TREATMENT OF PSORIASIS WITH A NEW MICRONIZED 5-METHOXYPSORALEN TABLETAND UVA RADIATION

Since 1974, phototherapy with psoralen and ultraviolet A (UVA) has bee n used successfully for the treatment of psoriasis. However, undesirab le side effects, including phototoxicity, nausea, stomach pain and hea daches, have led investigators to develop new psoralen compounds. 5-Me thoxypsoralen (5-MOP) has thus been introduced as an alternative to 8- MOP because of its less pronounced side effects. Since the absorption kinetics and bioactivity of 5-MOP are known to be variable, a new micr onized tablet form (5-MOPm) has been developed. In an open randomized study, oral treatments with 5-MOP or 5-MOPm plus UVA radiation were co mpared in 22 psoriatic patients. Skin type and initial psoriasis area severity index did not differ significantly between treatment groups. Serum concentrations were significantly higher (320 vs 85.82 ng/ml) an d occurred earlier (51.8 vs 229.09 min) with 5-MOPm. In addition, a re duction in PASI of more than 90% was achieved sooner (10.63 vs 17.27 t reatments) and with a lower cumulative UVA dose (145.89 vs 232.11 J/cm 2), in the group treated with 5-MOPm. No side effects were observed wi th 5-MOPm. Our data indicate that 5-MOPm has a higher bioavailibility, clinical efficacy and tolerability than the commonly used 5-MOP.