" });
  txt(s, "FOR CLINICAL MEDICAL STUDENTS", 0.8, 3.1, 8, 0.4, { color: "93C5FD", sz: 13, bold: true, align: "left", charSpacing: 3 });

  // Severity legend on cover
  const sevItems = [
    ["CONTRAINDICATED", "8B0000"],
    ["SERIOUS",         "C0392B"],
    ["MAJOR",           "D35400"],
    ["MODERATE",        "B7770D"],
    ["MONITOR",         "1A6B3C"],
  ];
  txt(s, "SEVERITY SCALE", 0.8, 3.8, 8, 0.28, { color: "93C5FD", sz: 9, bold: true, charSpacing: 2 });
  sevItems.forEach(([label, color], i) => {
    bg(s, 0.8 + i * 1.5, 4.08, 1.38, 0.28, color, true);
    txt(s, label, 0.8 + i * 1.5, 4.08, 1.38, 0.28, { color: C.white, sz: 6.5, bold: true, align: "center", margin: 1 });
  });

  // Slide list
  const slides = [
    ["2", "CYP450 Drug Interactions",           "2563EB"],
    ["3", "Cardiovascular Drug Interactions",   "1A5276"],
    ["4", "Antibiotics + Drug Interactions",    "145A32"],
    ["5", "CNS + Psychiatric Drug Interactions","4A235B"],
    ["6", "Endocrine + Renal Interactions",     "6E2F0A"],
    ["7", "High-Risk Pairs at a Glance",        "78281F"],
  ];
  slides.forEach(([num, label, color], i) => {
    const x = 9.1;
    const y = 0.9 + i * 0.88;
    bg(s, x, y, 3.9, 0.68, color, true);
    txt(s, num, x + 0.08, y, 0.4, 0.68, { color: "93C5FD", sz: 18, bold: true, align: "center" });
    txt(s, label, x + 0.52, y, 3.25, 0.68, { color: C.white, sz: 9, bold: false, valign: "middle", wrap: true });
  });

  txt(s, "For educational use only. Always verify with current BNF / local formulary.", 0.8, 6.8, 12, 0.4, { color: "4B5563", italic: true, sz: 8 });
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 2 — CYP450 INTERACTIONS (Statins, Macrolides, Azoles, Warfarin)
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  bg(s, 0, 0, 13.3, 7.5, C.offWhite);
  titleBar(s, "CYP450-MEDIATED DRUG INTERACTIONS", "Slide 2 of 7", "1A3A5C");
  legendBar(s, 0.56);

  sectionDivider(s, "STATINS — CYP3A4 Inhibitors increase statin levels → Myopathy / Rhabdomyolysis risk", 0.82, "8B3A00");
  tableHeader(s, 1.03);
  [
    ["Simvastatin / Lovastatin", "Clarithromycin / Erythromycin (Macrolides)", "X", "Macrolides inhibit CYP3A4 → simvastatin/lovastatin AUC ↑ 5–12×", "Severe myopathy, rhabdomyolysis, AKI (myoglobinuria)", "CONTRAINDICATED. Use azithromycin (does not inhibit CYP3A4) or switch to pravastatin/rosuvastatin (not CYP3A4)"],
    ["Simvastatin / Lovastatin", "Fluconazole / Itraconazole / Ketoconazole (Azoles)", "X", "Azole antifungals = potent CYP3A4 inhibitors; statin levels increase 10-20×", "Rhabdomyolysis, acute renal failure", "CONTRAINDICATED. Use fluconazole if needed → switch to pravastatin or rosuvastatin"],
    ["Simvastatin / Lovastatin", "Diltiazem / Verapamil (non-DHP CCBs)", "M", "Non-DHP CCBs inhibit CYP3A4 → moderate statin level rise", "Myopathy risk (less severe than macrolides)", "Limit simvastatin ≤10 mg/day with diltiazem or verapamil. Consider atorvastatin as safer alternative"],
    ["Simvastatin / Lovastatin", "Amiodarone", "M", "Amiodarone inhibits CYP3A4 and CYP2C9 → statin AUC ↑", "Myopathy; more pronounced with simvastatin 80 mg", "Limit simvastatin ≤20 mg/day with amiodarone. Atorvastatin/rosuvastatin preferred"],
    ["Atorvastatin", "Clarithromycin / Erythromycin", "S", "CYP3A4 inhibition raises atorvastatin levels (less than simvastatin)", "Myopathy risk (lower than simvastatin)", "Avoid or use lowest dose atorvastatin. Switch to azithromycin or pravastatin/rosuvastatin"],
    ["Any statin", "Gemfibrozil (Fibrate)", "S", "Gemfibrozil inhibits OATP1B1 transporter + glucuronidation → all statins ↑", "Rhabdomyolysis; CETP trial data confirms risk", "Avoid gemfibrozil + statin combination. Use fenofibrate (safer fibrate) if needed"],
    ["Rosuvastatin / Pravastatin", "Cyclosporin", "S", "Cyclosporin inhibits OATP1B1 and MRP2 transporters → statin AUC ↑ 5–7×", "Rhabdomyolysis in transplant patients", "If unavoidable: limit rosuvastatin ≤5 mg/day, pravastatin ≤20 mg/day. Monitor CK"],
  ].forEach((row, i) => interactionRow(s, row, 1.25 + i * 0.25, i));

