Herb & supplement monograph

Vitamin B6 Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Vitamin B6 interacts with medications. The heart of this page is the interaction list — every drug Vitamin B6 is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Vitamin B6 is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Vitamin B6 Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Vitamin B6 drug interaction appears low for most people. None of the listed interactions are rated major, and even the moderate ones rest mainly on preliminary or theoretical evidence rather than well-proven effects in people.

Interactions deserving the most attention

The clearest concerns involve high doses of vitamin B6 with the seizure medicines phenobarbital and phenytoin, where early clinical evidence suggests B6 around 200 mg daily may lower drug levels and weaken seizure control, so high doses are best avoided with these medicines. High-dose B6 may also add to the effect of blood pressure medications, since some research shows it can lower blood pressure. With amiodarone, early research suggests B6 might worsen sun sensitivity rather than protect against it.

What the rest of the list means

A long interaction list does not mean every combination is harmful. Most of these entries reflect possible or theoretical effects that have not been confirmed in people, and some predicted problems do not play out in practice. For example, B6 can reduce the effect of levodopa taken alone, but this is unlikely to matter for the many people who take levodopa combined with carbidopa.

Check your medications against Vitamin B6

Based on HelloPharmacist’s Vitamin B6 interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Vitamin B6

210 medications have a known interaction with Vitamin B6, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Vitamin B6 using our pharmacist-reviewed interaction data.

AI summaries are generated from our Vitamin B6 interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Vitamin B6 combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Vitamin B6 affects

Every type of medication (drug category) Vitamin B6 is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 5 drug categories Vitamin B6 interacts with

Amiodarone (cordarone)Antihypertensive DrugsPhenobarbital (luminal)Phenytoin (dilantin)Levodopa

Amiodarone (Cordarone)

Theoretically, vitamin B6 might increase the photosensitivity caused by amiodarone.
Despite initial case reports suggesting that pyridoxine may have a protective effect against amiodarone-induced photosensitivity, preliminary clinical research suggests that pyridoxine may actually exacerbate this adverse effect.

Likelihood Possible Evidence B

Antihypertensive Drugs

Theoretically, vitamin B6 may have additive effects when used with antihypertensive drugs.
Research in hypertensive rats shows that vitamin B6 can decrease systolic blood pressure. Similarly, clinical research in patients with hypertension shows that taking high doses of vitamin B6 may reduce systolic and diastolic blood pressure, possibly by reducing plasma levels of epinephrine and norepinephrine.

Likelihood Possible Evidence B

Phenobarbital (Luminal)

High doses of vitamin B6 may reduce the levels and clinical effects of phenobarbital.
Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenobarbital, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenobarbital to avoid high doses of vitamin B6.

Likelihood Possible Evidence D

Phenytoin (Dilantin)

High doses of vitamin B6 may reduce the levels and clinical effects of phenytoin.
Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenytoin, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenytoin to avoid high doses of vitamin B6.

Likelihood Possible Evidence D

Levodopa

Vitamin B6 may increase the metabolism of levodopa when taken alone, but not when taken in conjunction with carbidopa.
Vitamin B6 (pyridoxine) enhances the metabolism of levodopa, reducing its clinical effects. However, this interaction does not occur when carbidopa is used concurrently with levodopa (Sinemet). Therefore, it is not likely to be a problem in most people.

Likelihood Unlikely Evidence D

Monograph

Vitamin B6: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Vitamin B6 (pyridoxine) is an essential water-soluble vitamin that your body needs for metabolism, brain function, and making red blood cells. It is best known for helping with pregnancy-related nausea and may help some people with PMS, but taking very high doses for long periods can cause nerve damage. Get most of your B6 from food, and check with a pharmacist or doctor before taking high-dose supplements.

Common forms: Tablets, capsules, softgels, liquid drops, part of B-complex and multivitamins

People commonly use it for

Morning sickness in pregnancy
Premenstrual syndrome (PMS)
Preventing or treating B6 deficiency
Nerve health and metabolism support
Nausea

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Safe at normal amounts from food and standard supplements, but high doses over time can harm nerves.

PregnancyLikely Safe

When used orally and appropriately. A special sustained-release product providing vitamin B6 (pyridoxine) 75 mg daily is FDA-approved for use in pregn...

Read the full pregnancy detail

BreastfeedingLikely Safe

When used orally in doses not exceeding the tolerable upper intake level (UL) of vitamin B6 in the form of pyridoxine 80 mg daily for those aged 14-18...

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Vitamin B6 is an essential, water-soluble vitamin. The term covers several related compounds, the most common supplement form being pyridoxine. Your body converts these forms into an active form called pyridoxal 5'-phosphate (PLP), which helps run many chemical reactions in the body.

Because B6 is water-soluble, your body does not store large amounts of it, so you need a regular supply from food. It is found in many everyday foods such as poultry, fish, potatoes, chickpeas, bananas, and fortified cereals. Most people who eat a balanced diet get enough.

People take B6 supplements for several reasons, including treating a deficiency, easing morning sickness during pregnancy, and managing symptoms of PMS. It is sold on its own and as part of B-complex and multivitamin products.

How it works

Vitamin B6 is turned into its active form, pyridoxal 5'-phosphate (PLP), which acts as a helper (a "coenzyme") in more than 100 enzyme reactions. These reactions are involved in breaking down proteins and amino acids, making neurotransmitters (brain chemicals that affect mood and sleep), forming hemoglobin for red blood cells, and supporting blood sugar control.

Its role in making brain chemicals like serotonin and GABA is one proposed reason it may affect mood, nausea, and PMS symptoms. B6 also helps process homocysteine, an amino acid in the blood.

While these biological roles are well established, that does not automatically mean extra B6 helps healthy people who already get enough. Much of the support for high-dose use is limited or comes from small studies.

Effectiveness

Does Vitamin B6 work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 65 uses evaluated

3 Effective 1 Likely effective 4 Possibly effective 9 Leans ineffective 48 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

Effective Pyridoxine-dependent epilepsy