Drug interactions
Demeclocycline + Magnesium
Severity: Moderate
Demeclocycline and Magnesium: 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
Magnesium forms insoluble chelates with tetracyclines such as demeclocycline in the gut, reducing absorption. This may cause antibiotic treatment failure.
What this interaction means in plain words
Demeclocycline and Magnesium 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.
Why it happens
Chelation of demeclocycline by divalent magnesium cations in the GI tract reduces absorption.
What to do
Give demeclocycline at least 2 hours before or 4 hours after oral magnesium products. Alternatively, use a non-chelating antibiotic.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Demeclocycline and Magnesium, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Magnesium
- Ciprofloxacin + Magnesium Major
- Magnesium + Pancuronium Major
- Magnesium + Rocuronium Major
- Magnesium + Vecuronium Major
- Amikacin + Magnesium Moderate
- Amphotericin b deoxycholate + Magnesium Moderate
Frequently asked questions
Can I take Demeclocycline with Magnesium?
MediHelp rates the interaction as moderate. Demeclocycline and Magnesium 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. Magnesium forms insoluble chelates with tetracyclines such as demeclocycline in the gut, reducing absorption. This may cause antibiotic treatment failure.
How serious is the interaction between Demeclocycline and Magnesium?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Give demeclocycline at least 2 hours before or 4 hours after oral magnesium products. Alternatively, use a non-chelating antibiotic.
What other medicines interact with Magnesium?
MediHelp also lists interactions of Magnesium with, for example, Ciprofloxacin, Pancuronium, Rocuronium. The full list is on the Magnesium page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
