Is less more with isotretinoin and acne?

Evidence • Three RCTs compared conventional with low dosing. -For 24 weeks, 60 patients with moderate acne used low (0.25 to 0.4 mg/kg daily) or conventional doses (0.5 to 0.7 mg/kg daily).1 The low-dose group showed equivalent efficacy (acne grading and lesion counts); increased patient satisfaction (76% very satisfied vs 31%); and a higher (non-significant) 1-year relapse rate (18% vs 13%). -For 20 weeks, 150 patients with treatment-resistant nodulocystic acne used 0.1, 0.5, or 1 mg/kg daily.2 There was equivalent improvement with all doses; 18-month relapse rates were 42%, 20%, and 10%, respectively. -Lower doses reduced common side effects (chapped lips, dry skin, and epistaxis) by 16% to 35%.1,2 -In 120 patients with mild to severe acne using high (1 mg/kg daily) or low (20 mg/d) doses on alternating days for 16 weeks,3 the low-dose group had a decrease in acne load (81% vs 95%) and fewer side effects. • A large prospective study (638 patients with moderate acne; 20 mg/d for 24 weeks) reported “good results” in about 94% of patients, decreased incidence of side effects, and a 5% relapse rate at 4 years.4 • Smaller observational studies (doses about 20 mg/d) support these findings5-7; 2 studies report improved outcomes with a total cumulative dose of 120 mg/kg.5,7