  sectionDivider(s, "WARFARIN — Multiple CYP450 Interactions (CYP2C9 substrate — narrow therapeutic index)", 3.01, "5B2C6F");
  tableHeader(s, 3.22);
  [
    ["Warfarin", "Fluconazole / Miconazole", "X", "Azoles inhibit CYP2C9 → warfarin (S-enantiomer) metabolism ↓ → INR ↑↑↑", "Major bleeding (GI, intracranial)", "CONTRAINDICATED concurrent use. If azole essential: stop warfarin, bridge with LMWH. Topical miconazole can also interact"],
    ["Warfarin", "Amiodarone", "X", "Amiodarone + active metabolite inhibit CYP2C9 and CYP3A4 (effect persists months after stopping)", "INR doubles within 1–2 weeks; major bleeding", "Reduce warfarin dose by ~30–50% when starting amiodarone. Monitor INR every 3 days until stable. Consider DOAC instead"],
    ["Warfarin", "Clarithromycin / Erythromycin", "S", "CYP3A4 and CYP2C9 inhibition + ↓ gut flora (vitamin K production)", "INR ↑ → bleeding risk", "Monitor INR closely (within 3–5 days of starting). Consider dose reduction. Azithromycin safer"],
    ["Warfarin", "Metronidazole / Ciprofloxacin", "S", "Metronidazole: CYP2C9 inhibition. Ciprofloxacin: unknown mechanism + gut flora ↓", "INR ↑ → bleeding", "Reduce warfarin dose ~25% when prescribing. Check INR at 3–5 days"],
    ["Warfarin", "Rifampicin", "S", "Rifampicin = potent CYP450 inducer → warfarin metabolism ↑↑", "INR ↓ → subtherapeutic anticoagulation → thrombosis", "INR can fall to <1.5 within days. Massive dose increase needed. Consider LMWH/DOAC instead"],
    ["Warfarin", "NSAIDs (Ibuprofen, Naproxen)", "S", "Pharmacodynamic: NSAIDs inhibit platelets + GI mucosal damage; some inhibit CYP2C9", "Bleeding risk ↑↑ (GI haemorrhage especially)", "Avoid NSAIDs in anticoagulated patients. Use paracetamol for analgesia. If unavoidable: add PPI"],
    ["Warfarin", "Phenytoin / Carbamazepine / Phenobarbitone", "M", "Anticonvulsants induce CYP2C9/CYP3A4 → warfarin metabolism ↑", "INR ↓ → subtherapeutic → thrombosis", "Monitor INR frequently when starting/stopping AEDs. May need significantly higher warfarin doses"],
  ].forEach((row, i) => interactionRow(s, row, 3.44 + i * 0.25, i));

  sectionDivider(s, "ORAL CONTRACEPTIVE PILL (OCP) — Enzyme Induction reduces contraceptive efficacy", 5.19, "145A6E");
  tableHeader(s, 5.40);
  [
    ["Combined OCP / Progestogen-only pill", "Rifampicin / Rifabutin", "X", "Rifampicin potently induces CYP3A4 → contraceptive steroid levels ↓↓", "Contraceptive failure → unplanned pregnancy", "OCP unreliable even with added barrier methods during rifampicin. Use LARC (IUD/IUS/DMPA injection). Continue precautions 28 days after stopping rifampicin"],
    ["Combined OCP", "Enzyme-inducing AEDs (phenytoin, carbamazepine, phenobarb, topiramate ≥200 mg)", "S", "CYP3A4 induction ↓ ethinylestradiol and levonorgestrel levels", "Contraceptive failure", "FSRH guidance: avoid OCP or use ≥50 mcg ethinylestradiol (specialist) + barrier. IUD/IUS preferred"],
    ["OCP", "Broad-spectrum antibiotics (amoxicillin, doxycycline)", "O", "Theory: gut flora disruption ↓ enterohepatic recycling of oestrogen — clinical evidence weak/disputed", "Theoretical contraceptive failure risk (small)", "FSRH 2019: no additional contraception needed for non-enzyme-inducing antibiotics. Counsel patients of theoretical risk"],
  ].forEach((row, i) => interactionRow(s, row, 5.62 + i * 0.25, i));

  footer(s);
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 3 — CARDIOVASCULAR INTERACTIONS
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  bg(s, 0, 0, 13.3, 7.5, C.offWhite);
  titleBar(s, "CARDIOVASCULAR DRUG INTERACTIONS", "Slide 3 of 7", "1A3A5C");
  legendBar(s, 0.56);

  sectionDivider(s, "ACE INHIBITORS / ARBs — Hyperkalaemia, Hypotension, Renal Failure", 0.82, "154360");
  tableHeader(s, 1.03);
  [
    ["ACE inhibitor / ARB", "NSAIDs (Ibuprofen, Diclofenac, Naproxen)", "S", "NSAIDs ↓ renal prostaglandins → reduced GFR, ↓ RAS counterregulation; both drugs reduce renal perfusion", "AKI (the 'triple whammy' with diuretics), ↑ K+, ↑ BP (blunted antihypertensive effect)", "Avoid regular NSAIDs in patients on ACEi/ARB, especially the elderly or if on diuretics. Use paracetamol. If essential: monitor U&E/creatinine at 1 week. STOP in acute illness/dehydration"],
    ["ACE inhibitor / ARB", "Potassium-sparing diuretics (Spironolactone, Eplerenone, Amiloride)", "M", "Additive retention of K+ (both drugs reduce aldosterone-driven K+ excretion)", "Hyperkalaemia → cardiac arrhythmias, cardiac arrest", "Combination used intentionally in HFrEF (evidence-based) — requires baseline K+ <5.0 mmol/L and regular monitoring. STOP if K+ >5.5. Avoid in CKD stage 4+"],
    ["ACE inhibitor / ARB", "Trimethoprim / Cotrimoxazole", "M", "Trimethoprim blocks renal K+ secretion (similar to amiloride) → additive hyperkalaemia", "Hyperkalaemia (especially in elderly or CKD)", "Monitor U&E/K+ within 1 week of starting. Reduce dose of trimethoprim if needed. Nitrofurantoin safer alternative for UTI"],
    ["ACE inhibitor", "ARB (Dual RAS Blockade)", "S", "Additive RAAS inhibition → ↓↓ aldosterone, ↑↑ K+, GFR reduction", "Hyperkalaemia, AKI — ONTARGET trial showed harm with dual blockade", "AVOID routine dual ACEi+ARB. Exception: specialist-supervised resistant proteinuric nephropathy. Monitor U&E closely"],
    ["ACE inhibitor / ARB", "Lithium", "M", "ACEi/ARBs ↓ renal lithium excretion via ↓ angiotensin II → GFR effects", "Lithium toxicity (narrow therapeutic index)", "Monitor lithium levels 1 week after starting ACEi/ARB. Dose adjustment likely needed. Symptoms: tremor, confusion, polyuria"],
  ].forEach((row, i) => interactionRow(s, row, 1.25 + i * 0.25, i));

