Drug & supplement interaction

Bismuth Nitrate + Phenytoin

Phenytoin brand names: Dilantin Kapseals, Dilantin, Di-Phen, Dilantin Infatabs, Phenytek, and others.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Bismuth Nitrate and Phenytoin in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Bismuth Nitrate and Phenytoin

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Phenytoin and Bismuth Nitrate in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

Worth understanding: our licensed dataset holds no drug-interaction record for Bismuth Nitrate at all — not against Phenytoin, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Bismuth Nitrate safety at a glance

Bismuth Nitrate overall Use caution Bismuth nitrate is not a standard supplement and can pose toxicity risks, so it should only be used under professional guidance.
Pregnancy Avoid There is not enough safety information, so it is best avoided during pregnancy.
Breastfeeding Avoid Safety while breastfeeding is unknown, so avoid use.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Phenytoin and Bismuth Nitrate? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Bismuth Nitrate and Phenytoin May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

  • Confusion Worth acting on Additional detail

    Bismuth Nitrate

    “Orally, bismuth nitrate may cause headache. Long-term use of bismuth nitrate has been associated with bismuth encephalopathy. One report describes a patient who developed confusion, restlessness, convulsions, hypertonia, hypoventilation, and fever after taking 30-40 grams of bismuth nitrate daily for 10-20 years to treat stomach troubles. The patient was comatose upon admission to the hospital.”

    Bismuth Nitrate · Natural Medicines adverse-effect record, reported in cluster headache.

    3 sources cited
    1. 100547. Bismuth nitrate; MSDS No. B3396 [Online]; Mallenckrodt Baker: Phillipsburg, NJ, December 8, 1996. https://hazard.com/msds/mf/baker/baker/files/b3396.htm (accessed December 27, 2019).
    2. 100540. - Jaeger A, Kopferschmitt J, Sauder Ph, Flesch F, Tournoud C. Diagnosis in clinical toxicology. In: Bolt HM, de Wolff FA, Henderson PT (eds) Medical Toxicology. Archives of Toxicology (Supplement). Berlin/Heidelberg, Germany: Springer-Verlag; 1992:29-39. PubMed
    3. 100550. Von Bose MJ, Zaudig M. Encephalopathy resembling Creutzfeldt-Jakob disease following oral, prescribed doses of bismuth nitrate. Br J Psychiatry. 1991;158:278-80. PubMed

    Phenytoin

    Listed in the ADVERSE REACTIONS section of the FDA label for Phenytoin. Read the label on DailyMed ›

  • Seizures Worth acting on Additional detail

    Bismuth Nitrate

    “Orally, bismuth nitrate may be converted to nitrites in the intestines, which may cause methemoglobinemia. Symptoms may include shortness of breath, cyanosis, headache, fatigue, changes in mental status, dizziness, and discoloration of the skin. In severe cases, dysrhythmias, convulsion, coma, or death may occur.”

    Bismuth Nitrate · Natural Medicines adverse-effect record, reported in cluster headache.

    2 sources cited
    1. 100547. Bismuth nitrate; MSDS No. B3396 [Online]; Mallenckrodt Baker: Phillipsburg, NJ, December 8, 1996. https://hazard.com/msds/mf/baker/baker/files/b3396.htm (accessed December 27, 2019).
    2. 101508. Raafat BM, Samir WA, Khader MH. Met-Hemoglobin concentration reduction and methemoglobin reductase enhancement after applying of alpha-tocopherol and selenium combination as a radio protector against ionizing radiation exposure. Wulfenia J. 2012;19(10):37

    Phenytoin

    Listed in the ADVERSE REACTIONS section of the FDA label for Phenytoin. Read the label on DailyMed ›

  • Anxiety or restlessness / Trouble sleeping / Fever / Nausea Additional detail

    Bismuth Nitrate

    Recorded for Bismuth Nitrate in the same Natural Medicines adverse-effect record shown under Confusion above.

    Phenytoin

    Listed in the ADVERSE REACTIONS section of the FDA label for Phenytoin. Read the label on DailyMed ›

  • Dizziness Additional detail

    Bismuth Nitrate

    Recorded for Bismuth Nitrate in the same Natural Medicines adverse-effect record shown under Confusion above.

