drug-food interaction
5 interactions related to drug-food interaction
itraconazole + grapefruit
Grapefruit juice can reduce the absorption of itraconazole capsules in healthy-volunteer studies, lowering antifungal blood levels. The likely mechanism is a rise in gastric pH that interferes with the capsule's dissolution, which outweighs grapefruit's usual CYP3A4-inhibiting effect.
fluconazole + grapefruit
Fluconazole is a moderate inhibitor of the liver enzyme CYP3A4, and grapefruit irreversibly inhibits intestinal CYP3A4. Their effects overlap on the same enzyme. On their own the pair rarely causes a problem, but together they can further slow the clearance of a third medication that also depends on CYP3A4, allowing its blood levels to rise.
amlodipine + grapefruit
Amlodipine is a CYP3A4 substrate, but unlike other dihydropyridine calcium channel blockers such as felodipine and nisoldipine, its high oral bioavailability and slow elimination mean grapefruit juice does not meaningfully alter its pharmacokinetics in controlled trials. Some product labels and consumer references still list a theoretical interaction, but the clinical signal at ordinary dietary intakes is small to negligible.
diltiazem + grapefruit
Grapefruit inhibits intestinal CYP3A4, modestly and unpredictably increasing systemic exposure to diltiazem.
amiodarone + grapefruit
Grapefruit and grapefruit juice inhibit intestinal CYP3A4, the enzyme that metabolizes oral amiodarone. This raises amiodarone blood levels and largely shuts down production of its active metabolite, N-desethylamiodarone. The FDA-approved Pacerone label explicitly states grapefruit juice should not be consumed during oral amiodarone treatment.