Amlodipine - Adverse Drug Reactions

Common / Dose-Related ADRs

• Harrison's Principles of Internal Medicine 22E lists amlodipine's main side effects as headache and edema
• Tintinalli's Emergency Medicine notes: hypotension, peripheral edema, headache, palpitations, and flushing
• The Harriet Lane Handbook specifies: "dose-related side effects include edema, dizziness, flushing, fatigue, and palpitations"

Why Less Reflex Tachycardia Than Short-Acting DHPs

Important Considerations

• Gingival hyperplasia - a class effect of calcium channel blockers (especially seen with nifedipine; less common with amlodipine)
• Do not combine with beta-blockers if verapamil/diltiazem - note this warning is specific to non-DHP CCBs; amlodipine CAN be safely combined with beta-blockers
• In CKD patients: there is evidence that dihydropyridine CCBs may allow greater transmission of systemic blood pressure to the glomerulus, potentially affecting CKD progression

Metformin - Adverse Drug Reactions

1. Gastrointestinal ADRs (Most Common)

• Nausea, vomiting
• Diarrhea
• Anorexia / loss of appetite (can contribute to mild weight loss)
• Abdominal cramping, bloating, indigestion
• Metallic taste / dysgeusia
• In 3-5% of patients, GI effects are persistent enough to require drug discontinuation

2. Lactic Acidosis (Rare but Potentially Fatal)

• Mechanism: metformin inhibits hepatic mitochondrial complex I, reducing lactate clearance and increasing lactate production. In states of tissue hypoxia, lactate can accumulate fatally.
• Almost always occurs with concurrent risk factors:
  • Renal failure (reduced metformin clearance - levels rise when CrCl <40-50 mL/min)
  • Acute MI, sepsis, severe heart failure, liver failure, respiratory failure, alcoholism
• Metformin is contraindicated when eGFR <30 mL/min/1.73 m², and dose-reduced for eGFR 30-45
• Hold metformin on day of IV radiocontrast administration; restart 48h later after confirming renal function is stable

3. Vitamin B12 Deficiency

• Chronic metformin use is associated with 20-30% lower blood levels of vitamin B12
• Mechanism: metformin interferes with calcium-dependent absorption of the vitamin B12-intrinsic factor complex in the terminal ileum. Increased calcium intake may prevent this.
• Can cause: peripheral neuropathy, macrocytic anemia
• Periodic B12 monitoring is recommended, especially in patients with neuropathy or anemia

4. What Metformin Does NOT Cause

• Hypoglycemia (does not stimulate insulin secretion - a key advantage)
• Weight gain (neutral or mild weight reduction)

Summary Table

Patient Counselling

👋 Introduction

💊 AMLODIPINE - What You Need to Know

What is it for?

How to take it

• Take it once daily, at the same time every day
• You can take it with or without food
• If you miss a dose, take it as soon as you remember - but if it is almost time for your next dose, skip the missed dose (never double up)

What you may feel - Common Side Effects

• This is the most common side effect
• It happens because the medicine relaxes blood vessels, causing some fluid to collect in the legs
• What to do: Keep your legs elevated when resting; wear comfortable footwear. If the swelling becomes severe or spreads to your face, call your doctor

• Your face or neck may feel warm or look red, especially when you first start the medicine
• This usually settles down after a few weeks
• What to do: Stay in a cool environment; this effect typically goes away on its own

• Mild headaches are common in the first week as your blood vessels adjust
• What to do: A mild painkiller (like paracetamol) can help. If headaches are severe or do not go away, inform your doctor

• You may feel lightheaded, especially when standing up quickly
• What to do: Rise slowly from sitting or lying positions. Hold onto something for support. Avoid driving if you feel dizzy.

