Folic Acid + Methotrexate

MediHelp rates the interaction as moderate. Folic Acid and Methotrexate can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Folic acid is routinely co-prescribed with low-dose weekly methotrexate to reduce nausea, mouth ulcers, and liver enzyme elevations without meaningfully reducing efficacy in rheumatoid arthritis or psoriasis. In oncology, folate supplementation could theoretically reduce the antineoplastic effect of methotrexate, particularly at high doses, so it is not given outside protocols.

MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: For low-dose weekly methotrexate in rheumatologic or dermatologic disease, give folic acid at a typical dose of 5 mg weekly or 1 mg daily, commonly on a day other than the methotrexate dose. Monitor blood counts, liver enzymes, and renal function regularly, and assess disease control.

MediHelp also lists interactions of Methotrexate with, for example, Acitretin, Adenovirus types 4 and 7 live, Influenza virus vaccine quadrivalent intranasal. The full list is on the Methotrexate page.