Drug & supplement interaction

Bismuth + Methazolamide

Methazolamide brand name: Neptazane.

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 and Methazolamide 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 and Methazolamide

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 Methazolamide and Bismuth 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.

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 safety at a glance

Bismuth overall Use caution Generally safe for short-term use, but most products contain salicylate and should not be overused.
Pregnancy Avoid Bismuth subsalicylate is generally avoided in pregnancy, especially later, due to its salicylate content.
Breastfeeding Use caution Salicylate can pass into breast milk, so check with a doctor before use while nursing.

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

Still wondering about combining Methazolamide and Bismuth? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Methazolamide

Interactions in our licensed database are recorded against drug classes, not just single drug names. Methazolamide is filed under 5 classifications — including carbonic anhydrase inhibitors, diuretic drugs, antihypertensive drugs. Bismuth has documented interactions with 4 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate), aspirin (moderate) and omeprazole (prilosec) (moderate) — and none of Methazolamide’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Bismuth Does Interact With Other Medications

Bismuth has 125 moderate known drug interactions in our database — Methazolamide isn’t one of them. If you take anything else, check it against the full list below.

Moderate 125 No known interaction 2,705 (incl. Methazolamide)
Taking anything else?

Check Another of Your Medications Against Bismuth

Covers the 2,830 medications we’ve checked against Bismuth. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Bismuth and Methazolamide 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. 3 of them are worth acting on rather than waiting out — marked below.

  • Confusion / Seizures Worth acting on Additional detail

    Bismuth

    “Orally, multiple cases of bismuth-related neurotoxicity have been reported. In general, the risk of neurotoxicity from bismuth salts appears to be greater for colloidal bismuth than other forms due to the greater bioavailability of colloidal bismuth. In most cases, the neurotoxicity results from excessive use of bismuth salts over prolonged time periods (up to 30 years).”

    Bismuth · Natural Medicines adverse-effect record, reported in anxiety.

    6 sources cited
    1. 25775. Mishkin, S. Intriguing gastrointestinal properties of bismuth: a folk remedy brought into the realm of clinical and investigative medicine. Can J Gastroenterol 1998;12(8):569-570. PubMed
    2. 29942. Supino-Viterbo V, Sicard C, Risvegliato M, Rancurel G, Buge A. Toxic encephalopathy due to ingestion of bismuth salts: clinical and EEG studies of 45 patients. J Neurol Neurosurg Psychiatry 1977;40(8):748-52. PubMed
    3. 25770. Cengiz, N., Uslu, Y., Gok, F., and Anarat, A. Acute renal failure after overdose of colloidal bismuth subcitrate. Pediatr Nephrol 2005;20(9):1355-1358. PubMed
    4. 29946. Masannat Y, Nazer E. Pepto bismuth associated neurotoxicity: A rare side effect of a commonly used medication. W V Med J 2013;109(3):32-4.
    5. 106807. Halani S, Wu PE. Salicylate toxicity from chronic bismuth subsalicylate use. BMJ Case Rep 2020;13(11):e236929. PubMed
    6. 97817. Tsay FW, Wu DC, Yu HC, et al. A randomized controlled trial shows that both 14-day hybrid and bismuth quadruple therapies cure most patients with Helicobacter pylori infection in populations with moderate antibiotic resistance. Antimicrob Agents Chemother

    Methazolamide

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

  • Anemia Worth acting on Additional detail

    Bismuth

    “Orally, aplastic anemia has been reported as a potential side effect of bismuth salts. Lymphoid follicles are a reported side effect in a clinical trial investigating colloidal bismuth subcitrate in combination with tetracycline and furazolidone. However, the effect of bismuth alone is unclear. Excessive intake of bismuth subnitrate may cause methemoglobinemia.”

    Bismuth · Natural Medicines adverse-effect record, reported in anemia.

