Indications: acne vulgaris, rosacea, exacerbations of chronic bronchitis; infections due to brucella, chlamydia, mycoplasma and rickettsia.

Cautions: breast-feeding; rarely causes photosensitivity. Avoid administration in hepatic impairment.

Contra-indications: renal failure, pregnancy, children under 12 years of age.

Side Effects: nausea, vomiting, diarrhoea; super- infection with resistant organisms; rarely allergic reactions.

Dose: 250 mg every 6 hours, increased in severe infections to 500 mg every 6–8 hours.

For acne, 250 mg 3 times daily for 1-4 weeks and then reduced to twice daily until improvement occurs.

Non-gonococcal urethritis, 500 mg every 6 hours for 7– 14 days (21 days if failure or relapse after first course)

Pregnancy: First trimester: Effects on skeletal development in animal studies. Second and third trimester: Dental discoloration; maternal hepatotoxicity with large parenteral doses.