  sectionDivider(s, "BETA-BLOCKERS — Bradycardia, Hypoglycaemia masking, Bronchospasm", 2.52, "1A5276");
  tableHeader(s, 2.73);
  [
    ["Beta-blocker (any)", "Verapamil / Diltiazem (non-DHP CCBs)", "X", "Additive depression of SA and AV node → severe bradycardia, heart block, asystole", "Complete heart block, cardiogenic shock", "CONTRAINDICATED combination (IV verapamil + beta-blocker especially dangerous). Use amlodipine if CCB needed alongside beta-blocker"],
    ["Beta-blocker (any)", "Digoxin", "M", "Additive suppression of AV conduction", "Severe bradycardia, complete heart block", "Use cautiously if combined for AF rate control. Monitor resting HR (target 60–80). ECG monitoring"],
    ["Beta-blocker (any)", "Insulin / Sulfonylurea", "W", "Beta-blockers mask adrenergic hypoglycaemia symptoms (palpitations, tremor) — diaphoresis still present", "Unrecognised hypoglycaemia → prolonged episode", "Counsel diabetic patients. Cardioselective beta-blockers (bisoprolol, atenolol) slightly safer. Use with caution in insulin-dependent DM"],
    ["Beta-blocker (any)", "Adrenaline / Epinephrine", "M", "Non-selective beta-blockers block beta-2 → unopposed alpha → severe hypertension, bradycardia (reflex)", "Hypertensive crisis, bradycardia (especially propranolol)", "Use cardioselective beta-blockers where possible. Anaphylaxis management: give adrenaline IM but may need higher doses + atropine for refractory bradycardia"],
    ["Propranolol / Non-selective BB", "Salbutamol / Salmeterol", "M", "Beta-blocker antagonises beta-2 bronchodilation", "Severe bronchospasm, attenuated bronchodilator response in asthma/COPD", "Avoid non-selective beta-blockers in asthma. Use cardioselective (bisoprolol, atenolol) if beta-blocker essential. Monitor peak flow"],
  ].forEach((row, i) => interactionRow(s, row, 2.95 + i * 0.25, i));

  sectionDivider(s, "DIGOXIN — Narrow Therapeutic Index (target 1.0–2.0 nmol/L)", 4.22, "4A235B");
  tableHeader(s, 4.43);
  [
    ["Digoxin", "Amiodarone", "S", "Amiodarone inhibits P-glycoprotein + CYP2C9/3A4 → digoxin levels ↑↑", "Digoxin toxicity: bradycardia, AV block, nausea, visual changes (yellow-green halos)", "Reduce digoxin dose by 50% when starting amiodarone. Monitor levels and ECG. Titrate to effect"],
    ["Digoxin", "Diltiazem / Verapamil", "S", "Inhibit P-glycoprotein → ↓ renal/biliary digoxin excretion → digoxin ↑ ~70%", "Digoxin toxicity, bradycardia, heart block", "Reduce digoxin dose by 30–50%. Monitor levels. Avoid verapamil + digoxin if possible"],
    ["Digoxin", "Loop / Thiazide diuretics", "M", "Diuretics → hypokalaemia → ↑ digoxin binding to Na+/K+-ATPase → enhanced toxicity", "Arrhythmias and toxicity even at 'normal' digoxin levels", "Monitor K+ (target >4.0 mmol/L in patients on digoxin). Replace K+ aggressively. Monitor ECG"],
    ["Digoxin", "Clarithromycin / Erythromycin", "M", "Macrolides eliminate gut bacteria (Eubacterium lentum) that inactivate digoxin + P-gp inhibition", "Digoxin toxicity (nausea, bradycardia, visual symptoms)", "Monitor digoxin level and ECG within 48–72h of starting macrolide. Use azithromycin if possible"],
    ["Digoxin", "Spironolactone", "W", "Spironolactone interferes with some digoxin assay methods (falsely elevated levels)", "Potential over-treatment based on falsely elevated digoxin assay", "Be aware of assay interference. Use clinical symptoms + ECG to guide dosing alongside levels"],
  ].forEach((row, i) => interactionRow(s, row, 4.65 + i * 0.25, i));

  sectionDivider(s, "QT-PROLONGING DRUGS — Additive risk of Torsades de Pointes (TdP)", 5.91, "78281F");
  tableHeader(s, 6.12);
  [
    ["Amiodarone", "Any QT-prolonging drug (ondansetron, clarithromycin, haloperidol, fluconazole, citalopram, methadone)", "X", "Additive QT prolongation → triggered arrhythmia mechanism (early afterdepolarisations)", "Torsades de Pointes → VF → sudden cardiac death", "Check CredibleMeds/AzCERT database for all QT-risk drugs. Avoid combinations. Monitor ECG + electrolytes (K+, Mg2+). Correct electrolytes before starting QT drugs"],
    ["Sotalol", "Clarithromycin / Azithromycin / Ciprofloxacin", "S", "Class III anti-arrhythmic with inherent QT prolongation + antibiotic-mediated QT prolongation", "TdP, VF", "Avoid. If antibiotic needed: choose agent with lowest QT risk (e.g., amoxicillin). ECG mandatory if combination unavoidable"],
    ["Methadone", "Fluconazole + SSRIs/TCAs", "S", "Multiple mechanisms: CYP3A4 inhibition ↑ methadone + additive QT", "TdP (methadone has high intrinsic QT risk)", "Baseline ECG before starting methadone. Avoid QT-prolonging drugs. ECG if QTc >450 ms (men) or >470 ms (women)"],
  ].forEach((row, i) => interactionRow(s, row, 6.34 + i * 0.25, i));

  footer(s);
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 4 — ANTIBIOTICS + DRUG INTERACTIONS
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  bg(s, 0, 0, 13.3, 7.5, C.offWhite);
  titleBar(s, "ANTIBIOTICS — DRUG INTERACTIONS", "Slide 4 of 7", "145A32");
  legendBar(s, 0.56);

