dihydrofolate reductase
2 interactions related to dihydrofolate reductase
lamotrigine + folate
In a randomized controlled trial of bipolar depression (CEQUEL), adding folic acid to lamotrigine appeared to blunt lamotrigine's antidepressant benefit, an effect seen mainly in people carrying the COMT Met allele. The interaction is pharmacodynamic, not pharmacokinetic, so lamotrigine blood levels stay unchanged. The exact mechanism is not established, and the signal is limited to bipolar depression rather than epilepsy.
methotrexate + folate
Methotrexate works by blocking the enzyme that recycles folate into its active form, which depletes folate in normal tissues and drives common side effects such as nausea, mouth sores, and elevated liver enzymes. Folic acid supplementation reduces these side effects without compromising efficacy at the doses used for autoimmune disease, but it should not be taken on the same day as methotrexate, and it should never be added on your own when methotrexate is used for cancer.