Is Grapefruit Juice Safe with Verapamil?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Avoid grapefruit and grapefruit juice. Monitor for signs of toxicity including slow heart rate, dizziness, or swelling. Notify your doctor if these occur.
Why this interaction occurs
Grapefruit juice inhibits CYP3A4, the primary enzyme responsible for verapamil metabolism. This increases verapamil plasma levels, potentiating its negative chronotropic and dromotropic effects, potentially causing bradycardia or AV block.
Evidence
Evidence level: strong.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 41,693 reports mentioning Verapamil. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Verapamil + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All Grapefruit Juice interactions → · All Verapamil interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.