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Cranberry × Calcium Channel Blockers

MODERATE INTERACTION

⚠️ Mechanism

Cranberry is a weak inhibitor of CYP3A4, which decreases metabolism of CYP3A4 substrates, potentially increasing their plasma concentrations and risk of adverse effects.

📋 Effect

Increased plasma levels of nifedipine (calcium-channel-blockers), potentially leading to toxicity or enhanced adverse effects.

💊 Management

Monitor for increased adverse effects of nifedipine. Dose reduction may be necessary. Consider alternative supplement or consult healthcare provider.

Plain Language Summary

This combination may be moderately risky because cranberry can prevent your body from breaking down certain blood pressure medications properly. This can cause the medication levels to rise in your bloodstream, which may increase your risk of experiencing side effects.

Source

Flockhart CYP450 Table (drug-interactions.medicine.iu.edu)

Supporting Research

Study of Oral Anthocyanins on Insulin Resistance 2010
The Effect of Cranberry Extract Supplementation on Cardiovascular Risk Factors in Obese, Insulin Resistant Humans 2014
Adverse Event Profile: Cranberry 0
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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.