• You may occasionally feel your heart beating faster
• This is usually mild and settles on its own
• What to do: If your heart is racing fast or you feel chest pain along with palpitations, seek medical attention immediately

Important Warnings - Amlodipine

• Do NOT stop this medicine suddenly without telling your doctor - your blood pressure may spike
• Avoid grapefruit juice - it can increase the drug level in your blood and worsen side effects
• Tell your doctor if you are pregnant or planning to become pregnant

💊 METFORMIN - What You Need to Know

What is it for?

How to take it

• Take it with meals or immediately after eating - this is very important to reduce stomach upset
• Start with a low dose; your doctor will increase it gradually
• Swallow tablets whole with a full glass of water

What you may feel - Common Side Effects

• This is the most common complaint, especially in the first 2-4 weeks
• Affects up to 1 in 4 patients when starting the medicine
• What to do:
  • Always take with food - never on an empty stomach
  • Start with the lowest dose and let your body adjust
  • Eat smaller, more frequent meals
  • The symptoms almost always improve after 2-4 weeks
  • Ask your doctor about the extended-release version if symptoms persist

• Some patients notice food tastes different, or they feel less hungry
• This is harmless and usually temporary
• What to do: Maintain regular meals; do not skip meals as your blood sugar may drop too low

• Unlike some diabetes medicines, metformin does not cause weight gain and may cause slight weight loss - this is actually a benefit for most patients

Serious but Rare Side Effect - Lactic Acidosis

• Unusual muscle pain or weakness
• Difficulty breathing
• Stomach pain with nausea and vomiting
• Feeling cold, dizzy, or faint
• Slow or irregular heartbeat

• If you drink large amounts of alcohol regularly - avoid excessive alcohol
• If you become seriously ill with fever, vomiting, or dehydration - stop metformin temporarily and call your doctor
• If you need a CT scan or X-ray with dye (contrast injection) - tell your doctor you are on metformin - it must be stopped before the procedure and restarted 48 hours later

Long-Term Effect - Vitamin B12 Deficiency

• Taking metformin for many years can slowly reduce your Vitamin B12 levels
• Low B12 can cause tingling or numbness in hands and feet, memory problems, and anemia
• What to do: Your doctor will check your B12 level once a year. Eat foods rich in B12 (meat, eggs, dairy, fish). Supplements may be prescribed if needed.

Important Warnings - Metformin

• Do NOT skip meals when on metformin - maintain regular eating patterns
• Do NOT drink excessive alcohol - increases lactic acidosis risk
• Inform your doctor or dentist before any surgical procedure or fasting procedure
• Metformin does NOT cause low blood sugar (hypoglycemia) on its own - but if combined with other diabetes medicines, it might

🔁 Taking Both Medicines Together

• Take Amlodipine at a fixed time daily (e.g., morning)
• Take Metformin with breakfast and dinner (if twice daily)
• Attend all your follow-up appointments so your doctor can monitor your blood pressure, blood sugar, kidney function, and B12 levels

🚨 When to Contact Your Doctor Urgently

✅ Key Points to Remember

1. Take Amlodipine once daily - same time every day
2. Take Metformin with food - never on an empty stomach
3. Do not stop either medicine without telling your doctor
4. Avoid grapefruit juice (Amlodipine) and excessive alcohol (Metformin)
5. Tell any doctor or radiologist that you are on Metformin before a contrast scan
6. Get your B12 levels, kidney function, and blood pressure checked regularly
7. If you feel unusually unwell - especially with vomiting, fever, or muscle pain - contact your doctor and temporarily pause Metformin

Patient Counselling: NSAID Abuse / Overuse

👋 Opening the Conversation

💊 What Are NSAIDs?

