1. Clinical & Scientific Overview
Azithromycin Dihydrate (TIP-MED-000131, Reference Code [8.3]) is classified under
Antimicrobials — Antibacterial & Antibiotic Agents (Ch 08) as a Azalide Macrolide Antibiotic (Bacteriostatic 50S Ribosomal Subunit Protein Synthesis Inhibitor; WHO 'Watch' Group).
Within the Indian regulatory and compendial framework, it is governed under Schedule H Prescription Drug • NLEM 2022 Core Essential Medicine.
Azee (Cipla), Azithral (Alembic), Zithromax (Pfizer)
Oral Film-Coated Tablets: 250 mg, 500 mg; Oral Suspension: 100 mg/5 mL, 200 mg/5 mL; IV Infusion: 500 mg/vial
3. Mechanism of Action & Pharmacodynamics
Reversibly binds to the 23S rRNA of the bacterial 50S ribosomal subunit near the peptidyltransferase centre and blocks the polypeptide exit tunnel, inhibiting aminoacyl-tRNA translocation and bacterial protein synthesis. Primarily bacteriostatic (bactericidal at high concentrations against S. pyogenes and H. influenzae) with a pronounced post-antibiotic effect.
4. Therapeutic Indications & Evidence-Supported Uses
- Community-acquired atypical pneumonia (Mycoplasma, Chlamydophila, Legionella) and acute bacterial sinusitis/otitis
- Uncomplicated enteric fever (Salmonella Typhi/Paratyphi — oral step-down or outpatient therapy in India)
- Sexually transmitted Chlamydia trachomatis urethritis/cervicitis, scrub typhus (pregnancy alternative), and trachoma
5. Educational Dosage Context, Formulations & Administration
Educational Dosing & Regimen Summary: Adults (Respiratory/Skin): 500 mg orally once daily for 3 days (or 500 mg Day 1, then 250 mg Days 2–5). Enteric Fever (Typhoid): 1000 mg (20 mg/kg) once daily for 5–7 days.
Administration & Meal Timing: Oral (once daily) or IV infusion over at least 60 minutes (never give as IV bolus or IM).
6. Pharmacokinetics, Metabolism & Renal/Hepatic Adjustment
Absorption, distribution, metabolism, and excretion follow class pharmacokinetic profile; verify patient renal/hepatic function.
Contraindicated if previous history of Azithromycin-associated cholestatic hepatitis; use caution in severe cirrhosis.
No dose adjustment required in mild-to-severe renal impairment (use caution if eGFR < 10 mL/min).
Contraindicated if previous history of Azithromycin-associated cholestatic hepatitis; use caution in severe cirrhosis.
7. Contraindications, Precautions & High-Risk Warnings
- History of cholestatic jaundice or hepatic dysfunction with prior macrolide use
- Hypersensitivity to Azithromycin, Erythromycin, or any macrolide/ketolide
Key Clinical Precautions: Contraindicated if previous history of Azithromycin-associated cholestatic hepatitis; use caution in severe cirrhosis.
8. Adverse Effects Profile
- Gastrointestinal cramps, nausea, diarrhoea (motilin receptor agonism — significantly milder than Erythromycin)
- QTc interval prolongation and rare polymorphic ventricular tachycardia (Torsades de Pointes)
- Rare reversible sensorineural hearing loss / tinnitus (with high-dose prolonged courses) or cholestatic hepatitis
- Monitor for severe hypersensitivity, organ toxicity, or dose-limiting adverse events.
9. Major Drug–Drug, Drug–Food & Drug–Herb Interactions
- QT-prolonging drugs (Ondansetron, Fluoroquinolones, Amiodarone, Domperidone, Hydroxychloroquine): additive QTc prolongation and Torsades de Pointes risk
- Aluminium/Magnesium Antacids: reduce peak plasma Cmax by ~24% (separate by 2 hours)
- Digoxin: inhibits intestinal P-gp and gut flora inactivation, raising serum digoxin levels
10. Clinical Monitoring, Patient Counselling & Storage
Clinical & Laboratory Monitoring: Monitor clinical response, baseline renal/hepatic parameters, and relevant serum biomarkers.
Pharmacist Patient Counselling Points:
- Complete the full prescribed 3-day or 5-day course; because Azithromycin stays in tissues for 68 hours, it continues working for several days after the last tablet.
- Separate from antacids containing aluminium or magnesium by at least 2 hours.
- Do not self-medicate for viral colds or sore throats (Watch group antibiotic).
Storage, Stability & Dispensing Safeguards: Store below 30°C.
11. Visual Pharmacology & Mechanism Diagram (svg-v339-01-adme-12-step-journey)
12. Authoritative References, Regulatory Sources & Editorial Disclaimer
Primary Compendial & Guideline Reference: Indian Pharmacopoeia (IP 2026) • NLEM 2022 (MoHFW) • CDSCO Approved Prescribing Information
Official Verification Portals: Indian Pharmacopoeia Commission (IPC) & National Formulary of India (NFI) • Central Drugs Standard Control Organization (CDSCO) • Ministry of Health & Family Welfare — NLEM 2022 • NCBI Bookshelf / StatPearls Pharmacology Reference • DailyMed (US FDA Official Prescribing Reference)
Last Medically & Pharmaceutically Reviewed: 2026-11-10 • Verification Status: VERIFIED_EDUCATIONAL_CONTENT
Educational & Clinical Disclaimer: This reference profile is published solely for pharmacy education, academic study, and professional clinical reference. It does not substitute for patient-specific clinical judgement, qualified specialist oncology/medical supervision, or official CDSCO/IP prescribing information. Never self-medicate with prescription, Schedule H/H1/X, NDPS, or oncology medicines.