    4 sources cited
    1. 26338. Moeschlin, S. [Clinical-hematological demonstrations: aplastic anemia, acute leukemias, polyneuropathy in Waldenstrom's disease, acute porphyria]. Schweiz Med Wochenschr 1975;105(40):1289-1298.
    2. 26335. Araujo Castillo, R., Pinto Valdivia, J. L., Ramirez, D., Cok Garcia, J., and Bussalleu Rivera, A. [New ultrashort scheme for helicobacter pylori infection eradication using tetracyline, furazolidone and colloidal bismuth subcitrate in dyspeptic patients w
    3. 29947. James JA. Acute renal failure due to a bismuth preparation. Calif Med 1968;109(4):317-9.
    4. 29948. Jacobsen JB, Hüttel MS. [Methemhemoglobinemia after excessive intake of a subnitrate containing antacid]. Ugeskr Laeger 1982;144(32):2349-50.

    Methazolamide

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

  • Tiredness reported in 18.3% of FDA reports for Methazolamide Additional detail

    Bismuth

    “Orally, cases of nephrotoxicity or acute kidney failure resulting from short-term exposure to high levels of bismuth salts, including colloidal bismuth subcitrate (De-Nol) and bismuth sodium triglycollamate (Bistrimate), have been reported.”

    Bismuth · Natural Medicines adverse-effect record, reported in myasthenia gravis.

    2 sources cited
    1. 25770. Cengiz, N., Uslu, Y., Gok, F., and Anarat, A. Acute renal failure after overdose of colloidal bismuth subcitrate. Pediatr Nephrol 2005;20(9):1355-1358. PubMed
    2. 29947. James JA. Acute renal failure due to a bismuth preparation. Calif Med 1968;109(4):317-9.

    Methazolamide

    Listed in the ADVERSE REACTIONS section of the FDA label for Methazolamide, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Numbness or tingling Additional detail

    Bismuth

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

    Methazolamide

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

  • Drowsiness Additional detail

    Bismuth

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

    Methazolamide

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

  • Stomach upset Additional detail

    Bismuth

    “Orally, bismuth that is not absorbed is excreted in the feces as insoluble salts and may cause stools to appear grayish black. Also, bismuth may cause the tongue to turn black due to macular lingual pigmentation.”

    Bismuth · Natural Medicines adverse-effect record, reported in constipation.

    6 sources cited
    1. 25770. Cengiz, N., Uslu, Y., Gok, F., and Anarat, A. Acute renal failure after overdose of colloidal bismuth subcitrate. Pediatr Nephrol 2005;20(9):1355-1358. PubMed
    2. 26333. DuPont, H. L., Ericsson, C. D., Johnson, P. C., Bitsura, J. A., DuPont, M. W., and de la Cabada, F. J. Prevention of travelers' diarrhea by the tablet formulation of bismuth subsalicylate. JAMA 1987;257(10):1347-1350. DOI
    3. 29957. Ford AC, Malfertheiner P, Giguere M, et al. Adverse events with bismuth salts for Helicobacter pylori eradication: systematic review and meta-analysis. World J Gastroenterol 2008;14(48):7361-70. PubMed
    4. 101113. Zaveri H, Surve A, Cottam D, et al. Does bismuth subgallate affect smell and stool Character? A randomized double-blinded placebo-controlled trial of bismuth subgallate on loop duodenal switch patients with complaints of smelly stools and diarrhea. Obes S PubMed
    5. 29943. Cohen PR. Black tongue secondary to bismuth subsalicylate: case report and review of exogenous causes of macular lingual pigmentation. J Drugs Dermatol 2009;8(12):1132-5.
    6. 29944. Ioffreda MD, Gordon CA, Adams DR, Naides SJ, Miller JJ. Black tongue. Arch Dermatol 2001;137(7):968-9.

    Methazolamide

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

  • Diarrhea / Nausea Additional detail

    Bismuth

    “Orally, bismuth salts are generally well tolerated when taken alone or in combination with antibiotics.

    Most Common Adverse Effects:

    Orally: Change in taste perception, discolored stools or tongue, dizziness, gastrointestinal symptoms, such as nausea and diarrhea, and headache.

    Serious Adverse Effects (Rare):

    Orally: After large doses or chronic use, kidney failure and encephalopathy have been reported.”

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

    Methazolamide

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

  • Vomiting Additional detail

    Bismuth

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

    Methazolamide

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

Reported for Bismuth but not commonly for Methazolamide: kidney problems, a change in taste, memory problems and stomach pain.