• Ibuprofen (Brufen, Advil)
• Diclofenac (Voveran, Voltaren)
• Naproxen (Naprosyn)
• Aspirin (in higher doses used as a pain reliever)
• Ketorolac (Toradol)
• Celecoxib (Celebrex - a COX-2 type)

⚠️ What NSAID Abuse Does to Your Body

1. 🫁 Stomach and Gut (Most Common)

• Dyspepsia, heartburn, and nausea are the most common early warning signs
• Bleeding can occur silently - no pain until it becomes serious
• Risk is higher in: elderly patients, those who drink alcohol, those also on steroids or blood thinners

• Always take NSAIDs with food or milk
• Never take on an empty stomach
• Your doctor may prescribe a stomach-protective medicine (like omeprazole or pantoprazole) alongside NSAIDs
• If you notice black stools or vomit blood - go to the emergency department immediately

2. 🫀 Heart and Blood Vessels

• Increases risk of heart attack and stroke
• The greatest risk for heart attack occurs within the first month of NSAID use, especially at higher doses
• Risk is significantly higher in patients who already have heart disease, high blood pressure, or diabetes
• NSAIDs cause fluid and sodium retention, which raises blood pressure and strains the heart

• If you have heart disease or high blood pressure, do not self-medicate with NSAIDs
• For patients over 75, prefer topical NSAID gels (applied to skin) over oral tablets - same pain relief with far less risk
• If NSAIDs are necessary, use the lowest dose for the shortest time possible

3. 🫘 Kidneys

• Acute kidney injury - especially if you are dehydrated, have existing kidney disease, or are elderly
• Sodium and water retention - causing swelling in legs, raised blood pressure
• Interstitial nephritis - a type of kidney inflammation (hypersensitivity reaction)
• Chronic kidney damage with prolonged overuse (analgesic nephropathy)

• Reduced urine output
• Swelling in legs and face
• Fatigue, confusion
• Blood in urine

• Drink adequate water daily
• Do not take NSAIDs when you are vomiting, have diarrhea, or are dehydrated
• Get your kidney function (serum creatinine, eGFR) checked if you use NSAIDs regularly
• People with kidney disease should avoid NSAIDs entirely

4. 🧠 Medication Overuse Headache (Rebound Headache)

• Using NSAIDs (or any painkiller) for headache more than 10-15 days per month leads to a condition called Medication Overuse Headache (MOH) - also called rebound headache
• The headaches become daily or near-daily, worse in the morning, and stop responding to the medicine
• The only cure is to gradually reduce and stop the overused painkiller - this causes temporary worsening before improvement

• Keep a headache diary - note how often you take painkillers
• If you are using painkillers more than 10 days a month, tell your doctor
• Reduce the dose by about 10% every 1-2 weeks under guidance
• A preventive medicine for headaches may be started at the same time

5. 🫁 Lungs

• NSAIDs can trigger bronchospasm (asthma attacks) in susceptible patients
• This is called aspirin-exacerbated respiratory disease and can occur with all NSAIDs, not just aspirin
• Can also rarely cause hypersensitivity pneumonitis (lung inflammation)

• If you have asthma, always inform your doctor before taking any NSAID
• If you notice wheezing, chest tightness, or shortness of breath after taking an NSAID - stop immediately and seek help

6. 🩸 Blood and Liver

• NSAIDs interfere with platelet function - increasing bleeding risk (wounds, surgery, dental procedures)
• Can elevate liver enzymes - in rare cases lead to liver injury
• Rare but serious blood reactions: aplastic anemia, agranulocytosis

• Always tell your surgeon or dentist that you take NSAIDs - they may need to stop them before procedures
• Get liver function tests checked if you are on long-term NSAIDs

7. 🤰 Pregnancy Warning

• Can cause premature closure of the ductus arteriosus (a blood vessel in the unborn baby's heart)
• Can reduce amniotic fluid (oligohydramnios)
• Can slow uterine contractions
• Avoid NSAIDs entirely from 20 weeks of pregnancy onwards - use paracetamol instead

