Azithromycin

Antibiotic — Macrolide

Nigerian brand names:ZithromaxAzithrocinAzimaxAzimacZentavion

Reviewed by the PMC Medical Team · Promise Medical Centre

Overview

Azithromycin is a broad-spectrum macrolide antibiotic used to treat a variety of bacterial infections. It is particularly valued for its convenient once-daily dosing and short treatment courses (often 3–5 days) compared to other antibiotics. Azithromycin concentrates in tissue and has a long half-life, meaning effective drug levels are maintained for several days after the last dose. It is effective against a range of respiratory pathogens, sexually transmitted infections, and certain atypical bacteria. In Nigeria, it is widely used for respiratory tract infections, sexually transmitted infections, and as part of trachoma control programmes.

Uses

• Community-acquired pneumonia (mild-to-moderate) and respiratory tract infections • Acute exacerbations of chronic bronchitis • Pharyngitis and tonsillitis (when penicillin cannot be used) • Sinusitis • Sexually transmitted infections — chlamydia (first-line), gonorrhoea (in combination), chancroid • Skin and soft tissue infections (mild) • Trachoma — eye infections; mass drug administration programmes use azithromycin annually • Traveller's diarrhoea (especially in areas with fluoroquinolone resistance) • Prevention of disseminated Mycobacterium avium complex (MAC) in AIDS patients • Whooping cough (pertussis) — first-line treatment

How to Use

Standard adult dosing: • Respiratory tract infections: 500 mg on Day 1, then 250 mg once daily on Days 2–5 (5-day course) • Chlamydia: 1 g as a single dose • Community-acquired pneumonia: 500 mg once daily for 3 days • Skin infections: 500 mg on Day 1, then 250 mg daily for 4 more days Children: • Weight-based dosing — consult doctor or follow package instructions carefully • Suspension available for children Take on an empty stomach or with food — food improves tolerability Complete the full prescribed course — the drug continues to work for several days after the last dose Note: taking the 3-day or 5-day course is as effective as longer courses of other antibiotics for most indications due to azithromycin's tissue-concentrating properties.

Side Effects

Common: • Nausea • Diarrhoea • Abdominal pain and stomach cramps • Vomiting • Headache Less common: • Loss of appetite • Dizziness • Skin rash • Elevated liver enzymes (usually reversible) Important side effects: • QT interval prolongation — azithromycin can cause a change in heart rhythm; more dangerous in people with pre-existing heart conditions, low potassium/magnesium, or taking other QT-prolonging drugs. Symptoms: palpitations, dizziness, fainting • Hearing loss — rare; occurs mainly with high doses or prolonged treatment; usually reversible • Clostridioides difficile diarrhoea — severe, persistent, or bloody diarrhoea • Severe allergic reactions (rare)

Warnings & Precautions

• Heart conditions: use with caution in patients with known QT prolongation, low potassium or magnesium levels, bradycardia, or those taking other QT-prolonging medications • Liver disease: caution in significant hepatic impairment — drug is metabolised in the liver • Myasthenia gravis: azithromycin may worsen muscle weakness — use an alternative antibiotic if possible • Pregnancy: generally considered safe; use only when clearly needed • Breastfeeding: small amounts in breast milk; generally considered acceptable Antibiotic stewardship: • Only use when prescribed for a confirmed bacterial infection • Azithromycin resistance is increasing rapidly, particularly in sexually transmitted pathogens — test and treat with confirmed susceptibility where possible

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Drug Interactions

• Antacids containing aluminium or magnesium: reduce azithromycin absorption — take 1–2 hours apart • Warfarin: may increase anticoagulant effect — monitor INR • Drugs that prolong the QT interval (amiodarone, haloperidol, methadone, certain antimalarials, antifungals): additive cardiac risk — avoid if possible • Ergotamine: increased risk of ergotism • Digoxin: azithromycin may increase digoxin levels — monitor for toxicity • Cyclosporine: azithromycin can increase cyclosporine levels

Storage

• Store at room temperature (below 30°C) away from moisture and sunlight • Azithromycin suspension: after reconstitution, use within 5 days; do not refrigerate the suspension unless stated on the label • Keep out of reach of children

Buy only NAFDAC-registered medications

Nigeria has a significant problem with counterfeit and substandard drugs. Always purchase medications from a licensed pharmacy and check the NAFDAC registration number on the package — verify at nafdac.gov.ng.