METHOTREXATE FOR PSORIASIS

Methotrexate is an effective antipsoriatic agent and has been widely u sed to treat severe psoriasis since the 1960s. It is especially useful in acute generalized pustular psoriasis, psoriatic erythroderma psori atic arthritis and for extensive chronic plaque psoriasis in patients who are inadequately controlled by topical therapy alone. It has not, however, been formally compared with other systemic treatments for sev ere psoriasis such as cyclosporin, retinoids or photochemotherapy with psoralen and UVA (PUVA), but in comparison with correct with these ot her therapies it is inexpensive, use, its safety profile is favourable . In summary therefore, it can be used as a short-term option to gain control of unstable psoriasis such as pustular psoriasis or erythroder ma before returning to other modes of treatment, or more often, as lon g-term maintenance treatment. The most important potential side-effect is acute myelosuppression, which is the cause of most of the rare dea ths attributable to this therapy for psoriasis. Myelosuppression is mo re likely in the elderly, in patients with renal impairment and/or fol ate depletion, and with overdose or drug interactions. Long-term thera py carries with it a risk of liver fibrosis which is related to the do sage regimen employed, and is increased by exposure to other hepatic t oxins, particularly alcohol. The correlation between the risk of devel opment of liver fibrosis, cumulative lifetime dose and duration of tre atment with methotrexate is not clear-cut, but may have been overstate d in some studies.