Safety and therapeutic effectiveness of 8-methoxypsoralen, 4,5',8-trimethylpsoralen, and psoralen in vitiligo

Abstract

In this paper, we report on 366 East Indian patients with vitiligo who were treated for 2 to 3 years with either 8-methoxypsoralen (8-MOP), 4,5',8-trimethylpsoralen (TMP), or psoralen and sunlight. These patients with amelanotic macules had 10 to 70% skin involvement of 1 to 50 years duration. Male and female patients from ages 12 to 70 years were randomly assigned to 8 treatment groups; the study was conducted on a double-blind protocol. Patients in prone and supine positions were exposed to the sun for 45-60 minutes in gradually increasing doses between 11 a.m. and 2 p.m. thrice weekly and 2 hours after oral ingestion of the drug. The various drug dosage schedules investigated included 9 groups: 0.3 and 0.6 mg 8-MOP/kg; 0.8, 1.8, and 3.6 mg TMP/kg; a combination of 0.3 mg 8-MOP and 0.6 mg TMP/kg; 0.6 and 1.2 mg psoralen/kg, and a placebo. For ethical reasons, the placebo group was terminated after 9 to 12 months of therapy. All patients were photographed before enrollment and at intervals of 6, 12, 18, and 26 months during therapy. Of these patients treated for nearly 2 years, the faces of those 45% receiving the combination dose of 8-MOP plus TMP or low-dose 8-MOP (0.3 mg/kg) were fully repigmented, and nearly 60% achieved 75 to 100% repigmentation of the head and neck. The chest, abdomen, and back were repigmented nearly as well and better than the arms and legs. The patients receiving high-dose schedules of TMP and psoralen achieved better repigmentation response than those on lower dosage but still not as good as patients on 8-MOP or the combination group of 8-MOP plus TMP.(ABSTRACT TRUNCATED AT 250 WORDS)