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 (< 220mg/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.
