Drug interactions
Bismuth subsalicylate + Tetracycline
Severity: Moderate
Bismuth subsalicylate and Tetracycline: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Bismuth in oral bismuth subsalicylate can bind tetracycline in the gut and reduce its absorption. This may lower antibiotic levels, although the two are used together in some H. pylori regimens with scheduled dosing.
What this interaction means in plain words
Bismuth subsalicylate and Tetracycline can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Bismuth subsalicylate belongs to Gastrointestinal Tract; Tetracycline belongs to Anti Bacterial.
Why it happens
Chelation of tetracycline by bismuth in the gastrointestinal tract reduces absorption.
What to do
Where separate dosing is possible, space doses by 2 to 3 hours; in established H. pylori regimens follow the protocol dosing schedule.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Bismuth subsalicylate
- Bismuth subsalicylate + Dichlorphenamide Major
- Bismuth subsalicylate + Warfarin Major
- Acetylsalicylic acid + Bismuth subsalicylate Moderate
- Amlodipine-benazepril + Bismuth subsalicylate Moderate
- Aspirin / citric acid / sodium bicarbonate + Bismuth subsalicylate Moderate
- Aspirin rectal + Bismuth subsalicylate Moderate
Other interactions of Tetracycline
- Acitretin + Tetracycline Contraindicated
- Methoxyflurane + Tetracycline Contraindicated
- Isotretinoin + Tetracycline Major
- Palovarotene + Tetracycline Major
- Strontium ranelate + Tetracycline Major
- Tetracycline + Tretinoin Major
Frequently asked questions
Can I take Bismuth subsalicylate with Tetracycline?
MediHelp rates the interaction as moderate. Bismuth subsalicylate and Tetracycline can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Bismuth in oral bismuth subsalicylate can bind tetracycline in the gut and reduce its absorption. This may lower antibiotic levels, although the two are used together in some H. pylori regimens with scheduled dosing.
How serious is the interaction between Bismuth subsalicylate and Tetracycline?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Where separate dosing is possible, space doses by 2 to 3 hours; in established H. pylori regimens follow the protocol dosing schedule.
What other medicines interact with Bismuth subsalicylate?
MediHelp also lists interactions of Bismuth subsalicylate with, for example, Dichlorphenamide, Warfarin, Acetylsalicylic acid. The full list is on the Bismuth subsalicylate page.
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