  sectionDivider(s, "MACROLIDES (Clarithromycin / Erythromycin) — Potent CYP3A4 Inhibitors", 0.82, "145A32");
  tableHeader(s, 1.03);
  [
    ["Clarithromycin / Erythromycin", "Simvastatin / Lovastatin", "X", "CYP3A4 inhibition → statin AUC ↑ 5–12×", "Rhabdomyolysis, AKI", "CONTRAINDICATED. Use azithromycin or switch to pravastatin/rosuvastatin. See slide 2"],
    ["Clarithromycin / Erythromycin", "Warfarin", "S", "CYP2C9 + CYP3A4 inhibition; gut flora ↓ vitamin K production", "INR ↑↑ → major bleeding", "Monitor INR within 3–5 days. Anticipate dose reduction ~20–30%"],
    ["Clarithromycin / Erythromycin", "Colchicine", "X", "CYP3A4 inhibition + P-gp inhibition → colchicine AUC ↑ 3×", "Colchicine toxicity: diarrhoea, myopathy, multi-organ failure, death", "CONTRAINDICATED (especially in renal impairment). Use azithromycin. If unavoidable: max colchicine 0.5 mg total dose"],
    ["Clarithromycin / Erythromycin", "Carbamazepine", "S", "CYP3A4 inhibition → carbamazepine level ↑↑", "Carbamazepine toxicity: diplopia, ataxia, drowsiness, seizures", "Monitor carbamazepine levels. Use azithromycin or doxycycline. Anticipate 50% level rise"],
    ["Clarithromycin", "Digoxin", "M", "P-gp inhibition + gut bacteria elimination → digoxin ↑", "Digoxin toxicity (nausea, bradycardia, vision)", "See digoxin section. Use azithromycin if possible. Monitor digoxin level"],
    ["Clarithromycin / Erythromycin", "QT-prolonging drugs (antipsychotics, methadone, sotalol)", "S", "Additive QT prolongation (macrolides themselves prolong QTc)", "Torsades de Pointes → VF", "Check QTc before prescribing. Avoid combination. Azithromycin also has QT risk (less CYP interaction but QT-prolonging)"],
  ].forEach((row, i) => interactionRow(s, row, 1.25 + i * 0.25, i));

  sectionDivider(s, "FLUOROQUINOLONES (Ciprofloxacin / Levofloxacin) — QT Risk + Metal chelation + CYP1A2", 2.77, "1A5276");
  tableHeader(s, 2.98);
  [
    ["Ciprofloxacin / Levofloxacin", "QT-prolonging drugs (amiodarone, haloperidol, ondansetron)", "S", "Fluoroquinolones prolong QTc independently; additive with other QT drugs", "TdP, VF", "ECG before prescribing. Avoid combining. Levofloxacin has higher QT risk than ciprofloxacin"],
    ["Ciprofloxacin", "Theophylline / Aminophylline", "M", "Ciprofloxacin inhibits CYP1A2 → theophylline AUC ↑ 50–100%", "Theophylline toxicity: tachycardia, seizures, nausea", "Reduce theophylline dose by 30–50% or avoid. Monitor theophylline levels. Use amoxicillin if possible"],
    ["Ciprofloxacin", "Warfarin", "S", "CYP1A2 inhibition → minor effect + mechanism unclear; clinically significant", "INR ↑ → bleeding", "Monitor INR within 3–5 days. Consider trimethoprim or amoxicillin as safer alternatives"],
    ["Ciprofloxacin / Any fluoroquinolone", "Oral iron / Antacids / Calcium supplements", "W", "Metal cations chelate fluoroquinolone in gut → ↓ absorption by up to 75%", "Antibiotic treatment failure", "Take fluoroquinolone 2 hours before or 4 hours after iron/antacids/calcium supplements"],
    ["Ciprofloxacin", "NSAIDs", "W", "Fluoroquinolones lower seizure threshold; NSAIDs inhibit GABA-A → additive CNS excitability", "Seizures (especially in elderly or with pre-existing seizure risk)", "Use paracetamol for analgesia where possible. Caution in epilepsy"],
  ].forEach((row, i) => interactionRow(s, row, 3.20 + i * 0.25, i));

  sectionDivider(s, "METRONIDAZOLE — Disulfiram Reactions + CYP Inhibition", 4.44, "145A32");
  tableHeader(s, 4.65);
  [
    ["Metronidazole", "Alcohol", "X", "Metronidazole inhibits acetaldehyde dehydrogenase → aldehyde accumulates (disulfiram-like reaction)", "Severe flushing, nausea, vomiting, tachycardia, hypotension (can be dangerous)", "CONTRAINDICATED. Avoid alcohol during and 48 hours after metronidazole. Warn patient explicitly. Tinidazole: same interaction"],
    ["Metronidazole", "Warfarin", "S", "CYP2C9 inhibition → warfarin (S-enantiomer) metabolism ↓", "INR ↑↑ → bleeding. Can double INR within days", "Reduce warfarin dose ~25–30%. Monitor INR at 3–5 days. Consider azithromycin or cephalosporins if alternatives for infection"],
    ["Metronidazole", "Lithium", "W", "Reduced renal lithium excretion (mechanism not fully elucidated)", "Lithium toxicity: tremor, ataxia, confusion, seizures", "Monitor lithium levels. Ensure good hydration. Check level at 5–7 days"],
    ["Metronidazole", "5-Fluorouracil (5-FU)", "M", "Metronidazole inhibits CYP2C9 → 5-FU clearance ↓", "5-FU toxicity: mucositis, myelosuppression, diarrhoea", "Avoid combination in oncology patients. Specialist review required"],
  ].forEach((row, i) => interactionRow(s, row, 4.87 + i * 0.25, i));

