Methotrexate and liver function: a study of 13 psoriasis cases treated with different cumulative dosages.

BACKGROUND: The need and frequency of hepatic biopsies during methotrexate (MTX) therapy are still controversial. OBJECTIVES: The purpose of this investigation is to assess MTX liver toxicity in patients with psoriasis through percutaneous liver biopsy, and compare liver morphology changes with increasing cumulative dosages (1, 2, 3 and 4 g) of MTX. RESULTS: Cumulative dosages of 1 to 2 g MTX did not cause significant liver toxicity. From a cumulative dosage of 3 to 4 g, there is fibrosis formation, inflammation enhancement in the portal area and fibrous septa, configuring regenerative nodes. CONCLUSION: In patients with no risk factors for liver disease, with normal physical examination and liver tests, biopsy can be done after a cumulative MTX dosage of approximately 1 to 1.5 g and repeated for each gram. In patients with risk factors, liver biopsy should be done before use of MTX, or within the first 2 months of treatment at the most, and repeated for each gram of cumulative dosage.