PANCYTOPENIA AND SEVERE CYTOPENIA INDUCED BY LOW-DOSE METHOTREXATE - 8 CASE-REPORTS AND A REVIEW OF 100 CASES FROM THE LITERATURE (WITH 24 DEATHS)

Severe adverse effects of low-dose methotrexate (less than 20 mg per w eek) are believed to be rare, We report eight cases of severe tricytop enia or pancytopenia seen in two medical departments of the same hospi tal in patients receiving low-dose methotrexate. Three patients had be en under methotrexate for less than one month, Of the six patients wit h joint disease, five had rheumatoid arthritis and one psoriatic arthr itis, A review of the literature found 92 previously reported cases of severe tricytopenia or pancytopenia induced by low-dose methotrexate, Of the total of 100 cases, 24 were fatal and 25 occurred within one m onth of treatment initiation, Potential risk factors were identifiable retrospectively in at least 50% of cases but were not all predictable or present at treatment initiation, In 30% of cases, no explanation f or the hematologic complication was found, and in an additional 20% mi ssing data precluded definite conclusions, The role of the risk factor s incriminated in the literature is discussed, Although infrequent, cy topenia is a severe complication of methotrexate therapy that warrants a number of precautions, including periodic creatinine clearance and serum albumin determinations, Furthermore, the weekly dosing schedule should be printed on methotrexate boxes.