  sectionDivider(s, "RIFAMPICIN — Potent Enzyme INDUCER (opposite effect: ↓ drug levels)", 5.88, "78281F");
  tableHeader(s, 6.09);
  [
    ["Rifampicin", "Warfarin / DOACs (apixaban, rivaroxaban, edoxaban)", "X", "Rifampicin induces CYP3A4, CYP2C9, P-gp → anticoagulant levels ↓↓ dramatically", "Subtherapeutic anticoagulation → DVT, PE, stroke", "AVOID if possible. If essential for TB: use LMWH/UFH (not affected by CYP induction). DOAC levels decrease ≥50%"],
    ["Rifampicin", "Combined OCP / Progestogen pill", "X", "CYP3A4 induction → steroid contraceptive levels ↓↓↓", "Contraceptive failure → unplanned pregnancy", "Use IUD/IUS or DMPA injection. Continue barrier contraception for 28 days after stopping rifampicin"],
    ["Rifampicin", "HIV antiretrovirals (protease inhibitors, some NNRTIs)", "X", "Profound CYP3A4 induction → ART levels ↓↓ → virological failure", "HIV treatment failure, resistance emergence", "Replace rifampicin with rifabutin (weaker inducer) in HIV/TB co-infection. Specialist ID guidance essential"],
    ["Rifampicin", "Corticosteroids (prednisolone, dexamethasone)", "M", "CYP3A4 induction → steroid clearance ↑ → ↓ efficacy", "Loss of steroid effect (important in Addison's, transplant, IBD)", "Double or triple steroid dose during rifampicin. Monitor for adrenal crisis if steroid-dependent"],
  ].forEach((row, i) => interactionRow(s, row, 6.31 + i * 0.25, i));

  footer(s);
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 5 — CNS + PSYCHIATRIC INTERACTIONS
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  bg(s, 0, 0, 13.3, 7.5, C.offWhite);
  titleBar(s, "CNS + PSYCHIATRIC DRUG INTERACTIONS", "Slide 5 of 7", "3B0F5E");
  legendBar(s, 0.56);

  sectionDivider(s, "SEROTONIN SYNDROME — Life-threatening if missed", 0.82, "6E2C00");
  tableHeader(s, 1.03);
  [
    ["SSRIs / SNRIs (any)", "MAOIs (phenelzine, tranylcypromine, selegiline, linezolid, methylene blue)", "X", "MAOI prevents serotonin breakdown; SSRI/SNRI ↑ serotonin release → ↑↑↑ serotonin", "Serotonin syndrome: agitation, clonus, hyperreflexia, diaphoresis, hyperthermia → DEATH", "CONTRAINDICATED. Washout 14 days after stopping MAOI before starting SSRI. 5 weeks after fluoxetine (long t½). Linezolid is a reversible MAOI — avoid SSRIs"],
    ["SSRIs / SNRIs", "Tramadol", "S", "Tramadol inhibits serotonin reuptake + is weak opioid → serotonergic excess", "Serotonin syndrome (even at normal doses), seizures", "Avoid combination. Use alternative analgesia (paracetamol, codeine, morphine). If unavoidable: lowest tramadol dose, warn about symptoms"],
    ["SSRIs", "Triptans (sumatriptan, rizatriptan)", "W", "Both serotonergic → theoretical additive effect; regulatory warning issued 2006 (FDA/MHRA)", "Serotonin syndrome — evidence weak but real case reports exist", "FDA/MHRA advisory: monitor for serotonin syndrome symptoms. Clinical benefits usually outweigh risks (migraine in depression). Document discussion"],
    ["SSRIs / SNRIs", "Lithium", "W", "Additive serotonergic effects + lithium lowers seizure threshold", "Serotonin-like symptoms, neurotoxicity (even at therapeutic lithium levels)", "Monitor lithium levels. Reduce lithium dose. Educate patient. This combination is sometimes intentional (augmentation) — needs specialist oversight"],
    ["SSRIs (fluoxetine, fluvoxamine, paroxetine)", "Tamoxifen", "S", "Fluoxetine/paroxetine inhibit CYP2D6 → ↓ conversion of tamoxifen to active metabolite (endoxifen)", "Reduced tamoxifen efficacy → increased breast cancer recurrence", "Avoid fluoxetine, fluvoxamine, paroxetine in patients on tamoxifen. Use sertraline, citalopram, escitalopram, or venlafaxine (minimal CYP2D6 inhibition)"],
  ].forEach((row, i) => interactionRow(s, row, 1.25 + i * 0.25, i));

  sectionDivider(s, "ANTIEPILEPTICS — CYP450 Inducers (carbamazepine, phenytoin, phenobarbitone, primidone)", 2.52, "4A235B");
  tableHeader(s, 2.73);
  [
    ["Carbamazepine / Phenytoin / Phenobarb", "OCP / HRT (oestrogens)", "X", "CYP3A4 induction → sex steroid levels ↓", "Contraceptive failure / loss of menopausal symptom control", "Do not use OCP in enzyme-inducing AED patients. Use IUD/IUS/DMPA + barrier. Increase HRT dose under specialist guidance"],
    ["Carbamazepine / Phenytoin", "Warfarin / DOACs", "S", "CYP2C9/3A4 induction → anticoagulant levels ↓", "Subtherapeutic anticoagulation → thrombosis", "Monitor INR frequently. Higher warfarin doses required. DOACs unreliable — prefer LMWH or warfarin with careful INR monitoring"],
    ["Carbamazepine", "Carbamazepine + Erythromycin / Clarithromycin", "S", "Macrolides inhibit CYP3A4 → carbamazepine ↑↑ (autoinduction also makes levels unpredictable)", "Carbamazepine toxicity: diplopia, nausea, ataxia, seizures (paradoxically)", "Use azithromycin or doxycycline. Check carbamazepine level if macrolide unavoidable"],
    ["Sodium Valproate", "Lamotrigine", "M", "Valproate inhibits glucuronidation (UGT enzymes) → lamotrigine half-life doubles", "Lamotrigine toxicity: rash, diplopia, dizziness, Stevens-Johnson syndrome", "Halve lamotrigine dose when starting valproate. Titrate very slowly. Standard lamotrigine dose causes toxicity when combined with valproate"],
    ["Phenytoin", "Multiple drugs (warfarin, ciclosporin, doxycycline, methotrexate, many more)", "M", "CYP2C9/CYP3A4 induction + phenytoin itself is a substrate → highly variable + multiple interactions", "Variable: loss of efficacy of co-administered drugs", "Phenytoin is a 'problem drug'. Check all co-medications in BNF. Therapeutic drug monitoring essential (narrow TI, non-linear kinetics)"],
  ].forEach((row, i) => interactionRow(s, row, 2.95 + i * 0.25, i));

