Methotrexate is potentially toxic and so patients must be carefully monitored. Methotrexate should only be used by clinicians who are familiar with the various characteristics of the drug and its mode of action.
Pre-treatment check or before reinstituting methotrexate after a rest period (1): For example pretreatment:
- chest X-ray (1)
- FBC U+E Creatinine LFT GGT
- do not give Methotrexate if renal impairment or abnormal liver tests
For the first two months:
- fortnightly FBC LFT and GGT
- thereafter monthly If raised MCV, check serum folic acid.
Notes:
- patients should be subject to appropriate supervision every 2-3 months so that signs of possible toxic effects or adverse reactions may be detected and evaluated with minimal delay. Renal function and blood counts should be closely monitored before, during and after treatment.
- patients should be advised to report all signs and symptoms suggestive of infection
- malignant lymphomas may occur in patients receiving low dose methotrexate, in which case therapy should be discontinued. Failure of the lymphoma to show signs of spontaneous regression requires the initiation of cytotoxic therapy
- methotrexate given concomitantly with radiotherapy may increase the risk of soft tissue necrosis and osteonecrosis
- patients should be advised of the risk of pneumonitis and advised to seek medical attention if symptoms (dyspnoea, dry non-productive cough and fever) develop. If methotrexate-induced pneumonitis is suspected then methotrexate is withdrawn and corticosteroids administered (2)
Reference:
- Wyeth (February 2001). Methotrexate injection 25mg/ml and methotrexate 2.5mg tablets. New Summary of Product Characteristics and Data Sheet.
- CMO's Update 35 (January 2003), 6.