• Methotrexate sodium is a well-established therapeutic agent for severe psoriasis, but its use may be associated with hepatic fibrosis. We studied the pharmacokinetics of oral and intramuscular methotrexate in two groups of patients—those who did and those who did not develop hepatic fibrosis while receiving methotrexate therapy. Our results showed no difference between the two groups for peak or 24-hour methotrexate concentrations; for area under the curve to 24, 144, and 24 to 144 hours; or in total-body methotrexate clearance. Measurement of methotrexate plasma levels after drug administration is therefore unlikely to help in identifying those patients at risk of developing fibrosis.
(Arch Dermatol 1986;122:666-669)