  sectionDivider(s, "LITHIUM — Narrow Therapeutic Index (0.6–1.0 mmol/L), Multiple Renal Interactions", 4.22, "154360");
  tableHeader(s, 4.43);
  [
    ["Lithium", "NSAIDs (Ibuprofen, Diclofenac, Naproxen)", "S", "NSAIDs ↓ renal prostaglandins → ↓ GFR → ↓ lithium excretion → lithium ↑", "Lithium toxicity: coarse tremor, vomiting, confusion, seizures, coma, renal failure", "AVOID NSAIDs in lithium patients. Use paracetamol. If inadvertent NSAID use: check lithium level immediately. Educate patients"],
    ["Lithium", "ACE inhibitors / ARBs", "M", "↓ renal perfusion → ↓ lithium clearance", "Lithium toxicity (can occur within days of starting ACEi/ARB)", "Monitor lithium level 1 week after starting. Reduce lithium dose. Common combination in bipolar + hypertension — needs monitoring"],
    ["Lithium", "Thiazide diuretics (Bendroflumethiazide, Indapamide)", "M", "Thiazides → sodium depletion → compensatory ↑ renal Na+ (and Li+) reabsorption", "Lithium toxicity (even standard doses)", "Avoid thiazides. Use loop diuretics (furosemide) if diuretic needed — safer with lithium. Monitor levels frequently"],
    ["Lithium", "SSRIs + Serotonergic drugs", "W", "Additive serotonergic effects", "Serotonin-like toxicity, neurotoxicity", "Monitor for serotonin-like features. Check lithium levels. Reduce doses if symptoms arise"],
  ].forEach((row, i) => interactionRow(s, row, 4.65 + i * 0.25, i));

  sectionDivider(s, "ANTIPSYCHOTICS — QT Prolongation, Sedation, Extrapyramidal", 5.68, "4A235B");
  tableHeader(s, 5.89);
  [
    ["Haloperidol / Quetiapine / Clozapine", "Any QT-prolonging drug (clarithromycin, ondansetron, methadone, amiodarone, fluconazole)", "S", "Additive blockade of hERG cardiac K+ channels → QT ↑↑", "Torsades de Pointes → VF, sudden death", "Check CredibleMeds database for all QT drugs. Mandatory ECG before prescribing. Correct K+/Mg2+. Avoid combining high-risk QT agents"],
    ["Clozapine", "Ciprofloxacin / Fluvoxamine", "S", "CYP1A2 inhibition → clozapine AUC ↑ 2–3×", "Clozapine toxicity: seizures, hypotension, agranulocytosis risk ↑, sedation", "Avoid ciprofloxacin + clozapine. Use trimethoprim or amoxicillin for UTI. Monitor clozapine level + FBC"],
    ["Antipsychotics (any)", "Metoclopramide / Domperidone", "M", "Additive dopamine D2 blockade in nigrostriatal pathway", "Extrapyramidal side-effects: acute dystonia, akathisia, parkinsonism, risk of tardive dyskinesia", "Avoid combination especially long-term. Use ondansetron or cyclizine for nausea in antipsychotic-treated patients"],
    ["Clozapine", "Smoking cessation (stopping smoking)", "M", "Smoking induces CYP1A2 → clozapine metabolised faster; stopping → CYP1A2 activity ↓ → clozapine ↑", "Clozapine toxicity when patient stops smoking (e.g., hospital admission, NRT)", "Reduce clozapine dose by ~25% when stopping smoking. Monitor levels. Restart dose increase if smoking resumes"],
  ].forEach((row, i) => interactionRow(s, row, 6.11 + i * 0.25, i));

  footer(s);
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 6 — ENDOCRINE + RENAL INTERACTIONS
// ══════════════════════════════════════════════════════════════════════════════
{
  const s = pres.addSlide();
  bg(s, 0, 0, 13.3, 7.5, C.offWhite);
  titleBar(s, "ENDOCRINE + RENAL DRUG INTERACTIONS", "Slide 6 of 7", "6E2F0A");
  legendBar(s, 0.56);

  sectionDivider(s, "DIABETES DRUGS — Hypoglycaemia, Lactic Acidosis, Interaction with Common Co-medications", 0.82, "6E2F0A");
  tableHeader(s, 1.03);
  [
    ["Metformin", "IV Contrast media (iodinated)", "S", "Contrast → transient renal impairment → metformin accumulates → lactic acidosis (rare but serious)", "Metformin-associated lactic acidosis (MALA) — high mortality", "HOLD metformin on day of contrast procedure + 48 hours after. Restart only if eGFR stable at 48h check. MHRA guidance 2020"],
    ["Metformin", "Alcohol (chronic excess)", "M", "Alcohol → hepatic impairment + ↑ lactate production → additive lactic acidosis risk", "Lactic acidosis", "Counsel patients to avoid binge/heavy drinking. Moderate intake generally acceptable. Monitor LFTs"],
    ["Sulfonylureas (Gliclazide, Glibenclamide)", "Fluconazole", "S", "Fluconazole inhibits CYP2C9 → sulfonylurea AUC ↑ significantly", "Severe hypoglycaemia (can last hours due to long t½ of drug)", "Reduce sulfonylurea dose. Monitor glucose frequently. Consider hospital admission for severe hypo. Use topical antifungal if possible"],
    ["Sulfonylureas", "Beta-blockers", "W", "Beta-blockers mask adrenergic hypoglycaemia warning symptoms (palpitations, tremor); diaphoresis preserved", "Unrecognised hypoglycaemia → severe prolonged episode", "Counsel patient — rely on sweating symptom. Cardioselective BB slightly safer. More frequent glucose monitoring"],
    ["Insulin", "Corticosteroids (prednisolone, dexamethasone)", "W", "Steroids → insulin resistance + stimulate hepatic gluconeogenesis → hyperglycaemia, especially post-prandial", "Loss of glycaemic control; steroid-induced hyperglycaemia", "Increase insulin dose (often need +20–50% or more). Monitor 4-times daily glucose. Use variable rate IV insulin if nil by mouth. STOP extra insulin when steroids stop"],
    ["SGLT2 inhibitors (empagliflozin, dapagliflozin)", "Loop diuretics (furosemide)", "W", "Both cause natriuresis/osmotic diuresis → additive volume depletion", "Dehydration, AKI, hypotension (especially in elderly)", "Monitor renal function and BP. Educate patient on sick-day rules: STOP SGLT2i if acutely unwell/dehydrated. Hold before surgery"],
    ["SGLT2 inhibitors", "Insulin / Sulfonylurea", "W", "SGLT2i may lower glucose further when combined with insulin/SU", "Hypoglycaemia (more common when combined)", "Reduce insulin or SU dose by ~20% when initiating SGLT2i. Monitor glucose. Risk of euglycaemic DKA with insulin + SGLT2i combination"],
  ].forEach((row, i) => interactionRow(s, row, 1.25 + i * 0.25, i));