🚨 When to Seek Immediate Help

✅ Safer Pain Management Alternatives

📋 Golden Rules for Safe NSAID Use

1. Never take NSAIDs on an empty stomach - always with food
2. Use the lowest effective dose for the shortest possible time
3. Do not combine two NSAIDs - this doubles the risk with no added benefit
4. Do not mix NSAIDs with alcohol - greatly increases stomach bleeding risk
5. Do not self-medicate for more than 3-5 days without medical advice
6. Tell your doctor if you have: kidney disease, heart disease, stomach ulcers, asthma, or are pregnant
7. Get regular monitoring if you need long-term NSAIDs: kidney function, blood pressure, stool for occult blood

💬 Closing

Source references: Tintinalli's Emergency Medicine (NSAID Toxicity Table); Robbins Pathologic Basis of Disease (NSAID Nephropathy); Harrison's Principles of Internal Medicine 22E (Medication Overuse Headache); Lippincott Illustrated Reviews Pharmacology; Goodman & Gilman's Pharmacological Basis of Therapeutics

Topical NSAIDs - Complete Overview

What Are Topical NSAIDs?

Available Formulations

Mechanism of Action

• Topical NSAIDs work by the same mechanism as oral NSAIDs - inhibiting cyclooxygenase (COX-1 and COX-2) enzymes, thereby reducing prostaglandin synthesis at the site of pain and inflammation
• They act on peripheral tissue prostaglandin synthesis - reducing local pain, swelling, and inflammation
• The drug penetrates through skin layers to reach subcutaneous tissue, joint capsule, synovial fluid, and periarticular structures

Pharmacokinetics - Why Topical Is Safer

Systemic Absorption

• Systemic bioavailability of topical diclofenac is only about 6-10% of the equivalent oral dose
• Studies comparing oral vs. topical diclofenac confirmed significantly lower systemic plasma levels with topical use
• The drug accumulates in synovial fluid after topical application (similar to oral route), explaining its sustained local effect despite low blood levels

Penetration Factors

• Vehicle/base: Gel, cream, solution, and patch formulations differ in penetration efficiency
• Site of application: Thinner skin (hands, knees) allows better penetration than thick skin
• Hydration of skin: Moist skin absorbs better
• Molecular size of the NSAID
• Temperature: Warm skin has greater penetration (explains why heat packs enhance topical drug effect)
• Occlusion: Covering with a bandage after application increases absorption

Clinical Uses

1. Osteoarthritis (OA) - Primary Indication

• Topical NSAIDs have demonstrated efficacy over placebo for knee and hand OA pain and function
• Efficacy is generally similar to oral NSAIDs for superficial joints
• In meta-analyses:
  • Diclofenac patch - greatest efficacy for pain
  • Piroxicam gel - greatest benefit for functional improvement
• The 2019 ACR (American College of Rheumatology) OA guidelines strongly recommend topical NSAIDs for knee OA
• Particularly preferred in elderly patients as the first-line pharmacological treatment due to the superior safety profile
• Note: Evidence for deeper joints (hip, shoulder OA) is lacking - topical NSAIDs may not penetrate deeply enough for these

2. Musculoskeletal Injuries

• Acute sprains, strains, and bruises
• Tendinitis, bursitis
• Sports injuries
• Post-exercise muscle soreness

3. Dermatological Use

• Diclofenac 3% gel is specifically indicated for actinic keratosis (pre-cancerous sun-damaged skin lesions) - used twice daily for 60-90 days

4. Ophthalmic Use

• Ketorolac eye drops - used for:
  • Seasonal allergic conjunctivitis
  • Post-cataract surgery inflammation and pain
  • Pain and photophobia after corneal refractive surgery
• Diclofenac ophthalmic solution - postoperative inflammation after cataract surgery

5. Counterirritant Topicals (Salicylates)

• Methyl salicylate (oil of wintergreen) - used in arthritis creams and sports rubs as a cutaneous counterirritant; produces warmth and mild local analgesia
• Salicylic acid - topical treatment of acne, corns, calluses, warts (keratolytic effect, not anti-inflammatory)

