Drug Breakdown: Isotretinoin

Day 1: A synthetic vitamin A derivative, #isotretinoin was discovered in the 1950s & originally used for skin cancer. Its effect on the cell cycle led to the discovery of efficacy for severe acne management, which is now the only licensed use in UK; Also known as brand names e.g #Roaccutane

Day 2: If severe acne is resistant to 1st line treatment, #isotretinoin is licensed for those over 12 yrs & is initiated by specialist. Typical range 0.5-1mg/kg/day for up to 24 weeks. The course can be repeated after 8 weeks; interval to allow time for further improvement post-cessation. #isotretinoin can produce long-term remission from severe acne

Day 3: #isotretinoin is an oral systemic retinoid with low bioavailability & high lipophilicity & Vd. Metabolism is by isomerisation, CYP450 & enterohepatic recycling. There are active metabolites. Renal/faecal elimination, t½ 25hrs. Avoid in hepatic impairment & severe renal impairment. Monitor lipids & LFTs before/during

Day 4: Exact mechanism of action for #isotretinoin is unclear, but known to reduce sebaceous gland size & inhibit sebum release & reduce clogged pores. Also inhibits cell proliferation & reduces inflammation