Case 1: Patient P. 56 years old complains about heartburn, more at night and in the morning; burning sensation behind the sternum, appearing immediately after eating; nausea, sore throat, burp with a sour taste. EDS revealed inflammatory changes in the distal esophagus characteristic of the non-erosive form of gastroesophageal reflux disease. 1. Identify the problem (diagnosis) and mark your R-medication for this condition 2. R-medicine: 3. Dosage form 4. Pharmacokinetics of the drug 5. Mechanism of action 6. Dosage 7. Write a prescription 8. Duration of treatment 9. Side effects 10. Contraindications Short answers please

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Based on the retrieved sources and my pharmacology knowledge, here is a concise clinical summary:

Case 1 — GERD (Non-Erosive Form)

1. Diagnosis

Gastroesophageal Reflux Disease (GERD), non-erosive form (NERD) Confirmed by EDS showing distal esophageal inflammation without mucosal erosions. Classic symptoms: heartburn (worse at night/morning), retrosternal burning post-meal, nausea, sore throat, acid regurgitation.

2. R-Medication

Omeprazole (Proton Pump Inhibitor — PPI; first-line for GERD)

3. Dosage Form

Enteric-coated capsules (delayed-release) 20 mg or 40 mg; also available as tablets.

4. Pharmacokinetics

Parameter	Details
Absorption	Oral; enteric coating protects against gastric acid; peak plasma in ~1–3 h
Bioavailability	~35–60% (first-pass hepatic metabolism); increases with repeated dosing
Protein binding	~95%
Metabolism	Hepatic via CYP2C19 and CYP3A4
Half-life	~0.5–1 hour (but antisecretory effect lasts 24 h due to irreversible binding)
Excretion	Urine (~77%), feces (~18%)

5. Mechanism of Action

Omeprazole is a prodrug — activated in the acidic canaliculi of parietal cells → forms a sulfenamide that irreversibly inhibits H⁺/K⁺-ATPase (proton pump), the final step of gastric acid secretion. Reduces basal and stimulated acid output by up to 80–90%. New pumps must be synthesized for acid secretion to resume (~18–24 h).

6. Dosage

NERD/GERD: Omeprazole 20 mg once daily, taken 30 minutes before breakfast
Severe/refractory cases: 40 mg/day

7. Prescription

Rp:
  Omeprazole 20 mg caps. gastro-resist. №28
D.S.: 1 capsule (20 mg) orally once daily,
      30 minutes before breakfast.

8. Duration of Treatment

Acute symptom relief: 4–8 weeks
NERD typically responds within 2–4 weeks
Maintenance (if relapse): long-term low-dose PPI, on-demand therapy, or step-down to H₂-blocker

9. Side Effects

Frequency	Effect
Common	Headache, diarrhea, nausea, flatulence, abdominal pain
Long-term use	Hypomagnesemia, vitamin B₁₂ deficiency, iron malabsorption, hypergastrinemia, increased risk of C. difficile infection
Rare	Interstitial nephritis, bone fracture (osteoporosis with prolonged use)

10. Contraindications

Hypersensitivity to omeprazole or any PPI (benzimidazole derivatives)
Concurrent use with rilpivirine or atazanavir (requires gastric acidity for absorption)
Caution in severe hepatic impairment (dose reduction needed)
Pregnancy: use only if clearly indicated (Category C)

Sources: Goodman & Gilman's Pharmacological Basis of Therapeutics; Goldman-Cecil Medicine; Sleisenger & Fordtran's Gastrointestinal and Liver Disease; Schwartz's Principles of Surgery.

Mechanism and spectrum of action, side effects, contraindications and indications for prescribing macrolides. Interaction 2. Mechanism and spectrum of action, side effects, contraindications and indications for prescribing leukotriene receptor antagonists. Interaction. Everything according to my pharmacology and the prescription of drug in it

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I now have comprehensive information from Katzung's Basic and Clinical Pharmacology and Jawetz Medical Microbiology. Let me compile both answers:

1. MACROLIDES

(Katzung's Basic & Clinical Pharmacology, 16e; Jawetz Medical Microbiology, 28e)

Mechanism of Action

Macrolides inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit (23S rRNA). This blocks the polypeptide exit tunnel, preventing peptide chain elongation (transpeptidation), causing dissociation of peptidyl-tRNA from the ribosome. The action is generally bacteriostatic (bactericidal at higher concentrations). Activity is enhanced at alkaline pH.

