Background  Acitretin is available for use in psoriasis since the late 1980s; however, there is no consensus on its optimum effective dose with acceptable side-effects.

Objective  To evaluate the efficacy and safety of acitretin in three fixed doses in adult patients with severe plaque type psoriasis.

Methods  This was a randomized, double blind, parallel group, dose ranging study. The study included patients of either gender (age range, 18–65 years) with severe chronic plaque type psoriasis. Of the 80 patients screened, 61 were randomly assigned to three groups: group A – 20 patients (acitretin 25 mg/day), group B – 20 patients (acitretin 35 mg/day) and group C – 21 patients (acitretin 50 mg/day) for 12 weeks. Forty-eight patients completed the study. The main outcome measure was change in Psoriasis Area Severity Index (PASI) score between the three groups from baseline to 12 weeks.

Results  After 12 weeks of therapy, the percentage reduction in the PASI score was 54%, 76% and 54% in acitretin 25, 35 and 50 mg/day group respectively. PASI 75 was achieved in 47%, 69% and 53% patients in acitretin 25, 35 and 50 mg/day groups respectively. The majority of adverse events were mucocutaneous, mild-to-moderate severity and dose dependent.

Conclusions  Acitretin 35 mg/day was observed to be more efficacious compared to 25 mg/day and 50 mg/day dosing, whereas its safety profile is better than 50 mg/day dosing in the management of severe plaque type psoriasis in adult patients.