Azithromycin Dihydrate
Azalide Macrolide Antibiotic (Bacteriostatic 50S Ribosomal Subunit Protein Synthesis Inhibitor; WHO 'Watch' Group) • Schedule H Prescription Drug • NLEM 2022 Core Essential Medicine
Level 1 — Quick Professional Summary (At a Glance)
Azithromycin Dihydrate
Monograph Code: [8.3] | Stable ID: TIP-MED-000131
Azee (Cipla), Azithral (Alembic), Zithromax (Pfizer)
Azalide Macrolide Antibiotic (Bacteriostatic 50S Ribosomal Subunit Protein Synthesis Inhibitor; WHO 'Watch' Group)
Antimicrobials — Antibacterial & Antibiotic Agents (Ch 08)
Oral Film-Coated Tablets: 250 mg, 500 mg; Oral Suspension: 100 mg/5 mL, 200 mg/5 mL; IV Infusion: 500 mg/vial
Route: Oral / Parenteral / Topical as specified by formulation
9–10. 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.
12. Therapeutic Indications
- 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
13 & 16. Contraindications, Precautions & Warnings
- History of cholestatic jaundice or hepatic dysfunction with prior macrolide use
- Hypersensitivity to Azithromycin, Erythromycin, or any macrolide/ketolide
Contraindicated if previous history of Azithromycin-associated cholestatic hepatitis; use caution in severe cirrhosis.
14. Dosage & Administration Context (Educational Reference Summary)
Administration & Timing: Oral (once daily) or IV infusion over at least 60 minutes (never give as IV bolus or IM).
Level 2 — Detailed Pharmacology, PK, Interactions & Special Populations
11 & 19. Pharmacokinetics (ADME), Renal & Hepatic Considerations
Pharmacokinetic Profile: Absorption, distribution, metabolism, and excretion follow class pharmacokinetic profile; verify patient renal/hepatic function.
Renal Considerations: No dose adjustment required in mild-to-severe renal impairment (use caution if eGFR < 10 mL/min).
Hepatic Considerations: Contraindicated if previous history of Azithromycin-associated cholestatic hepatitis; use caution in severe cirrhosis.
15 & 17. Adverse Effects & Clinically Significant Drug Interactions
- 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
- 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
18, 20, 21 & 22. Special Populations, Monitoring, Counselling & Storage
Pregnancy, Lactation, Paediatric & Geriatric Use: Evaluate maternal-foetal benefit-risk ratio and age-appropriate organ function before prescribing.
Clinical & Laboratory Monitoring: Monitor clinical response, baseline renal/hepatic parameters, and relevant serum biomarkers.
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 & Dispensing Governance: Store below 30°C.
Visual Pharmacology Mechanism Diagram (PLATE-8.9)
23. Traceable Source References & Jurisdiction
Primary Reference Record: Indian Pharmacopoeia (IP 2026) • NLEM 2022 (MoHFW) • CDSCO Approved Prescribing Information
Authoritative Verification Portals: Indian Pharmacopoeia Commission (IPC) • CDSCO (India Jurisdiction) • NCBI Bookshelf • DailyMed (US FDA Label Reference)
Last Checked Date: 2026-11-08 • Related Study Guide: Antimicrobial Stewardship & PK/PD Optimization →