Which statement about low daily dose versus high daily dose isotretinoin is true?

• A. High daily dose has superior long-term efficacy
• B. They have equal long-term efficacy, low dose has fewer side effects, low dose may take longer to reach same outcome
• C. Low daily dose is less effective overall
• D. High daily dose cures acne faster with more side effects

Answer: (B)

Isotretinoin works best in terms of long-term success when the total amount given over the course is similar, not just the daily dose. When you reach a comparable cumulative dose (roughly 120–150 mg/kg in total), the long-term acne clearance tends to be similar whether you give a high daily dose or a low daily dose. The advantage of a lower daily dose is a milder side-effect profile—fewer and less severe mucocutaneous symptoms, lipid elevations, and liver enzyme changes—because peak drug exposure is lower. However, reaching the same level of improvement can take longer with the lower daily dose, since the pace of response is slower.