Photochemotherapy in psoriasis-clinical response and 8-MOP plasma concentrations at two dose levels

Clinical response and 8-MOP plasma concentrations at two dose levels (10 and 40 mg 8-MOP) using an improved tablet formulation were studied in fifty-six psoriatic patients taking part in a two–centre PUVA trial. Clinical improvement was observed in all patients receiving 40 mg 8–MOP. To achieve a comparable clinical result, it was necessary to increase the dose of 8–MOP to 40 mg in twenty–six of the thirty patients initially treated with 10 mg 8–MOP. The great inter–subject variation previously reported in 8–MOP plasma levels and clinical effect was confirmed. Although in most cases high 8–MOP plasma levels were associated with high doses of 8–MOP and satisfactory clinical results, 8–MOP plasma concentration does not seem a reliable parameter for the prediction of treatment results or for optimizing PUVA treatment.