Drug interactions
Doxycycline + Magnesium oxide
Severity: Moderate
Doxycycline and Magnesium oxide: 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 oxide, used as a supplement or antacid, binds doxycycline in the gut and reduces its absorption, risking subtherapeutic antibiotic levels.
What this interaction means in plain words
Doxycycline and Magnesium oxide 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.
Doxycycline belongs to Anti Bacterial; Magnesium oxide belongs to Gastrointestinal Tract.
Why it happens
Chelation of doxycycline by magnesium cations, plus raised gastric pH, reduces absorption.
What to do
Give doxycycline at least 2 hours before or 4 hours after magnesium oxide. Monitor clinical response to the 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?
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Other interactions of Doxycycline
- Acitretin + Doxycycline Contraindicated
- Aminolevulinic acid + Doxycycline Major
- Cholera vaccine + Doxycycline Major
- Doxycycline + Isotretinoin Major
- Doxycycline + Methoxyflurane Major
- Doxycycline + Microbiota Major
Other interactions of Magnesium oxide
- Chloroquine + Magnesium oxide Moderate
- Ciprofloxacin + Magnesium oxide Moderate
- Dolutegravir + Magnesium oxide Moderate
- Eltrombopag + Magnesium oxide Moderate
- Gemifloxacin + Magnesium oxide Moderate
- Gentamicin + Magnesium oxide Moderate
Frequently asked questions
Can I take Doxycycline with Magnesium oxide?
MediHelp rates the interaction as moderate. Doxycycline and Magnesium oxide 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 oxide, used as a supplement or antacid, binds doxycycline in the gut and reduces its absorption, risking subtherapeutic antibiotic levels.
How serious is the interaction between Doxycycline and Magnesium oxide?
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 doxycycline at least 2 hours before or 4 hours after magnesium oxide. Monitor clinical response to the antibiotic.
What other medicines interact with Doxycycline?
MediHelp also lists interactions of Doxycycline with, for example, Acitretin, Aminolevulinic acid, Cholera vaccine. The full list is on the Doxycycline page.
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