Methotrexate
Type of Medication: Immunosuppressant
Indications: CF-related arthropathy. Rheumatoid arthritis. Only on instruction of Rheumatologist
Side Effects: Liver impairment, hepatic fibrosis in up to 10% of cases if >5 g used myelosuppression, mucositis, pneumonitis and pulmonary fibrosis, pulmonary oedema, nausea, alopecia, rash, teratogenic, transient gonadal suppression, diarrhoea, stomatitis, GI ulceration, megaloblastic, renal damage, hepatic damage. Diahorrea, toxic megacolon, urticaria, dizziness, drowsiness, malaise, headache, mood changes, precipitation of diabeties, renal faliure.
Route of administration: Adult (Oral)
Dose:5mg and increase up to 20mg if tolerated. Take as a once a week dose
Administration: Take folic acid to reduce side effects. Either take 5mg every day except on day methotrexate is taken or 10mg 24 hours after methotrexate dose. Use under Rheumatologist supervision only
Examples of some Drug Interactions
Interacting drug: Ciclosporin
potentiates methotrexate toxicity.
Interacting drug: Corticosteroids
increase risk of toxicity
Interacting drug: Co-trimoxazole
antifolate effect increased
Interacting drug: NSAIDs
increases methotrexate toxicity. Not really a problem with low dose oral use
Interacting drug: Penicillin
excretion of methotrexate decreased
Interacting drug: tetracyclines
increased risk of methotrexate toxicity