Advantages Over Oral NSAIDs

Adverse Effects

Local (More Common)

• Dry skin at application site
• Erythema (redness)
• Skin irritation / burning sensation
• Paresthesia (tingling, numbness)
• Pruritus (itching)
• Contact dermatitis (hypersensitivity reaction)
• Photosensitivity - especially with ketoprofen gel (avoid sun exposure on treated area)

Systemic (Much Less Common Than Oral)

• Despite low systemic absorption, occasional GI side effects and headaches have been reported
• Anemia, renal abnormalities, and hepatic effects seen with oral NSAIDs are much less common but not entirely absent

How to Apply - Correct Technique

1. Wash and dry the affected area first
2. Apply the measured amount as directed (often measured in finger-tip units or cm of gel squeezed from tube)
3. Gently rub in using light circular motions until absorbed
4. Do not cover with airtight dressings unless specifically instructed (occlusion increases systemic absorption)
5. Wait for absorption before clothing covers the area - do not wipe off the gel too soon
6. Wash hands after application (unless treating hands)
7. Do not apply to broken, abraded, infected, or eczematous skin
8. Avoid eyes and mucous membranes
9. Do not apply over heat pads, ultrasound gel, or tight bandages simultaneously (increases absorption unpredictably)

Contraindications / Precautions

• Known hypersensitivity to NSAIDs (aspirin-exacerbated respiratory disease - risk of systemic reaction even from topical)
• Do not apply to open wounds, broken skin, or infected areas
• Avoid use in third trimester of pregnancy
• Ketoprofen gel - avoid sun exposure on treated skin (photosensitivity risk)
• Do not use with occlusive dressings unless directed
• Keep away from eyes and mucous membranes

Key Clinical Points

• Topical NSAIDs are the first-line pharmacological option for knee and hand OA (2019 ACR guidelines), especially in elderly patients
• They are the preferred alternative for patients who cannot tolerate oral NSAIDs due to GI problems, renal impairment, cardiovascular disease, or advanced age
• The drug must reach the joint - efficacy is limited for deep joints like hip and shoulder
• Diclofenac is the most studied and widely used topical NSAID
• The diclofenac + misoprostol oral combination serves a similar GI-protective purpose for patients needing oral NSAIDs who are at high GI risk

Sources: Goodman & Gilman's Pharmacological Basis of Therapeutics; Firestein & Kelley's Textbook of Rheumatology (2-Volume Set); Lippincott Illustrated Reviews Pharmacology; Tintinalli's Emergency Medicine

Management of Mild Erosive Oesophagitis in GERD

Understanding "Mild" Erosive Oesophagitis

Step 1 - Lifestyle Modifications (Foundation of All GERD Treatment)

Dietary Changes

• Avoid acidic foods - citrus fruits, tomato-based products
• Avoid chocolate, peppermint, onions, garlic (reduce lower oesophageal sphincter tone)
• Avoid alcohol (irritates oesophageal mucosa and reduces LOS pressure)
• Avoid caffeinated beverages (coffee, tea, cola)
• Reduce dietary fat (fatty meals delay gastric emptying and relax LOS)
• Eat smaller, more frequent meals - avoid large meals
• Do not eat within 3-4 hours of lying down

Positional / Behavioural

• Elevate the head of the bed 4-8 inches (10-20 cm) using a wedge - most effective positional measure; prevents nocturnal reflux
• Avoid tight clothing around the waist (increases intra-abdominal pressure)
• Avoid recumbency within 3-4 hours after meals
• Avoid bending over or stooping after meals

Weight and Habits

• Lose weight - obesity increases intra-abdominal pressure and is a strong risk factor for GERD
• Stop smoking - nicotine reduces LOS pressure and impairs mucosal healing
• Reduce alcohol - direct mucosal irritant

