Bismuth subcitrate, metronidazole, and tetracycline and Demeclocycline interaction
Bismuth subcitrate, metronidazole, and tetracycline and Demeclocycline: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Demeclocycline (Demeclocycline Hydrochloride) label · effective 2025-12-11
CONTRAINDICATIONS This drug is contraindicated in persons who have shown hypersensitivity to any of the tetracyclines or any of the components of the product formulation.
TETRACYCLINE DRUGS, THEREFORE, SHOULD NOT BE USED DURING TOOTH DEVELOPMENT UNLESS OTHER DRUGS ARE NOT LIKELY TO BE EFFECTIVE OR ARE CONTRAINDICATED.
Since bacteriostatic drugs may interfere with the bactericidal action of penicillins, it is advisable to avoid giving tetracycline-class drugs in conjunction with penicillin.
The concurrent use of tetracyclines and methoxyflurane has been reported to result in fatal renal toxicity.
A decrease in fibula growth rate has been observed in premature human infants given oral tetracycline in doses of 25 mg/kg every six hours.
From the Bismuth subcitrate, metronidazole, and tetracycline (Bismuth Subcitrate Potassium, Metronidazole and Tetracycline Hydrochloride) label · effective 2026-04-13
As with other antibacterial drugs, use of tetracycline hydrochloride may result in overgrowth of nonsusceptible organisms, including fungi.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.