Folidyn Drug Interactions

Folic acid decreases phenytoin and barbiturate anti-epileptic plasma concentrations. Correction of folate deficiency may result in potential loss of seizure control.
Prolonged phenytoin use induces folate deficiency. A similar mechanism may occur with other anti-seizure drugs including sodium valproate, carbamazepine and barbiturate.
Folic acid absorption may be inhibited by sulphasalazine.
The antibacterial co-trimoxazole (i.e. trimethoprim, sulfamethoxazole) may interfere with folate metabolism.
Folate may enhance the efficacy of lithium therapy.
Methotrexate is a folic acid antagonist. It inhibits the enzyme dihydrofolate reductase resulting to suppression of purine and pyrimidine production during DNA synthesis. Folate deficiency may result from prolonged use of methotrexate.
Folic acid supplementation may decrease methotrexate plasma concentration.
Nitrous oxide anesthetics may induce acute folic acid deficiency. This is likely due to failure of intracellular transport and enhanced excretion of folate.