Effects for Methazolamide come from the ADVERSE REACTIONS section of its FDA label; effects for Bismuth come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 339 voluntary FDA FAERS reports for Methazolamide that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Everything else you take

See Every Supplement That Interacts With Methazolamide

This page covers Bismuth only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Methazolamide page lists 218 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Lithium (major) and Oleander (major).

By severity: 7 major · 187 moderate · 24 minor.

From our pharmacist’s overview on the Methazolamide page

“Methazolamide (Neptazane) treats glaucoma by lowering pressure inside the eye, and because it also has mild water-pill effects it can nudge blood pressure and potassium on its own. That is exactly where most of the 218 supplements on this page press, and the list earns real caution.”

Reviewed by 2 · Jul 18, 2026

Open the Methazolamide interaction page

One more smart check

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

We hold 65 real supplement products containing Bismuth, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Bismuth. Even though Bismuth itself has no known interaction with Methazolamide, 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 and Methazolamide 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
Steady interest

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

29 days ago today
Medication Methazolamide
Steady interest

#1,703 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 reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Bismuth and Methazolamide 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

What is Bismuth?

  • Upset stomach and indigestion
  • Diarrhea
  • Heartburn and nausea
  • Helicobacter pylori treatment (with other drugs)
  • Traveler's diarrhea prevention

Bismuth is a metallic element used in medicine mostly as bismuth subsalicylate (the active ingredient in some well-known stomach remedies) to ease upset stomach, heartburn, nausea, and diarrhea. It is generally well tolerated for short-term use, but it can cause harmless black stools or a dark tongue, and because most products contain salicylate, it carries cautions similar to aspirin. Always follow the label and check with a pharmacist before regular use.

Mineral element (not a plant); used as bismuth salts · Chewable tablets, caplets, liquid suspensions (commonly as bismuth subsalicylate)

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

Bismuth: dosing

There is no single "supplement" dose of bismuth. The right amount depends on the specific product and the reason for use. Always follow the directions on the package label for the product you have, and do not exceed the maximum daily amount listed.For medical uses such as H. pylori treatment, dosing is set by a doctor as part of a multi-drug regimen. Do not use bismuth products for more than a couple of days for diarrhea without checking with a healthcare provider.

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

Read the full Bismuth monograph & all interactions
Medication

About Methazolamide

What Is Methazolamide Used For?

Brand name: Neptazane

Methazolamide tablets are used to treat eye conditions where lowering intraocular pressure (pressure inside the eye) is expected to help. These include chronic open-angle glaucoma and secondary glaucoma.

Methazolamide tablets are also used before surgery in acute angle-closure glaucoma, when reducing eye pressure ahead of the procedure is needed. Note that long-term use in angle-closure glaucoma is not appropriate.

Most-Reported Side Effects for Methazolamide

From FAERS, the FDA’s public side-effect reporting system (339 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 41 reports
Dizziness 29 reports
Dyspnea 28 reports
Headache 28 reports
Blood pressure increased 22 reports
See full Methazolamide drug information
Keep checking

Other Drugs & Bismuth

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

0Major
125Moderate
0Minor
2,704No known interaction
125 Moderate 2,704 No interaction
Moderate

125 interactions

Showing 60 of 125 moderate interactions — see all 125 on the Bismuth page.

No interaction 2,704 drugs checked — show the list

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

Showing the 60 most looked-up of 2,704 medications checked with no known interaction — see the full Bismuth list.