  sectionDivider(s, "IMMUNOSUPPRESSANTS (Ciclosporin / Tacrolimus) — Narrow TI, Multiple Interactions", 3.02, "154360");
  tableHeader(s, 3.23);
  [
    ["Ciclosporin / Tacrolimus", "Clarithromycin / Erythromycin / Azole antifungals", "X", "CYP3A4 inhibition → immunosuppressant AUC ↑ 2–5×", "Severe nephrotoxicity, neurotoxicity, transplant rejection if stopped abruptly", "CONTRAINDICATED. If antifungal needed: use liposomal amphotericin or specialist azole dosing with daily drug level monitoring"],
    ["Ciclosporin / Tacrolimus", "Rifampicin", "X", "CYP3A4 induction → immunosuppressant levels ↓↓ up to 70%", "Acute transplant rejection, graft loss", "AVOID. If TB treatment essential: replace rifampicin with rifabutin (weaker inducer). Multiple daily drug level checks needed"],
    ["Ciclosporin", "NSAIDs", "S", "Additive nephrotoxicity (both reduce renal prostaglandins/GFR)", "AKI in transplant patients", "AVOID NSAIDs in ciclosporin-treated patients. Use paracetamol. Monitor eGFR closely if unavoidable"],
    ["Ciclosporin", "Statins (see slide 2)", "S", "OATP1B1/MRP2 inhibition → statin AUC ↑↑", "Rhabdomyolysis", "Limit rosuvastatin ≤5 mg/day, pravastatin ≤20 mg/day. Avoid simvastatin/lovastatin. Monitor CK"],
    ["Tacrolimus", "Potassium-sparing agents (ACEi, ARB, spironolactone)", "M", "Tacrolimus → hyperkalaemia (direct tubular effect) + additive with K+-retaining agents", "Severe hyperkalaemia → arrhythmia", "Monitor K+ weekly initially. Target K+ <5.0. Avoid ACEi/ARB/spironolactone combination unless essential + closely monitored"],
  ].forEach((row, i) => interactionRow(s, row, 3.45 + i * 0.25, i));

  sectionDivider(s, "DIURETICS — Electrolyte Disturbances + Interactions", 4.72, "1A5276");
  tableHeader(s, 4.93);
  [
    ["Furosemide / Thiazides (loop + thiazide diuretics)", "Gentamicin / Vancomycin (aminoglycosides)", "S", "Loop diuretics enhance aminoglycoside-induced cochlear endolymph damage + share nephrotoxicity", "Ototoxicity (sensorineural hearing loss — IRREVERSIBLE) + AKI", "Avoid concurrent use where possible. If essential: ensure normovolaemia, monitor U&E daily, audiological assessment, target lowest effective aminoglycoside dose"],
    ["Loop / Thiazide diuretics", "Digoxin", "M", "Diuretic-induced hypokalaemia + hypomagnesaemia → ↑ digoxin binding at Na+/K+-ATPase", "Digoxin toxicity at therapeutic levels", "Maintain K+ >4.0 mmol/L. Replace Mg2+ if deficient. Monitor digoxin level and ECG"],
    ["Loop / Thiazide diuretics", "Lithium", "M", "Sodium depletion → compensatory proximal tubular Li+ reabsorption ↑", "Lithium toxicity", "Avoid thiazides with lithium. Furosemide safer if diuretic needed (loop diuretics act on distal tubule). Monitor Li+ levels weekly initially"],
    ["Furosemide", "NSAIDs", "M", "NSAIDs ↓ renal prostaglandins → blunt diuretic-induced GFR protection + ↓ natriuresis", "Reduced diuretic efficacy ('diuretic resistance'), AKI risk (triple whammy with ACEi)", "Avoid regular NSAIDs. Paracetamol for analgesia. Weigh patient daily; warn to avoid NSAID OTC purchases"],
  ].forEach((row, i) => interactionRow(s, row, 5.15 + i * 0.25, i));

  sectionDivider(s, "CORTICOSTEROIDS — Multiple Important Interactions", 6.16, "6E2F0A");
  tableHeader(s, 6.37);
  [
    ["Prednisolone / Dexamethasone", "NSAIDs (Ibuprofen, Naproxen, Diclofenac)", "S", "Additive gastropathy: both damage gastric mucosa via prostaglandin suppression and direct mucosal damage", "GI bleeding, perforation, peptic ulceration", "AVOID combination. If both needed: add PPI (lansoprazole/omeprazole). Use paracetamol for analgesia. Higher-dose steroids especially risky"],
    ["Prednisolone / Dexamethasone", "Rifampicin", "M", "CYP3A4 induction → steroid clearance ↑ → ↓ efficacy", "Adrenal crisis if steroid-dependent, loss of treatment effect in IBD/RA etc.", "Double or triple steroid dose. Critical in Addison's or transplant. Monitor for loss of control of underlying disease"],
    ["Prednisolone", "Live vaccines (MMR, varicella, BCG, yellow fever)", "X", "Immunosuppression → normal vaccine virus replication → disseminated infection", "Systemic live vaccine infection — potentially fatal", "CONTRAINDICATED in patients on prednisolone ≥40 mg/day or >1 mg/kg for >1 week. Inactivated/killed vaccines safe"],
  ].forEach((row, i) => interactionRow(s, row, 6.59 + i * 0.25, i));

  footer(s);
}

// ══════════════════════════════════════════════════════════════════════════════
// SLIDE 7 — HIGH-RISK PAIRS AT A GLANCE (Summary matrix)
// ══════════════════════════════════════════════════════════════════════════════
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  // Each card: coloured left strip, drug pair, consequence, action

