Methotrexate hepatotoxicity in psoriasis--comparison of different dose regimens.

Liver histological appearances were studied in 44 patients treated for psoriasis with methotrexate. Cirrhosis was found in six and hepatic fibrosis in another 11. Of these 17 patients 12 had received methotrexate by a regimen of frequent small dosage, two had been treated by a regimen of intermittent large dosage, while three had been treated at different times by both methods. The prevalence of cirrhosis and fibrosis was significantly greater in patients treated by frequent small dosage than in those treated by intermittent large dosage, though the dose level (mg/month) was similar in both groups. Hepatic fibrosis, sometimes preceding cirrhosis, seems to develop invariably if treatment with small frequent dosage is sufficiently prolonged. In the few circumstances in which this drug is indicated for psoriasis intermittent large dosage is the treatment regimen of choice.