According to a few reports, folate can occasionally cause an increase of seizures in those with epilepsy and may interfere with the antiseizure drug phenytoin. Maximum safe dosages have not been established for young children or pregnant or nursing women. Contrary to some reports, individuals who are taking the drug methotrexate for rheumatoid arthritis, juvenile rheumatoid arthritis, or psoriasis can safely take folate supplements at the same time. However, if you are taking methotrexate for any other purpose, do not take folate except on the advice of a physician. You may need to take extra folate.
Physician supervision is essential.
You can use folate without fear of decreasing the medication's effects. However, if you are taking methotrexate for other purposes, do not take folate except on the advice of a physician. More folic acid for everyone, now. Werbach M. Foundations of nutritional medicine. Lampi B. Bioavailability of folate following ingestion of cholestyramine in the rat.