Drug interactions
Demeclocycline + Magnesium sulphate
Severity: Moderate
Demeclocycline and Magnesium sulphate: 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
Oral magnesium binds demeclocycline in the gut to form poorly absorbed complexes. This can substantially reduce tetracycline levels and cause treatment failure. The interaction applies to oral magnesium, not intravenous administration.
What this interaction means in plain words
Demeclocycline and Magnesium sulphate 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 magnesium cations in the gastrointestinal tract decreases absorption.
What to do
Give demeclocycline at least 2 hours before or 4 to 6 hours after oral magnesium preparations. Alternatively use a non-chelating antibiotic or a non-magnesium laxative or antacid.
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 Magnesium sulphate
- Amikacin + Magnesium sulphate Moderate
- Amphotericin b deoxycholate + Magnesium sulphate Moderate
- Atracurium + Magnesium sulphate Moderate
- Baloxavir marboxil + Magnesium sulphate Moderate
- Ciprofloxacin + Magnesium sulphate Moderate
- Cisatracurium + Magnesium sulphate Moderate
Frequently asked questions
Can I take Demeclocycline with Magnesium sulphate?
MediHelp rates the interaction as moderate. Demeclocycline and Magnesium sulphate 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. Oral magnesium binds demeclocycline in the gut to form poorly absorbed complexes. This can substantially reduce tetracycline levels and cause treatment failure. The interaction applies to oral magnesium, not intravenous administration.
How serious is the interaction between Demeclocycline and Magnesium sulphate?
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 to 6 hours after oral magnesium preparations. Alternatively use a non-chelating antibiotic or a non-magnesium laxative or antacid.
What other medicines interact with Magnesium sulphate?
MediHelp also lists interactions of Magnesium sulphate with, for example, Amikacin, Amphotericin b deoxycholate, Atracurium. The full list is on the Magnesium sulphate page.
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