PHARMACOLOGY AND THERAPEUTICS ETRETINATE THERAPY FOR PSORIASIS AND OTHER KE RATINIZING DISORDERS: A 10-YEAR RETROSPECTIVE STUDY IN SINGAPORE

Background. Etretinate, a second generation retinoic acid, has been reported to be useful in the treatment of psoriasis and other keratinizing disorders. The effectiveness of etretinate for these disorders are studied in a 10-year retrospective study of all patients treated with etretinate in a skin clinic in Singapore. Methods. The case records of 190 cases of psoriasis and other keratinizing disorders treated with etretinate were analyzed. Information collected included demographic data, dosage of etretinate taken, response and side effects, clinical follow-up, and relapse. Results. Most of the cases (72.6%) had psoriasis (138/190). The others had different keratinizing disorders. The dose of etretinate used was 0.15 to 1 mg/kg/day (median 0.36 mg/kg/day), and the duration of the treatment varied from 1 to 120 months (median 6 months). Etretinate was coadministered with UVB (ReuvB) or PUVA (RepuvA) in 89 (46.8%) patients. In psoriasis, the response to treatment was excellent in 41.3% (57/138), good in 36.2% (50/138), fair in 15.9% (22/138), and poor in 6.5% (9/138) of the cases. Patients with plaque-type psoriasis did better with combination therapy than with monotherapy. Those with keratinizing disorders showed excellent, good, fair, and poor responses in 32.7% (17/52), 32.7% (17/52), 25.0% (13/52), and 9.6% (5/52) respectively. Adverse effects were noted in 102 (53.7%) cases and were generally mild and tolerable. Etretinate was discontinued in 24 (12.6%) patients due to significant toxicity. Conclusions. Etretinate is effective for treating psoriasis and other keratinizing disorders. Combination therapy is preferred in chronic plaque psoriasis. Adverse effects are common, but mild and tolerable.