It is an isomer of tretinoin.

INDICATIONS: Systemic treatment of dodulo-cystic and conglobate acne, severe acne, acne which has not responded to adequate course of systemic antibacterial or acne associated with psychological problems.

DOSAGE: Adults: Initially 500mcg/kg daily (in 1-2 divided doses) with food, for 4 weeks. If good response, continue for further 8-12 week; if little response increase to 1mg/kg daily 8-12 weeks. If intolerant, reduce dose to 100-200 mcg/kg daily. Usually given for 16 weeks, repeat course is not normally required.

Children: Not recommended.

CONTRAINDICATIONS: Renal or hepatic impairment, hypervitaminosis a, hyperlipidaemia.

SPECIAL PRECAUTIONS: Exclude pregnancy. Avoid blood donation during treatment and at least one month after treatment; history of depression. Monitor hepatic function and lipids before treatment, one month after starting treatment and then every three months, diabetes, dry eye syndrome. Avoid keratoytics.

SIDE-EFFECTS: Nausea, headache, malaise, drowsiness, sweating. Benign intracranial hypertension (avoid concomitant use of tetracycline). Myalgia, arthralgia. Dryness of skin, epidermal fragility; rarely acne fulminans, facial hyperpigmentation. Dryness of lips, nasal mucosa, pharyngeal mucosa, conjunctive. Visual disturbances, Hair thinning. Raised serum creatinine, plasma triglycerides, cholesterol.

DRUG INTERACTIONS: Alcohol, antibacterials, warfarin, antieplieptics, cytotoxic drugs, oestrogens and progestogens, vitamins.