🟡

Calcium × Tetracyclines

MODERATE INTERACTION — Well-Established Evidence

⚠️ Mechanism

Calcium chelates tetracycline antibiotics, forming insoluble complexes that reduce absorption.

📋 Effect

Reduced tetracycline absorption and efficacy

💊 Management

Separate doses by at least 2 hours before or 4 hours after tetracycline.

Plain Language Summary

This combination requires caution because calcium can bind to tetracycline antibiotics, which prevents your body from absorbing the medicine properly. This interaction may make the antibiotic less effective at treating an infection.

Source

FDA tetracycline labeling; Neuvonen PJ. Drugs 1976

Supporting Research

First-line drugs for hypertension PMID:29667175 DOI:10.1002/14651858.CD001841.pub3 2018
Beta-blockers for hypertension PMID:28107561 DOI:10.1002/14651858.CD002003.pub5 2017
Calcium channel blockers versus other classes of drugs for hypertension PMID:34657281 DOI:10.1002/14651858.CD003654.pub5 2021
Effect of early treatment with anti-hypertensive drugs on short and long-term mortality in patients with an acute cardiovascular event PMID:19821384 DOI:10.1002/14651858.CD006743.pub2 2009
Phlebotonics for venous insufficiency PMID:27048768 DOI:10.1002/14651858.CD003229.pub3 2016
Calcium channel blockers versus other classes of drugs for hypertension PMID:35000192 DOI:10.1002/14651858.CD003654.pub6 2022
Calcium supplementation for prevention of primary hypertension PMID:34693985 DOI:10.1002/14651858.CD010037.pub3 2021
Calcium supplementation for prevention of primary hypertension PMID:35014026 DOI:10.1002/14651858.CD010037.pub4 2022
Medical Disclaimer: This interaction record is for informational and educational purposes only and does not constitute medical advice. Drug-supplement interactions can be dangerous. Always consult your healthcare provider or pharmacist before combining any supplement with prescription medications. Do not stop or change any medication without professional guidance.