Azithromycin is more active than erythromycin against some Gram-negative organisms such as Chlamydia trachomatis. The concentration and persistance of azithromycin is much higher in the tissue than in plasma; a single dose of azithromycin is used in the treatment of uncomplicated genital chlamydia and trachoma. Azithromycin is not recommended if there is a possibility of gonorrhoea because macrolide resistance emerges rapidly when it is used in this setting.
Uses: uncomplicated genital chlamydial infections and trachoma
Contraindications: hepatic impairment (Appendix 5)
Precautions: pregnancy (Appendix 2) and breastfeeding (Appendix 3); prolongation of QT interval (ventricular tachycardia reported); interactions: Appendix 1
Dose: Uncomplicated genital chlamydial infections or trachoma, by mouth, ADULT over 45 kg 1 g as a single dose; under 45 kg 20 mg/kg as a single dose
PATIENT ADVICE. Not to be taken at the same time as aluminium- or magnesium-containing indigestion remedies. Capsules should be taken at least 1 hour before or 2 hours after food; oral suspension can be taken with food
Adverse effects: see under Erythromycin (but fewer gastrointestinal effects); also anorexia, dyspepsia, flatulence, constipation, pancreatitis; syncope, dizziness, headache, drowsiness, agitation, anxiety, hyperactivity; photosensitivity; hepatitis, interstitial nephritis, acute renal failure, asthenia, paraesthesia, arthralgia, convulsions, mild neutropenia, thrombocytopenia, tinnitus, hepatic necrosis, hepatic failure, tongue discoloration, and taste disturbances