NutriStack
Carbamazepine and Vitamin B9, a caution.
Carbamazepine reduces folate levels by inhibiting intestinal absorption and increasing hepatic folate catabolism. Folate deficiency can cause megaloblastic anemia. However, high-dose folate supplementation may reduce carbamazepine levels.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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What the row says.
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At a glance
- Substances
- Carbamazepine and Vitamin B9
- Pair type
- Caution
- Evidence (highest tier)
- Strong
- 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 · Strong evidence
Caution
What is happening. Carbamazepine reduces folate levels by inhibiting intestinal absorption and increasing hepatic folate catabolism. Folate deficiency can cause megaloblastic anemia. However, high-dose folate supplementation may reduce carbamazepine levels.
Mechanism. Carbamazepine induces folate-metabolizing enzymes and impairs intestinal folate absorption. It also increases demand for folate in hepatic drug conjugation reactions. Conversely, folate may enhance carbamazepine glucuronidation.
Recommendation. Low-dose folate supplementation (400-1000mcg/day) is generally recommended during carbamazepine therapy. Avoid high-dose folate (>5mg) as it may reduce carbamazepine levels. Monitor CBC and drug levels.
Sources (1)
Stack Score
How this pair moves the number.
Effect on the composite score
If both Carbamazepine 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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