    Phenytoin

    Listed in the ADVERSE REACTIONS section of the FDA label for Phenytoin. Read the label on DailyMed ›

  • Headache Additional detail

    Bismuth Nitrate

    “Orally, bismuth nitrate may cause loss of appetite, headache, methemoglobinemia, or kidney damage. Chronic use of bismuth nitrate may cause black spots on the gums, bad breath, salivation, and a "bismuth line." In rare cases, chronic use of bismuth may cause bismuth encephalopathy. Orally or topically, bismuth nitrate may cause mild skin irritation.”

    Bismuth Nitrate · Natural Medicines adverse-effect record, reported in cluster headache.

    5 sources cited
    1. 100540. - Jaeger A, Kopferschmitt J, Sauder Ph, Flesch F, Tournoud C. Diagnosis in clinical toxicology. In: Bolt HM, de Wolff FA, Henderson PT (eds) Medical Toxicology. Archives of Toxicology (Supplement). Berlin/Heidelberg, Germany: Springer-Verlag; 1992:29-39. PubMed
    2. 100547. Bismuth nitrate; MSDS No. B3396 [Online]; Mallenckrodt Baker: Phillipsburg, NJ, December 8, 1996. https://hazard.com/msds/mf/baker/baker/files/b3396.htm (accessed December 27, 2019).
    3. 100550. Von Bose MJ, Zaudig M. Encephalopathy resembling Creutzfeldt-Jakob disease following oral, prescribed doses of bismuth nitrate. Br J Psychiatry. 1991;158:278-80. PubMed
    4. 101507. Lewis RJ Sr. Hazardous Chemicals Desk Reference. 6th Edition. Hoboken, NJ: Wiley; 2008.
    5. 101508. Raafat BM, Samir WA, Khader MH. Met-Hemoglobin concentration reduction and methemoglobin reductase enhancement after applying of alpha-tocopherol and selenium combination as a radio protector against ionizing radiation exposure. Wulfenia J. 2012;19(10):37

    Phenytoin

    Listed in the ADVERSE REACTIONS section of the FDA label for Phenytoin. Read the label on DailyMed ›

Reported for Bismuth Nitrate but not commonly for Phenytoin: trouble concentrating, shortness of breath, reduced appetite and low mood.

Effects for Phenytoin come from the ADVERSE REACTIONS section of its FDA label; effects for Bismuth Nitrate come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

From our Q&A

Questions About Bismuth Nitrate or Phenytoin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Bismuth Nitrate or Phenytoin, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Phenytoin

This page covers Bismuth Nitrate only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phenytoin page lists 224 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Kava (major).

By severity: 9 major · 187 moderate · 28 minor.

From our pharmacist’s overview on the Phenytoin page

“Phenytoin (Dilantin) is a seizure medicine with a narrow therapeutic index, meaning small changes in its blood level can bring seizures back or tip over into toxicity, so I treat its supplement list with real seriousness. The biggest group, 78 ingredients, piles on sedation, and alcohol, kava, and GHB all rate major for exactly that re…”

Reviewed by 2 · Jul 18, 2026

Open the Phenytoin interaction page

One more smart check

Taking Bismuth Nitrate as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1 real supplement products containing Bismuth Nitrate, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Bismuth Nitrate. Even though Bismuth Nitrate itself has no known interaction with Phenytoin, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Bismuth Nitrate and Phenytoin Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Bismuth Nitrate
Steady interest

#1,325 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Phenytoin
Top half

#922 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Bismuth Nitrate reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Bismuth Nitrate and Phenytoin records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Bismuth Nitrate

What is Bismuth Nitrate?

  • Upset stomach and indigestion
  • Diarrhea
  • Wound and skin protection (topical)
  • Mild antiseptic

Bismuth nitrate is a bismuth-based chemical compound that was historically used for stomach complaints and as a mild topical antiseptic, but it is not a common modern dietary supplement and is rarely used today. Better-studied bismuth products (like bismuth subsalicylate) have largely replaced it, and bismuth nitrate carries safety concerns, so talk with a pharmacist or doctor before using any bismuth product.

Not applicable (a chemical bismuth compound, not a plant) · Compounded powders, topical preparations, and historically in some oral antacid or stomach formulas

An interaction check asks whether these two react with each other — it does not ask whether Bismuth Nitrate is a good idea for someone in your situation. Here is what our Bismuth Nitrate record says about it on its own.

