Food and medicine interaction
Grapefruit and grapefruit juice and some calcium channel blockers for blood pressure, such as felodipine and nifedipine
EstablishedEvidence level: established. Shown in drug labeling or in controlled studies in people.
Last reviewed
What can happen
In the 1991 study that first described the interaction, felodipine taken with grapefruit juice reached on average 284% of the blood level reached with water, with lower blood pressure, a faster heart rate and more side effects. Orange juice had no such effect.
- Why it happens
- Grapefruit inhibits the CYP3A4 enzyme in the gut wall, so more of the drug is absorbed.
- At ordinary food amounts
- Yes. The original study used ordinary servings of juice, and FDA lists nifedipine among drugs whose labels warn about grapefruit.
What to do
Check with your pharmacist before having grapefruit with any blood pressure medicine. Do not change your dose yourself; if grapefruit matters to you, your prescriber may be able to pick a drug it does not affect.
Never stop or change a prescribed medicine without talking to the prescriber.
Common questions
Can I have grapefruit and grapefruit juice while taking calcium channel blockers?
Check with your pharmacist before having grapefruit with any blood pressure medicine. Do not change your dose yourself; if grapefruit matters to you, your prescriber may be able to pick a drug it does not affect. Yes. The original study used ordinary servings of juice, and FDA lists nifedipine among drugs whose labels warn about grapefruit.
Sources
Related
- RemedyGrapefruit: the full evidence pageA healthy fruit with one serious catch: it changes how the body handles certain medicines. It is the best-documented food-drug interaction there is. The fat-burning claims are not supported.
- Interaction · EstablishedGrapefruit and grapefruit juice and some statins, such as simvastatin (Zocor) and atorvastatin (Lipitor)