Drug interactions
Calcium chloride + Doxycycline
Severity: Moderate
Calcium chloride and Doxycycline: 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 calcium chloride can chelate doxycycline in the gut and lower its absorption, risking subtherapeutic antibiotic levels. Intravenous calcium chloride does not interact this way.
What this interaction means in plain words
Calcium chloride and Doxycycline 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 doxycycline by calcium cations in the gastrointestinal tract reduces absorption.
What to do
If both are taken orally, separate doxycycline from calcium by at least 2 hours before or 4 hours after. No adjustment is needed for intravenous calcium.
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
Frequently asked questions
Can I take Calcium chloride with Doxycycline?
MediHelp rates the interaction as moderate. Calcium chloride and Doxycycline 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 calcium chloride can chelate doxycycline in the gut and lower its absorption, risking subtherapeutic antibiotic levels. Intravenous calcium chloride does not interact this way.
How serious is the interaction between Calcium chloride and Doxycycline?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: If both are taken orally, separate doxycycline from calcium by at least 2 hours before or 4 hours after. No adjustment is needed for intravenous calcium.
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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