PHARMACOLOGICAL EFFECTS OF COMMON MEDICATIONS WITH GRAPEFRUIT JUICE
 

Grapefruit is a healthy addition to a well-balanced diet. However, the fruit or juice has been shown to affect the metabolism of many medications, increasing the risk of toxicity and adverse events. Characteristics of oral medications that may interact with grapefruit include extensive metabolism through the intestinal cytochrome P450 3A4 (CYP3A4) system, low bioavailability, and a narrow therapeutic index. Grapefruit juice interacts through the intestinal CYP3A4 system and can inhibit the concentration for 24–72 hours.1 This list is based on manufacturer's prescribing information and is not a complete list of medications that may interact with grapefruit. Caution should be taken by both patient and physician and monitor adverse reactions when taking medications that may interact with grapefruit or juice.

BrandGenericClinical Implications of Co-administration with Grapefruit or Grapefruit Juice
ALKALOID
ColcryscolchicineIncreases the risk of colchicine-induced toxic effects; significant increase in colchicine plasma concentration is anticipated. Grapefruit and grapefruit juice should not be consumed during colchicine treatment.
ANTIARRHYTHMICS
CordaroneamiodaroneInhibits CYP3A4-mediated metabolism of oral amiodarone resulting in increase plasma levels of amiodarone. Avoid co-administration.
MultaqdronedaroneModerate inhibitor of CYP3A, results in a 3-fold increase in dronedarone exposure and a 2.5-fold increase in Cmax. Avoid co-administration.
TikosyndofetilideInhibitor of the CYP3A4 isoenzyme, thus could increase systemic dofetilide exposure. If co-administration is necessary, use with caution.
ANTIHELMINTHIC
Biltricidepraziquantel 1.6-fold increase in the Cmax and a 1.9-fold increase in the AUC of praziquantel.
ANTIPSYCHOTIC
OrappimozideInhibits CYP3A4-mediated metabolism of pimozide. Avoid co-administration.
CALCIUM CHANNEL BLOCKERS
Plendilfelodipine2-fold increase in felodipine AUC and Cmax. Avoid co-administration prior to and during treatment.
Procardianifedipine2-fold increase in nifedipine AUC and Cmax with no change in half-life. Avoid co-administration.
Sularnisoldipine3-fold increase in nisoldipine Cmax and 2-fold increase in nisoldipine AUC. Avoid co-administration before and after dosing
Verelan verapamilMay significantly increase concentrations of verapamil. Increased S- and R-verapamil AUC0-12 by 36% and 28%, respectively. Steady state Cmax and Cmin of S-verapamil increased by 57% and 16.7%, respectively compared to control. Cmax and Cmin of R-verapamil increased by 40% and 13%, respectively.
CHOLESTEROL-LOWERING MEDICATIONS
LipitoratorvastatinInhibits CYP3A4 and can increase plasma concentrations of atorvastatin, especially with excessive grapefruit juice consumption (>1.2 liters per day).
MevacorlovastatinInhibits CYP3A4 and can increase plasma concentrations of lovastatin. Avoid large quantities of grapefruit juice (>1 quart daily).
ZocorsimvastatinInhibits CYP3A4 and can increase plasma concentrations of simvastatin and may increase risk of myopathy. Avoid large quantities of grapefruit juice (>1 quart daily
CYSTIC FIBROSIS THERAPY
KalydecoivacaftorCo-administration may increase exposure of ivacaftor. Grapefruit or Seville oranges should be avoided during treatment.
ERGOT ALKALOIDS
D.H.E. 45dihydroergotamine mesylateA potential risk for serious toxicity (including vasospasm) exists.
 ergotamine tartrate + caffeineA potential risk for serious toxicity (including vasospasm) exists.
H1-RECEPTOR ANTAGONIST
AllegrafexofenadineMay reduce bioavailability and exposure of fexofenadine. In a bioequivalence study, the bioavailability of fexofenadine was reduced by 36%. Take with water.
HYPONATREMIA THERAPY
SamscatolvaptanCo-administration results in a 1.8-fold increase in exposure to tolvaptan.
IMMUNOSUPPRESSANTS
NeoralcyclosporineAffects metabolism and increases blood concentrations of cyclosporine. Avoid co-administration.
PrograftacrolimusAffects CYP3A-mediated metabolism and should be avoided.
RapamunesirolimusReduces CYP3A4-mediated drug metabolism and must not be taken with or used for dilution of sirolimus.
ToriseltemsirolimusMay increase plasma concentrations of sirolimus, a major metabolite of temsirolimus, and should be avoided.
ZortresseverolimusInhibits CYP3A4 and P-gp activity and should therefore be avoided with concomitant use of everolimus and cyclosporine.
INTERMITTENT CLAUDICATION THERAPY
PletalcilostazolIncrease in the Cmax of cilostazol by ∼50%, but has no effect on AUC.
MYELOFIBROSIS THERAPY
JakafiruxolitinibThe recommended starting dose of ruloxitinib is 10mg twice daily for patients with a platelet count ≥100 × 109/L. Concurrent administration of should be avoided in patients with platelet counts <100 × 109/L.
ONCOLOGY AGENTS
AfinitoreverolimusMay increase exposures of everolimus and should be avoided.
InlytaaxitinibMay increase plasma concentrations of axitinib and should be avoided.
IxempraixabepiloneMay increase plasma concentrations of ixabepilone and should be avoided.
SpryceldasatinibMay increase plasma concentrations of dasatinib and should be avoided.
SutentsunitinibMay increase plasma concentrations of sunitinib and should be avoided.
TasignanilotinibMay increase plasma concentrations of nilotinib and should be avoided.
TykerblapatanibMay increase plasma concentrations of lapatinib and should be avoided.
VotrientpazopanibMay increase plasma concentrations of pazopanib and should be avoided.
XalkoricrizotinibMay increase plasma concentrations of crizotinib and should be avoided.
OPIOID
FentorafentanylMay result in a potentially dangerous increase in fentanyl plasma concentrations, which could increase or prolong adverse drug effects and may cause potentially fatal respiratory depression.
PHOSPHODIESTERASE TYPE 5 INHIBITORS
CialistadalafilLikely increase of tadalafil exposure.
StaxynvardenafilDo not use, as the systemic concentration of vardenafil is increased.
PSYCHOTROPIC AGENTS
BuSparbuspirone4.3 fold increase in Cmax; 9.2 fold increase in AUC. Avoid drinking large amounts (200mL double-strength three times daily) of grapefruit juice.
HalciontriazolamIncreases the Cmax of triazolam by 25%, increases AUC by 48%, and increases half-life by 18%. Use with caution.
STEROID
Entocort ECbudesonideAfter extensive intake of grapefruit juice, the systemic exposure for oral budesonide increased about two times. Ingestion of grapefruit or grapefruit juice should be avoided.
NOTES

1 Stump AL, Mayo T, Blum A. Management of Grapefruit-Drug Interactions. Am Fam Physician. 2006 Aug 15;74(4):605–608.

AUC = area under the curve; Cmax = max concentration