Medications to Avoid

• Calcium channel blockers (e.g., amlodipine, nifedipine)
• Beta-agonists, alpha-agonists
• Theophylline
• Nitrates
• Sedatives / benzodiazepines
• Anticholinergics

Step 2 - Pharmacological Therapy

A. Proton Pump Inhibitors (PPIs) - First-Line Drug Treatment

B. H2 Receptor Antagonists (H2RAs) - Second-Line / Add-On

• Less potent than PPIs but still useful for mild symptoms or as add-on for nocturnal acid breakthrough
• Examples: Ranitidine (where available), Famotidine, Cimetidine, Nizatidine
• Famotidine 20 mg twice daily is a common choice
• Can be used at bedtime to suppress nocturnal acid in patients on once-daily PPI who have nocturnal symptoms
• Tolerance (tachyphylaxis) can develop within days-weeks with continuous use

C. Antacids - For Symptomatic Relief

• Provide rapid but short-lived relief (minutes to 1-2 hours)
• Do not heal mucosa
• Used on demand for occasional breakthrough heartburn
• Examples: aluminium hydroxide + magnesium hydroxide (Maalox, Mylanta), calcium carbonate (Tums)
• Alginate-antacid combinations (e.g., Gaviscon) - form a raft on top of gastric contents, mechanically blocking reflux - useful after meals and at bedtime

D. Prokinetics - Adjunctive Role

• Help by increasing LOS pressure and accelerating gastric emptying
• Domperidone or Metoclopramide - limited long-term use due to CNS side effects (metoclopramide causes extrapyramidal effects with prolonged use)
• May be added in patients with documented delayed gastric emptying or regurgitation-predominant symptoms
• Not recommended as monotherapy

E. Sucralfate - Mucosal Protective Agent

• Binds to ulcerated/eroded mucosa and forms a protective barrier
• Limited role in GERD but may be used adjunctively in selected patients with active erosions
• Must be taken on empty stomach, 1 hour before meals - do not take with PPIs (needs acidic environment to activate)

Step 3 - Treatment Algorithm for Mild Erosive OE

Mild Erosive Oesophagitis (LA Grade A/B)
              ↓
   Lifestyle Modifications (ALL patients)
              ↓
   PPI once daily before breakfast
   (4-8 weeks)
              ↓
     ┌─────────────────────────────┐
     │        Healed?              │
     └─────────────────────────────┘
      YES ↓                  NO ↓
   Step down           Double dose PPI
   (lowest dose PPI    OR switch PPI
    or on-demand)      (further 4-8 wks)
              ↓
   Monitor - check for complications,
   Barrett's if recurrent/chronic

Step 4 - Maintenance Therapy

• After confirmed healing, attempt step-down to lowest effective PPI dose
• Consider on-demand PPI (taken only when symptoms occur) - suitable for many Grade A/B patients
• Long-term continuous PPIs are generally not required for mild disease unless symptoms relapse frequently

Step 5 - When to Consider Surgery

• Patient is intolerant of or non-compliant with long-term medical therapy
• Young patient who does not wish to take lifelong medication
• Documented abnormal acid exposure on pH monitoring despite adequate PPI therapy
• Predictors of good surgical outcome: typical symptoms (heartburn/regurgitation), good response to PPI, abnormal 24-hour pH study

Alarm Symptoms - Escalate Immediately If Present

• Dysphagia (difficulty swallowing)
• Odynophagia (painful swallowing)
• Haematemesis or black/tarry stools
• Unexplained weight loss
• Iron deficiency anaemia
• Choking / chronic cough
• Hoarseness

Summary Table

Sources: Textbook of Family Medicine 9th Ed (Table 38-7 Lifestyle Modifications; Fig 38-8 Treatment Algorithm); Yamada's Textbook of Gastroenterology 7th Ed; Harrison's Principles of Internal Medicine 22E; Sleisenger and Fordtran's Gastrointestinal and Liver Disease; Clinical Gastrointestinal Endoscopy 3rd Ed