Short-term methotrexate administration by low-dose infusion--does it influence clearance of psoriasis?

Twenty-four patients between them received 86 low-dose methotrexate infusions (given over 36 or 48 h) delivered by a Graseby syringe pump in addition to conventional topical therapy during hospital admission for treatment of severe psoriasis (either erythrodermic or severe widespread plaque-type). The average length of hospital stay, usually the time taken to achieve complete clearance, and the average relapse time in the group of patients overall showed no differences from a control group of 25 patients (matched for age and sex) having a similar severity of psoriasis treated without methotrexate. However, separation of the patients into three sub-groups (erythrodermic, severe and 'unstable' widespread plaque-type, and severe and 'stable' widespread plaque-type disease) revealed that erythrodermic patients, as expected, cleared significantly quicker when receiving methotrexate although severe and 'unstable' widespread plaque-type patients had their clearance times possibly prolonged by short-term methotrexate administration. Although methotrexate is commonly used for long-term management of patients with severe psoriasis, short-term methotrexate administered in this manner cannot necessarily be recommended for severe widespread plaque-type disease. Measurement of methotrexate levels in a further 24 patients with severe psoriasis receiving 47 low-dose infusions revealed relatively constant and predictable methotrexate concentrations. Acute side-effects of methotrexate given by the infusion method were minor and uncommon, the infusion being well tolerated by patients. However, the low-dose infusion technique did not, apparently, offer any advantage over conventional methotrexate administration.