Supplements and Carbamazepine.
Carbamazepine, sold under the brand name Tegretol, is an antiepileptic drug. Several agents in this class are strong CYP inducers or inhibitors.
Carbamazepine is an antiepileptic medicine. The class is heterogeneous. Enzyme inducers (carbamazepine, phenytoin, phenobarbital) drop plasma levels of many medicines given alongside. Enzyme inhibitors (valproate) raise them. The newer agents (levetiracetam, lacosamide) have quieter interaction profiles. The supplement interactions of greatest clinical importance. St John's Wort is excluded with the inducer antiepileptics on top of an already complex CYP picture. Folate at high doses competes with the folate depletion that antiepileptics drive, in a way that needs neurology team input rather than community pharmacy. Calcium and vitamin D status matter because inducer antiepileptics drive bone density loss over years; the SANAD bone substudy data is the relevant evidence base. Pregnancy planning on an antiepileptic regimen always runs through the neurology team, because of folate timing and the teratogenicity profile specific to each agent (valproate carries the highest, levetiracetam much lower).
Below are the 4 documented pairs we have explicitly assessed against Carbamazepine in the Distil database: 4 amber. The pairs cluster around 4 mechanisms: Folate-anticonvulsant (two-way), CYP induction, CYP3A4 inhibition, and Drug depletes the supplement. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not on this list is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by supplement, and the missing-item form at the bottom of the page routes any uncatalogued supplement into our next curation pass.
Documented interactions
Last reviewed 21 June 2026. Each interaction below lists the evidence its assessment drew on: some rest on studies of the exact pair, others on mechanism evidence, where a citation may support one part of the reasoning rather than the exact combination. The evidence line on each entry says which.
Folate-anticonvulsant (two-way)
Amber Does Folate interact with ?
Carbamazepine tends to lower folate levels over time, so people on it for a long time often run low on folate, which can also push up a blood marker called homocysteine. This usually works in the direction of needing folate rather than avoiding it, and folate is often supplemented on purpose in people on carbamazepine. As with other epilepsy medicines, it is sensible to start folate with your prescriber's knowledge so your levels and seizure control can be kept under review. Let whoever manages your epilepsy know before you start or stop folate.
Evidence: Supported by human study data.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
CYP induction
Amber Does St John's Wort interact with ?
Carbamazepine is a strong enzyme-inducer that already speeds up its own breakdown, and St John's Wort works the same way. In the one controlled study, adding St John's Wort did not lower carbamazepine levels further, but combining two enzyme-inducers is still best avoided without specialist input, especially when carbamazepine is being started or its dose changed. Do not start or stop St John's Wort while taking carbamazepine without telling whoever prescribes it.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
CYP3A4 inhibition
Amber Does Resveratrol interact with ?
Resveratrol can raise blood levels of carbamazepine by slowing how the body clears it, which may increase side effects such as dizziness, drowsiness, or unsteadiness. Carbamazepine has a narrow safe range, so tell your epilepsy or prescribing team before taking resveratrol.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Drug depletes the supplement
Amber Does Vitamin D3 interact with ?
Carbamazepine speeds up the liver enzymes that break vitamin D down, so people on it for a long time tend to have lower vitamin D levels and, over years, a higher risk of weaker bones. This works the opposite way to most interactions: the medicine lowers your vitamin D rather than the supplement affecting the medicine. Taking a vitamin D supplement is generally the recommended response, and many prescribers check vitamin D and bone health in people on long-term carbamazepine.
Evidence: Supported by human study data.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope (food-supplement interactions only; for drug-drug interactions, the BNF is authoritative). Use the checker below to surface any supplement, and submit a missing item if you take something we have not catalogued.
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How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
Read the full methodologyA full supplement review, built around you, not a generic stack.
The free checker answers one interaction question at a time. A Distil report reviews the bigger picture: your goals, diet, medications, current supplements and any blood results you provide, then shows what appears worth keeping, changing, adding or leaving out.
- what your diet already covers, so you are not adding a capsule for something food is already handling
- which evidence-graded compounds are worth considering for your goals, and which were considered but left out
- what to keep, change or stop from what you already take, plus the order to introduce anything new
- how your medications and complete supplement stack fit together, with daily timing and a clear point for reassessment
The interaction check is one section of the full report. You also get the reasoning behind each recommendation and the evidence references used.
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