Importance: Isotretinoin is the most effective treatment for acne. The ideal dosing regimen is unknown.
Objective: To determine the rates of relapse of acne vulgaris and retrial of isotretinoin after high cumulative-dose treatment and the changes to the adverse effect profile.
Design, setting, and participants: A prospective, observational, intervention study was conducted from August 1, 2008, to August 31, 2010, in a single academic tertiary care center with multiple providers. A total of 180 patients with acne resistant to other treatments were enrolled. Of these, 116 participated in the 12-month follow-up survey, for a response rate of 64.4%.
Exposure: Patients received isotretinoin, with dosing based on the providers' judgment. Patients were divided into 2 groups on the basis of cumulative dosing (<220 mg/kg and ≥ 220 mg/kg).
Main outcomes and measures: Relapse (treatment with a prescription topical or oral acne medication after a course of isotretinoin) or retrial (retreatment with isotretinoin) at 12-month follow-up and adverse effects experienced during and after 12 months of treatment. RESULTS The mean age of the participants was 19.3 years, 51.9% were female, and 74.1% were white. At 12 months' follow-up, 97.4% of the patients reported that their acne was improved. Overall, acne in 32.7% of patients in the study relapsed at 12 months, and 1.72% of the patients required a retrial. In the lower-dose treatment group (<220 mg/kg), the relapse rate was 47.4% (95% CI, 32.3%-63.0%) compared with 26.9% (95% CI, 18.3%-37.8%) in the high-dose group (P = .03). Almost 100% of the patients in both treatment groups developed cheilitis and xerosis during treatment. Retinoid dermatitis was significantly more common in the high-dose treatment group (53.8% vs 31.6%; P = .02). None of the other adverse effects was significantly different between the 2 groups.
Conclusions and relevance: The dosing regimen used in the present study is considerably higher than that used in previous studies of isotretinoin. At 1 year after completion of isotretinoin treatment, we found that patients receiving 220 mg/kg or more had a significantly decreased risk of relapse. Rash was the only adverse effect that was significantly more common in the high-dose group during treatment. This study suggests that significantly higher doses of isotretinoin are effective for treating acne and decreasing relapse rates without increasing adverse effects.