Spectrum of Action

Organism Group	Examples
Gram-positive	Streptococci, pneumococci, staphylococci, corynebacteria, Listeria
Gram-negative	Neisseria, Bordetella pertussis, Campylobacter, H. influenzae (reduced)
Atypicals	Mycoplasma pneumoniae, Chlamydia trachomatis/pneumoniae, Legionella pneumophila
Others	H. pylori, Treponema pallidum, Rickettsia, Mycobacterium avium complex

Azithromycin — enhanced vs. H. influenzae, M. pneumoniae, N. gonorrhoeae, M. catarrhalis Clarithromycin — enhanced vs. H. pylori, Mycobacterium avium, Borrelia burgdorferi

Indications

Community-acquired pneumonia (CAP)
Whooping cough (B. pertussis)
Chlamydial and mycoplasmal infections
Corynebacterial infections (diphtheria)
H. pylori eradication (clarithromycin triple therapy)
Legionella (Legionnaires' disease)
Skin and soft-tissue infections (mild)
STIs (C. trachomatis, N. gonorrhoeae)
MAC prophylaxis/treatment in HIV

Contraindications

Hypersensitivity to macrolides
Hepatic impairment (especially with erythromycin estolate — cholestatic hepatitis)
Pre-existing QT prolongation or concurrent QT-prolonging drugs
Pregnancy: erythromycin estolate contraindicated (hepatotoxicity increased)

Side Effects

System	Effect
GI (most common)	Nausea, vomiting, diarrhea, abdominal cramps (especially erythromycin)
Hepatic	Cholestatic hepatitis (erythromycin estolate), hepatotoxicity
Cardiac	QT prolongation → risk of ventricular tachycardia / torsades de pointes
Rare	Ototoxicity (high-dose erythromycin), hypersensitivity reactions
Azithromycin/clarithromycin	Significantly lower GI side effects than erythromycin

Drug Interactions

Erythromycin & clarithromycin: strong CYP3A4 inhibitors → increase plasma levels of:
- Warfarin (↑ anticoagulant effect → bleeding)
- Statins → rhabdomyolysis risk
- Cyclosporine, tacrolimus → nephrotoxicity
- Digoxin → toxicity
- Theophylline → toxicity
- QT-prolonging drugs (antiarrhythmics, antipsychotics) → additive QT risk
Azithromycin: does not inhibit CYP3A4 — fewer pharmacokinetic interactions, but still has some QT risk

Prescriptions (Representative)

Rp: Azithromycin 500 mg tab. №3
D.S.: 1 tab once daily for 3 days (CAP)

Rp: Clarithromycin 500 mg tab. №14
D.S.: 1 tab twice daily for 7–14 days

2. LEUKOTRIENE RECEPTOR ANTAGONISTS (LTRAs)

(Katzung's Basic & Clinical Pharmacology, 16e; Harrison's Principles of Internal Medicine, 22e)

Mechanism of Action

Leukotrienes (LTC₄, LTD₄, LTE₄ — cysteinyl leukotrienes) are inflammatory mediators derived from arachidonic acid via 5-lipoxygenase (5-LOX). They act on CysLT1 receptors in airway smooth muscle and mucosa, causing:

Bronchoconstriction
Increased mucus secretion
Mucosal edema
Eosinophil recruitment

Montelukast (and zafirlukast) are selective, competitive CysLT1 receptor antagonists — they block leukotriene binding, reducing bronchoconstriction, airway inflammation, and mucus production.

Spectrum of Action (Indications)

Asthma: mild persistent (alternative to inhaled corticosteroids [ICS]) or add-on therapy
Exercise-induced bronchospasm (EIB)
Allergic rhinitis (perennial and seasonal) — especially when co-existing with asthma
Children with mild asthma + concurrent allergic rhinitis (montelukast preferred)
Aspirin-exacerbated respiratory disease (aspirin-sensitive asthma)

Contraindications

Hypersensitivity to montelukast or zafirlukast
Not for acute bronchospasm (no role in rescue therapy)
Caution in hepatic impairment (zafirlukast more so)
Neuropsychiatric warning (FDA Black Box): agitation, depression, suicidal ideation — caution in psychiatric history

Side Effects

Type	Effect
Neuropsychiatric (FDA Black Box)	Agitation, anxiety, depression, insomnia, suicidal thoughts/behavior
GI	Nausea, abdominal pain, diarrhea (mild)
Hepatic	Elevated liver enzymes (especially zafirlukast); rare hepatotoxicity
Rare	Churg-Strauss syndrome (eosinophilic vasculitis) — may be unmasked when oral steroids are tapered
Generally	Well tolerated; oral, once daily — high adherence

Drug Interactions

Montelukast: metabolized by CYP3A4 and CYP2C9 → levels decreased by enzyme inducers (rifampicin, phenobarbital, phenytoin)
Zafirlukast: inhibits CYP2C9 → increases warfarin effect (↑ INR — monitor closely)
Both: generally few significant interactions compared to theophylline or corticosteroids

Prescription

Rp: Montelukast 10 mg tab. №30
D.S.: 1 tab (10 mg) orally once daily in the evening
      (adults & children ≥15 years; asthma/allergic rhinitis)

