Description: Azithromycin is a semi-synthetic macrolide antibiotic of the azalide class. dose: Adult: PO- Respiratory tract, Skin and soft tissue infections- 500 mg once daily for 3 days. Or 500mg on day 1 followed by 250mg on days 2 to 5. Typhoid- 500 mg once daily for 7 days. Uncomplicated gonorrhoea- 2 g single dose. Granuloma inguinale- Initial: 1 g, then 500 mg/day until all lesions has healed completely. Chancroid/Chlamydial urethritis: 1 g single dose Prophylaxis of disseminated MAC infections 1.2 g once weekly. Treatment or secondary prophylaxis: administered along with other antimycobacterials: 500 mg once daily. Mechanism of action Azithromycin binds to the 50S subunit of the 70S bacterial ribosomes, and therefore inhibits RNA-dependent protein synthesis in bacterial cells. Half life : 68 hours