NutriStack
Lamotrigine and Vitamin B9, a caution.
Lamotrigine is a folate antagonist that inhibits dihydrofolate reductase. Long-term use may reduce folate levels. However, folate supplementation may reduce lamotrigine levels, potentially decreasing seizure control or mood stabilization.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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At a glance
- Substances
- Lamotrigine and Vitamin B9
- Pair type
- Caution
- Evidence (highest tier)
- Moderate
- Source citations
- 1 source
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Moderate evidence
Caution
What is happening. Lamotrigine is a folate antagonist that inhibits dihydrofolate reductase. Long-term use may reduce folate levels. However, folate supplementation may reduce lamotrigine levels, potentially decreasing seizure control or mood stabilization.
Mechanism. Lamotrigine inhibits dihydrofolate reductase, reducing folate availability. Conversely, folic acid may enhance lamotrigine glucuronidation via UGT1A4 induction, lowering lamotrigine plasma levels.
Recommendation. If folate supplementation is needed (especially in pregnancy), monitor lamotrigine levels and seizure control closely. Low-dose folate (400-1000mcg) is generally safer than high doses. Discuss with your neurologist before starting.
Sources (1)
Stack Score
How this pair moves the number.
Effect on the composite score
If both Lamotrigine and Vitamin B9 are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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