Pancytopenia associated with low dose methotrexate therapy. A regional survey.
OBJECTIVE
To determine which risk factors are associated with serious pancytopenia associated with low dose methotrexate (MTX) therapy.


METHODS
All Ottawa area rheumatologists, hematologists and dermatologists were surveyed to obtain cases of pancytopenia associated with low dose MTX therapy between 1981 and 1991. Pancytopenia was defined as white blood cells < 3.5 x 10(9)/l and platelets < 140 x 10(9)/l and hemoglobin < 100 g/l. A case control method was used to evaluate risk factors.


RESULTS
Fifteen cases of pancytopenia were identified from returned questionnaires (93% response rate) and from reviewing the medical records of 2 major teaching hospitals. All patients were hospitalized, had MTX therapy discontinued and were treated: 12 patients received transfusions, 8 leucovorin therapy, and 4 folic acid. Two patients died, only 1 directly due to MTX therapy. Identified risk factors were (1) elevated BUN or creatinine levels, (2) increasing mean corpuscular volume values, (3) increased age and (4) concomitant trimethoprim-sulfamethoxazole therapy.


CONCLUSIONS
Pancytopenia associated with low dose MTX therapy is a life threatening adverse effect often associated with known risk factors. A change in monitoring guidelines and patient education are suggested as means of risk reduction.
al-Awadhi
A
A
Rheumatic Disease Unit, Ottawa General Hospital, University of Ottawa, ON, Canada.
Dale
P
P
McKendry
R J
RJ
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015535:Arthritis, Psoriatic / Q000188:drug therapy; D001172:Arthritis, Rheumatoid / Q000188:drug therapy; D001806:Blood Urea Nitrogen; D002170:Canada; D003404:Creatinine / Q000097:blood; D004305:Dose-Response Relationship, Drug; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use; D006306:Health Surveys; D006801:Humans; D002955:Leucovorin / Q000627:therapeutic use; D008297:Male; D008727:Methotrexate / Q000009:adverse effects* / Q000627:therapeutic use; D008875:Middle Aged; D010198:Pancytopenia / Q000139:chemically induced* / Q000453:epidemiology / Q000378:metabolism; D011565:Psoriasis / Q000188:drug therapy; D012307:Risk Factors; D011795:Surveys and Questionnaires; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000627:therapeutic use
D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D005492:Folic Acid; D003404:Creatinine; D002955:Leucovorin; D008727:Methotrexate