Effects of oral methoxy-psoralen photochemotherapy (PUVA) on liver function and antipyrin kinetics

Standard liver function tests and antipyrin kinetics were studied in 19 non-alcoholic patients before and after a four-week PUVA treatment with oral methoxy-psoralen. Whereas liver function remained normal in all subjects, antipyrin clearance was significantly reduced at the end of PUVA therapy. Although the mechanism of this pharmacological effect remains unclarified, these results suggest that there is considerable potential for interactions to occur with other drugs metabolized by the same hepatic pathways (cytochrome P 450) in patients undergoing PUVA therapy.