Low-dose isotretinoin in the treatment of acne vulgaris.

The efficacy of isotretinoin at 0.5 to 1.0 mg/kg per day in the treatment of acne is well established and considered safe, although it is sometimes not easily tolerated because of its cutaneous side effects. The purpose of this study was to determine the efficacy of low-dose isotretinoin in the treatment of acne. In this prospective, noncomparative, open-label study, 638 patients, both male and female, with moderate acne were enrolled and treated with isotretinoin at 20 mg/d (approximately 0.3-0.4 mg/kg per day) for 6 months. The patients were divided into two age groups: 12 to 20 and 21 to 35 years old. Patients were evaluated at 2-month intervals by means of clinical and laboratory examinations. A 4-year follow-up was also carried out. At the end of the treatment phase, good results were observed in 94.8% of the patients aged 12 to 20 years, and in 92.6% of the patients aged 21 to 35 years. Failure of the treatment occurred in 5.2% and 7.4% of the two groups, respectively. Twenty-one patients dropped out of the study because of lack of compliance, and another patient discontinued participation because of a laboratory side effect. During the 4-year follow-up period, relapses of the acne occurred in 3.9% of the patients aged 12 to 20 years and in 5.9% of the patients aged 21 to 35 years. Elevated serum lipid levels (up to 20% higher than the upper limit of normal value) were found in 4.2% of the patients and abnormal (<twice the upper limit of normal values) liver tests were observed in 4.8%. This was a noncomparative, open-label study. Six months of treatment with low-dose isotretinoin (20 mg/d) was found to be effective in the treatment of moderate acne, with a low incidence of severe side effects and at a lower cost than higher doses.