Photochemotherapy for psoriasis with orally administered methoxsalen

Abstract

Photochemotherapy denotes a therapeutic approach that is based on the interaction of light and a photoactive drug. The efficacy is described of photochemotherapy, using orally administered methoxsalen and long-wave UV light in 91 patients with severe, generalized psoriasis. Oral administration of methoxsalen was followed by exposure to a high-intensity long-wave UV light source, emitting a continuous spectrum between 320 and 390 nm (peak, 365 nm) and an energy of 5.6-7.5 mW/cm2 at 15 cm. There was complete clearing of 82 patients (90%), a 90-100% clearing in 7 (8%) and a satisfactory improvement in 2 (2%). A paired comparison study in 54 patients showed photochemotherapy to be more effective than UV light emitted by fluorescent bulbs or a Xe source. Of the patients receiving outpatient maintenance treatment, 85% have remained in remission for periods up to 400 days.