II. Metabolism
- Decreases intestinal Cytochrome P450 3A4
- Increases level of drugs metabolized by CYP 3A4
- Drugs most affected are those with low oral absorption
- Small Grapefruit exposure can lead to Clinically SignificantDrug Interaction
- Single Grapefruit
- One cup of Grapefruit juice
- Effect onset: Within 4 hours of Grapefruit intake
- Effect duration: May persist 24-72 hours
- Grapefruit permanently binds and inactivates CYP 3A4 enzymes
- Enzymes replaced every 48-72 hours
III. Drug Interactions: Increased serum concentrations
-
Antiarrhythmics
- Agents affected
- Alternative agents not affected by Grapefruit
-
Calcium Channel Blockers
- Agents affected
- Alternative agents not affected by Grapefruit
-
Statins
- Agents affected
- Alternative agents not affected by Grapefruit
-
Immunosuppressants
- Agents affected
-
Protease Inhibitors
- Agents affected
- Alternative agents not affected by Grapefruit
- Miscellaneous agents
- Versed
- Estrogens
- Caffeine
- Ticagrelor (Brilanta)
- Increased Gastrointestinal Bleeding risk
- Dronedarone (Multaq)
- Increased Arrhythmia risk
- Eplerenone (Inspra)
- Increased Hyperkalemia risk
- Terfenadine (Seldane)
- Not available in United States since 1998
- Can aggravate QT Prolongation
IV. References
- (1995) Medical Letter 37(955):73
- (2013) Prescr Lett 20(1): 1
- Stump (2006) Am Fam Physician 605-11 [PubMed]
- Dahan (2004) Eur J Clin Nutr 58:1-9 [PubMed]
- Kane (2000) Mayo Clin Proc 75:933-42 [PubMed]
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Definition (MSH) | A plant species of the genus CITRUS, family RUTACEAE that produces the familiar grapefruit. There is evidence that grapefruit inhibits CYTOCHROME P-450 CYP3A4, resulting in delayed metabolism and higher blood levels of a variety of drugs. |
Definition (ALT) | Grapefruit. |
Concepts | Plant (T002) |
MSH | D032083 |
Swedish | Grapefrukt |
Czech | Citrus paradisi |
Finnish | Citrus paradisi |
Russian | GREIPFRUT, ГРЕЙПФРУТ |
Japanese | グレープフルーツ |
English | grapefruit, grapefruits, Citrus paradisi, Citrus x paradisi Macfad., Citrus x paradisi, citrus paradisi, Citrus sinensis x Citrus grandis, Citrus sinensis x Citrus maxima |
Polish | Grejpfrut |
Norwegian | Citrus paradisi |
Portuguese | Toronja, Citrus paradisi |
French | Citrus paradisi |
German | Citrus paradisi |
Italian | Citrus paradisi |
Dutch | Citrus paradisi |
Spanish | Citrus paradisi |