Bismuth Nitrate: dosing

There is no established standard dose of bismuth nitrate as a supplement, and it is not a typical over-the-counter product. Because of this, no specific safe amount can be recommended here.If a product containing bismuth nitrate is available to you, follow the directions on the label exactly and do not exceed them.

From our Bismuth Nitrate monograph — the full record covers uses, side effects and every documented interaction.

Read the full Bismuth Nitrate monograph & all interactions
Medication

About Phenytoin

What Is Phenytoin Used For?

Brand names: Dilantin Kapseals, Dilantin, Di-Phen, Dilantin Infatabs, Phenytek, Dilantin injection

Phenytoin is used to treat and prevent seizures. The specific types covered depend on the formulation. Oral extended-release capsules (including Phenytek), chewable tablets (including Dilantin Infatabs and Phenytoin Infatabs), and oral suspension (including Dilantin-125) are used for tonic-clonic (grand mal) and psychomotor (temporal lobe) seizures; most oral forms also cover prevention and treatment of seizures occurring during or after neurosurgery. Chewable tablets and some capsule formulations also cover complex partial seizures.

Parenteral (injectable) phenytoin sodium is used for generalized tonic-clonic status epilepticus (a prolonged, life-threatening seizure emergency) and for prevention and treatment of seizures during neurosurgery. The IV form can also substitute short-term for oral phenytoin when a patient cannot take it by mouth.

Most-Reported Side Effects for Phenytoin

From FAERS, the FDA’s public side-effect reporting system (40,278 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Convulsion 3,522 reports
Seizure 3,095 reports
Toxicity to various agents 1,888 reports
Fall 1,604 reports
Dizziness 1,539 reports
See full Phenytoin drug information
Keep checking

Other Drugs & Bismuth Nitrate

Browse every other medication we’ve checked against Bismuth Nitrate — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

We also checked Bismuth Nitrate against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Bismuth Nitrate list.

See the full Bismuth Nitrate interactions page
See every supplement checked against Phenytoin, ranked by severity
Evidence & sources

Bismuth Nitrate References

The 6 references that drive our Bismuth Nitrate monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. - Jaeger A, Kopferschmitt J, Sauder Ph, Flesch F, Tournoud C. Diagnosis in clinical toxicology. In: Bolt HM, de Wolff FA, Henderson PT (eds) Medical Toxicology. Archives of Toxicology (Supplement). Berlin/Heidelberg, Germany: Springer-Verlag; 1992:29-39. PubMed
  2. Bismuth nitrate; MSDS No. B3396 [Online]; Mallenckrodt Baker: Phillipsburg, NJ, December 8, 1996. https://hazard.com/msds/mf/baker/baker/files/b3396.htm (accessed December 27, 2019).
  3. Saberi-Firoozi M, Massarrat S, Zare S, et al. Effect of triple therapy or amoxycillin plus omeprazole or amoxycillin plus tinidazole plus omeprazole on duodenal ulcer healing, eradication of Helicobacter pylori, and prevention of ulcer relapse over a 1-ye
  4. Von Bose MJ, Zaudig M. Encephalopathy resembling Creutzfeldt-Jakob disease following oral, prescribed doses of bismuth nitrate. Br J Psychiatry. 1991;158:278-80. PubMed
  5. Lewis RJ Sr. Hazardous Chemicals Desk Reference. 6th Edition. Hoboken, NJ: Wiley; 2008.
  6. Raafat BM, Samir WA, Khader MH. Met-Hemoglobin concentration reduction and methemoglobin reductase enhancement after applying of alpha-tocopherol and selenium combination as a radio protector against ionizing radiation exposure. Wulfenia J. 2012;19(10):37

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Bismuth Nitrate and Phenytoin Together: Common Questions

Is it safe to take Bismuth Nitrate with Phenytoin?
We do not list a known interaction between Bismuth Nitrate and Phenytoin. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Bismuth Nitrate and Phenytoin have any of the same side effects?
Yes — our sources link each of them separately to 8 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Does Phenytoin interact with any supplements?
Yes. Phenytoin has documented interactions with 224 supplements in our database — Bismuth Nitrate is not one of them. The Phenytoin interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Bismuth Nitrate monograph Uses, safety profile, and every drug interaction in one place Phenytoin drug information The full plain-English guide to this medication Phenytoin supplement interactions Every supplement checked against Phenytoin, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 6 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Phenytoin and Bismuth Nitrate?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.