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