  const CARDS = [
    // [sev, drugA, drugB, consequence, action]
    ["X", "Simvastatin / Lovastatin", "Clarithromycin / Erythromycin",         "Rhabdomyolysis",                    "Use azithromycin OR switch to pravastatin/rosuvastatin"],
    ["X", "SSRIs / SNRIs",            "MAOIs (inc. Linezolid)",                 "Serotonin Syndrome → DEATH",        "14-day washout. Linezolid is a reversible MAOI"],
    ["X", "Warfarin",                  "Fluconazole",                            "INR ↑↑↑ → major bleeding",          "Avoid. If essential: LMWH bridge. Topical miconazole can also interact"],
    ["X", "Warfarin",                  "Amiodarone",                             "INR doubles; persists months",      "Reduce warfarin 30–50%, daily INR monitoring. Consider DOAC"],
    ["X", "Verapamil / Diltiazem",    "Beta-blockers",                          "Complete heart block, asystole",    "CONTRAINDICATED (especially IV verapamil). Use amlodipine if CCB needed"],
    ["X", "Rifampicin",               "DOACs (apixaban, rivaroxaban)",          "DOAC levels ↓↓ → thrombosis",       "Use LMWH/warfarin instead. Rifabutin if TB Rx needed in HIV"],
    ["X", "Colchicine",               "Clarithromycin (renal impairment)",      "Multi-organ failure, death",        "Use azithromycin. Max colchicine 0.5 mg if macrolide unavoidable"],
    ["X", "Metronidazole",            "Alcohol",                                "Disulfiram reaction (severe)",      "No alcohol during and 48h after. Warn patient explicitly"],
    ["X", "Ciclosporin / Tacrolimus", "Rifampicin",                             "Transplant rejection",              "Avoid. Use rifabutin + intensive drug level monitoring"],
    ["X", "OCP",                      "Rifampicin / Enzyme-inducing AEDs",      "Contraceptive failure",             "Use LARC (IUD/IUS). Continue barrier 28 days after stopping rifampicin"],
    ["S", "ACE inhibitor / ARB",      "NSAIDs + Diuretic (Triple Whammy)",      "Acute kidney injury",               "Avoid NSAIDs. Sick-day rules: STOP all 3 if unwell/dehydrated"],
    ["S", "Amiodarone",               "Any QT-prolonging drug",                 "Torsades de Pointes → VF",          "Check CredibleMeds. ECG + electrolytes before any QT drug"],
    ["S", "Digoxin",                  "Amiodarone / Verapamil / Diltiazem",     "Digoxin toxicity",                  "Reduce digoxin by 30–50%. Monitor levels + ECG"],
    ["S", "Lithium",                  "NSAIDs",                                 "Lithium toxicity",                  "AVOID NSAIDs. Use paracetamol. Check level immediately if inadvertent use"],
    ["S", "Metformin",                "IV contrast",                            "Lactic acidosis (MALA)",            "Hold metformin day of procedure + 48h. Restart only if eGFR stable"],
    ["S", "SSRIs (fluoxetine/parox)", "Tamoxifen",                              "Reduced tamoxifen efficacy → cancer recurrence", "Use sertraline/citalopram/escitalopram instead. Avoid CYP2D6-inhibiting SSRIs"],
    ["M", "Beta-blocker",             "Insulin / Sulfonylurea",                 "Masked hypoglycaemia",              "Counsel patient. Cardioselective BB safer. Rely on sweating symptom"],
    ["M", "Valproate",                "Lamotrigine",                            "Lamotrigine toxicity (SJS risk)",   "Halve lamotrigine starting dose. Titrate very slowly"],
    ["M", "Corticosteroids",          "NSAIDs",                                 "GI bleeding / perforation",         "PPI cover mandatory. Use paracetamol for analgesia where possible"],
    ["M", "Ciprofloxacin",            "Theophylline",                           "Theophylline toxicity",             "Reduce theophylline dose 30–50% or use amoxicillin instead"],
    ["M", "Clozapine",                "Stopping smoking",                       "Clozapine toxicity",                "Reduce clozapine ~25% on admission. Monitor levels. Reincrease if smoking resumes"],
    ["W", "SGLT2 inhibitor",          "Acute illness / surgery",                "Euglycaemic DKA",                   "SICK DAY RULES: STOP SGLT2i if acutely unwell, fasting, or before surgery"],
    ["W", "Antipsychotics",           "Metoclopramide / Domperidone",           "Extrapyramidal SE ↑↑",              "Use ondansetron or cyclizine for nausea in antipsychotic-treated patients"],
    ["W", "Fluoroquinolone",          "Oral iron / antacids",                   "↓ antibiotic absorption (75%)",     "Take fluoroquinolone 2h before or 4h after iron/antacids"],
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  const legLabels = ["CONTRAINDICATED","SERIOUS","MAJOR","MODERATE","MONITOR"];
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  // Column headers
  bg(s, col1X, 0.80, 6.5, 0.22, C.hdrBg);
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  bg(s, col2X, 0.80, 6.5, 0.22, C.hdrBg);
  txt(s, "Drug A + Drug B  →  Consequence  →  Action", col2X + 0.15, 0.80, 6.3, 0.22, { color: C.white, sz: 7.5, bold: true, valign: "middle" });

  CARDS.forEach((card, i) => {
    const [sev, a, b, consequence, action] = card;
    const cfg = SEV[sev];
    const col = i < half ? 0 : 1;
    const rowIdx = i < half ? i : i - half;
    const x = col === 0 ? col1X : col2X;
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    // Row background
    bg(s, x, y, 6.5, cardH, rowBg);
    // Left severity stripe
    bg(s, x, y, 0.14, cardH, cfg.bg);
    // Drug pair
    txt(s, `${a} + ${b}`, x + 0.17, y, 2.3, cardH, { sz: 7.2, bold: true, color: C.navy, margin: 2 });
    // Arrow separator
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    // Arrow 2
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// ──────────────────────────────────────────────────────────────────────────────
pres.writeFile({ fileName: "/home/daytona/workspace/drug-cheatsheet/Drug_Interactions_QuickRef.pptx" })
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