Low dose methotrexate and bone marrow suppressionBMJ 2003; 326 doi: https://doi.org/10.1136/bmj.326.7383.266 (Published 01 February 2003) Cite this as: BMJ 2003;326:266
- Michael Sosin, senior house officer,
- Sunil Handa (email@example.com), consultant haematologist
- Department of Haematology, Sandwell General Hospital, West Bromwich, West Midlands, B71 4HJ
- Correspondence to: Sunil Handa
- Accepted 28 June 2002
Bone marrow suppression can occur even with low doses of methotrexate
Methotrexate is an antimetabolite that, apart from its use in malignant disorders, is taken orally in low doses for the control of conditions such as rheumatoid arthritis and psoriasis. When used in chemotherapy it causes profound suppression of bone marrow. However, even at a low dose it may be associated with bone marrow suppression—particularly in the presence of renal insufficiency or when other drugs are taken concomitantly (box 1). Its unusual weekly dosing regimen can result in dose error by patients or clinicians. We present three cases of bone marrow suppression in patients taking low dose methotrexate who presented at a district general hospital during a period of four years (table).
A 78 year old woman with rheumatoid arthritis had been taking a weekly dose of 17.5 mg of methotrexate for two months. Before this the dose had been gradually built up over several years. She was admitted with breathlessness and found to be pancytopenic (haemoglobin concentration 100 g/l, white cell count 3.0 × 109/l, neutrophils 2.5 × 109/l, platelets 13 × 109/l). A month earlier her full blood count had been normal.
Methotrexate treatment was discontinued. She was treated with intravenous folinic acid and antibiotics and was given transfusions of blood products. Her blood count showed recovery (haemoglobin concentration 137 g/l, white …