Treatment of psoriasis with etretin: a preliminary report

Eight patients with psoriasis (seven with plaque-type and one with palmoplantar pustular psoriasis) were treated with the synthetic retinoid etretin, the active metabolite of etretinate. An initial 8-week double-blind phase of the study with dosages of 0, 25, or 50 mg/day was followed by an open phase in which variable dosages of 25, 50, or 75 mg/day were used to achieve an optimal clinical response. All patients completed a minimum of 6 months of therapy. A good or an excellent response (at least 50% clearing) after 8 months of treatment was noted in six of the eight patients. One patient had a poor response (less than 50% clearing), and one patient continued to have worsening of psoriatic involvement during treatment. The best response occurred in those patients with the most extensive initial plaque involvement or palmoplantar pustulosis. The clinical side effects were similar to those reported with use of etretinate and seemed to be related to the dose. The laboratory abnormalities--primarily mild intermittent elevations of liver enzymes and elevations in serum lipids--were similar to those described in previous reports about etretinate. Both etretin and etretinate are potent teratogens. Because of its shorter half-life, etretin will likely be preferred, especially in female patients of childbearing potential.