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

Bismuth References

The 36 references that drive our Bismuth 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. Cengiz, N., Uslu, Y., Gok, F., and Anarat, A. Acute renal failure after overdose of colloidal bismuth subcitrate. Pediatr Nephrol 2005;20(9):1355-1358. PubMed
  2. Callanan, V., Curran, A. J., Smyth, D. A., and Gormley, P. K. The influence of bismuth subgallate and adrenaline paste upon operating time and operative blood loss in tonsillectomy. J Laryngol Otol 1995;109(3):206-208. PubMed
  3. Mishkin, S. Intriguing gastrointestinal properties of bismuth: a folk remedy brought into the realm of clinical and investigative medicine. Can J Gastroenterol 1998;12(8):569-570. PubMed
  4. GOELTNER, E. [Versenate treatment of alopecia following bismuth therapy]. Z Haut Geschlechtskr 1961;31:164-169.
  5. Hoffman, J. S., Katz, L. M., and Cave, D. R. Efficacy of a 1-week regimen of ranitidine bismuth citrate in combination with metronidazole and clarithromycin for Helicobacter pylori eradication. Aliment Pharmacol Ther 1999;13(4):503-506.
  6. Scott, B. B. Bismuth-containing single-antibiotic 1-week triple therapy for Helicobacter pylori eradication. Aliment Pharmacol Ther 1998;12(3):277-279.
  7. Sontag, S. J., O'Connell, S., Schnell, T., Chejfec, G., Seidel, J., and Sonnenberg, A. Reduced symptoms and need for antisecretory therapy in veterans 3 years after Helicobacter pylori eradication with ranitidine bismuth citrate/amoxicillin/clarithromycin PubMed
  8. Chey, W. D., Fisher, L., Elta, G. H., Barnett, J. L., Nostrant, T., DelValle, J., Hasler, W. L., and Scheiman, J. M. Bismuth subsalicylate instead of metronidazole with lansoprazole and clarithromycin for Helicobacter pylori infection: a randomized trial.
  9. Kaviani, M. J., Malekzadeh, R., Vahedi, H., Sotoudeh, M., Kamalian, N., Amini, M., and Massarrat, S. Various durations of a standard regimen (amoxycillin, metronidazole, colloidal bismuth sub-citrate for 2 weeks or with additional ranitidine for 1 or 2 we
  10. Gisbert, J. P., Marcos, S., Gisbert, J. L., and Pajares, J. M. High efficacy of ranitidine bismuth citrate, amoxicillin, clarithromycin and metronidazole twice daily for only five days in Helicobacter pylori Eradication. Helicobacter 2001;6(2):157-162.
  11. Nijevitch, A. A., Farztdinov, K. M., Sataev, V. U., Khasanov, R. Sh., Katayev, V. A., Khusnutdinov, S. M., Akhunov, E. D., and Kazykhanov, N. S. Helicobacter pylori infection in childhood: results of management with ranitidine bismuth citrate plus amoxici
  12. Bujanda, L., Sanchez, A., Iriondo, C., Santos, A., Cosme, A., and Munoz, C. [Comparative study of the eradication of Helicobacter pylori: ranitidine bismuth citrate versus omeprazole plus two antibiotics for seven days]. An Med Interna 2001;18(7):361-363.
  13. Wilhelmsen, I., Weberg, R., Berstad, K., Hausken, T., Hundal, O., and Berstad, A. Helicobacter pylori eradication with bismuth subnitrate, oxytetracycline and metronidazole in patients with peptic ulcer disease. Hepatogastroenterology 1994;41(1):43-47.
  14. DuPont, H. L., Ericsson, C. D., Johnson, P. C., Bitsura, J. A., DuPont, M. W., and de la Cabada, F. J. Prevention of travelers' diarrhea by the tablet formulation of bismuth subsalicylate. JAMA 1987;257(10):1347-1350. DOI
  15. Pozzato, P., Zagari, M., Cardelli, A., Catalano, F. A., Giglio, A., Lami, F., Pilotto, A., Scarpulla, G., Spadaccini, A., Susi, D., Tosatto, R., Olivieri, A., Bazzoli, F., and Roda, E. Ranitidine bismuth citrate plus clarithromycin 7-day regimen is effect

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 and Methazolamide Together: Common Questions

Is it safe to take Bismuth with Methazolamide?
We do not list a known interaction between Bismuth and Methazolamide. 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 and Methazolamide have any of the same side effects?
Yes — our sources link each of them separately to 10 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.
How was the Bismuth and Methazolamide combination checked?
Interactions in our licensed database are recorded against drug classes. Methazolamide is filed under 5 classifications, and Bismuth has documented interactions with 4 drug classes — none of Methazolamide's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Bismuth interact with any other medications?
Yes. Bismuth has 125 documented drug interactions in our database — Methazolamide is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Methazolamide interact with any supplements?
Yes. Methazolamide has documented interactions with 218 supplements in our database — Bismuth is not one of them. The Methazolamide 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 monograph Uses, safety profile, and every drug interaction in one place Methazolamide drug information The full plain-English guide to this medication Methazolamide supplement interactions Every supplement checked against Methazolamide, 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 36 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Methazolamide and Bismuth?

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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.