Rp: Montelukast 5 mg chewable tab. №30
D.S.: 1 chewable tab once daily in the evening
      (children 6–14 years)

Sources: Katzung's Basic and Clinical Pharmacology 16e; Jawetz, Melnick & Adelberg's Medical Microbiology 28e; Harrison's Principles of Internal Medicine 22e

Case 13: The patient has sternum pain of a burning nature, for more than 30 minutes, not relieved by taking nitroglycerin. Objectively: the skin is pale. Heart rate 124 per minute. Blood pressure 120/80 mmHg On an ECG is a sinus rhythm interrupted by frequent ventricular extrasystoles of the bigeminia type. Choose a medication to restore your heart rate. Station 1 1. Identify the problem (diagnosis) : 2. Choose your P-medication for this condition: 3. Dosage form 4. Dosage Station 2 5. Pharmacokinetics of the drug 6. Mechanism of action 7. Write a prescription Station 3 8. Duration of treatment 9. Side effects 10. Contraindications These are exam questions give answers carefully and short

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Excellent — I have all the information needed from Braunwald's Heart Disease. Here is the complete exam answer:

Case 13

Station 1

1. Diagnosis: Acute Myocardial Infarction (AMI / STEMI) complicated by ventricular extrasystoles (ventricular premature beats) in bigeminy — a life-threatening arrhythmia requiring urgent antiarrhythmic therapy. (Retrosternal burning pain >30 min, not relieved by nitroglycerin, tachycardia HR 124, pale skin, ventricular bigeminy on ECG)

2. P-Medication: Lidocaine (Lignocaine) — Class IB antiarrhythmic (Na⁺ channel blocker) First-choice IV antiarrhythmic for acute ventricular arrhythmias in the setting of AMI.

3. Dosage Form: Solution for injection — 1% or 2% solution for intravenous administration

4. Dosage:

Loading (bolus): 1–2 mg/kg IV at a rate of 20–50 mg/min
Repeat bolus: up to 2 more boluses of 1 mg/kg at 5-min intervals if needed
Maintenance infusion: 1–4 mg/min IV (to maintain plasma level 1–5 mcg/mL)
Reduce dose by ½–⅓ in heart failure or reduced cardiac output

Station 2

5. Pharmacokinetics:

Parameter	Detail
Route	IV only (oral gives extensive first-pass hepatic metabolism → unreliable levels)
Distribution	Rapid — large volume of distribution, extensive tissue uptake
Protein binding	~70%
Metabolism	Hepatic (depends on hepatic blood flow)
Half-life	1–2 h (normal); >4 h post-MI; >10 h in heart failure/shock
Excretion	Renal (metabolites)

6. Mechanism of Action: Lidocaine blocks fast sodium channels (INa), preferentially in their open and inactivated states (use-dependent block). It:

Suppresses abnormal automaticity and ectopic activity in His-Purkinje fibers and ventricular muscle
Shortens action potential duration and effective refractory period in Purkinje fibers
Converts unidirectional block to bidirectional block (suppresses re-entry)
Has minimal effect on atrial tissue and AV node → selective for ventricular arrhythmias
Does not affect normal sinus node automaticity at therapeutic doses

7. Prescription:

Rp: Sol. Lidocaini 2% — 10 mL (200 mg) amp. №5
D.S.: Bolus: 100 mg (1 mg/kg) IV slowly over 2–3 min,
      then maintenance infusion 2–4 mg/min IV
      (dilute in 0.9% NaCl or 5% dextrose)
      Under continuous ECG monitoring.

Station 3

8. Duration of Treatment:

Acute IV therapy: 24–48 hours (reassess arrhythmia risk after this period)
After stabilization, switch to oral antiarrhythmic if ongoing therapy is needed

9. Side Effects:

System	Effect
CNS (dose-related, most common)	Dizziness, paresthesia, confusion, drowsiness, delirium, seizures, coma
Cardiac	Sinus node depression, His-Purkinje block, bradycardia (rare at therapeutic doses)
Rare	Malignant hyperthermia
Hemodynamic	Minimal at therapeutic doses; hypotension in high doses or severe LV dysfunction

10. Contraindications:

Hypersensitivity to lidocaine or amide-type local anesthetics
Severe sinoatrial, AV, or intraventricular block (without pacemaker)
Stokes-Adams syndrome
Severe hepatic impairment (markedly impaired clearance)
Cardiogenic shock (greatly prolongs half-life)
Supraventricular arrhythmias (ineffective — lidocaine does not affect atrial tissue)
Wolff-Parkinson-White syndrome with accessory pathway conduction

Source: Braunwald's Heart Disease — A Textbook of Cardiovascular Medicine, 12e

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