Background

Grapefruit (Citrus paradisi) is a citrus fruit. It has been used for weight loss. It has also been used for other conditions, but with limited evidence.

Grapefruit is a source of vitamin C, fiber, potassium, pectin, and other nutrients. People use the fruit, oil from the peel, and extracts as medicine. Drug interactions with grapefruit juice are well documented. Before adding it to your diet, check with your healthcare provider if you take medications.

People commonly take grapefruit by mouth for weight loss, asthma, high cholesterol, cancer, and many other conditions, but there is no good scientific evidence to support these uses.

Safety Safety definitions

When taken by mouth: Grapefruit is commonly consumed as a food or juice. Grapefruit products are possibly safe when taken by mouth as a medicine. But it is possibly unsafe for postmenopausal adults to take grapefruit in large amounts.

If you take any medications, check with your healthcare provider before adding grapefruit to your diet or using it as a medicine. Grapefruit interacts with a long list of medications.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if grapefruit is safe to use when pregnant or breast-feeding. Stay on the safe side and stick to normal food amounts.

A heart muscle disorder (cardiomyopathy): Drinking grapefruit juice might increase the risk for abnormal heart rhythm. People with this condition should consume grapefruit juice in moderation.

Hormone sensitive cancers and conditions: Consuming large amounts of grapefruit might increase hormone levels and therefore increase the risk of hormone sensitive conditions. People with hormone sensitive conditions should avoid grapefruit.

Irregular heartbeat: Eating large amounts of grapefruit or drinking grapefruit juice might worsen irregular heartbeat. Don't use grapefruit if you have this condition.

Postmenopausal adults: Postmenopausal adults should avoid consuming large amounts of grapefruit. It's been linked with an increased risk of breast cancer in these patients.

Effectiveness

Dosing & administration

Grapefruit and grapefruit juice are commonly consumed as part of the diet. The pectin, extracts, and freeze-dried whole fruit are also used as medicine. Speak with a healthcare provider to find out what dose might be best for a specific condition.

Keep in mind that drug interactions with grapefruit juice are well documented. Before adding it to your diet, check with your healthcare provider if you take medications.

Interactions with pharmaceuticals

Acebutolol (Sectral)

Interaction Rating=Minor Be watchful with this combination.

Acebutolol is moved by pumps in cells in the body. Grapefruit might change how these pumps work, making this medication less effective. Separate taking this medication from consuming grapefruit by at least 4 hours.

Aliskiren (Tekturna, Rasilez)

Interaction Rating=Moderate Be cautious with this combination.

Aliskiren is moved by pumps in cells in the body. Grapefruit might change how these pumps work, making this medication less effective. Separate taking this medication from consuming grapefruit by at least 4 hours.

Amiodarone (Cordarone)

Interaction Rating=Major Do not take this combination.

Grapefruit juice can increase how much amiodarone the body absorbs. Drinking grapefruit juice might increase the effects and side effects of amiodarone. Avoid drinking grapefruit juice if you are taking amiodarone.

Amprenavir (Agenerase)

Interaction Rating=Minor Be watchful with this combination.

Grapefruit might slightly decrease how much amprenavir is absorbed by the body. But this interaction is probably not a major concern.

Artemether (Artenam, Paluther)

Interaction Rating=Major Do not take this combination.

Grapefruit juice can decrease how quickly the body breaks down artemether. Drinking grapefruit juice while taking artemether might increase the effects and side effects of artemether. Do not drink grapefruit juice if you are taking artemether.

Budesonide (Entocort, UCERIS)

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit might decease how quickly the body gets rid of budesonide. Drinking grapefruit while taking budesonide might increase the side effects of budesonide.

Buspirone (BuSpar)

Interaction Rating=Major Do not take this combination.

Grapefruit juice might increase how much buspirone the body absorbs. Drinking grapefruit juice while taking buspirone might increase the effects and side effects of buspirone.

Caffeine

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit might decease how quickly the body gets rid of caffeine. Drinking grapefruit juice while taking caffeine might increase the side effects of caffeine including jitteriness, headache, and a fast heartbeat.

Carbamazepine (Tegretol)

Interaction Rating=Major Do not take this combination.

Grapefruit juice might increase how much carbamazepine the body absorbs. Drinking grapefruit juice while taking carbamazepine might increase the effects and side effects of carbamazepine.

Carvedilol (Coreg)

Interaction Rating=Major Do not take this combination.

Grapefruit juice seems to decrease how quickly the body breaks down carvedilol. Drinking grapefruit juice while taking carvedilol might increase the effects and side effects of carvedilol.

Celiprolol (Celicard)

Interaction Rating=Major Do not take this combination.

Grapefruit appears to decrease how much celiprolol is absorbed by the body. This might decrease the effects of celiprolol. Separate administration of celiprolol and consumption of grapefruit by at least 4 hours.

Cisapride (Propulsid)

Interaction Rating=Major Do not take this combination.

Grapefruit juice might decrease how quickly the body gets rid of cisapride. Drinking grapefruit juice while taking cisapride might increase the effects and side effects of cisapride.

Clomipramine (Anafranil)

Interaction Rating=Major Do not take this combination.

Grapefruit juice might decrease how quickly the body gets rid of clomipramine. Taking grapefruit juice along with clomipramine might increase the effects and side effects of clomipramine.

Clopidogrel (Plavix)

Interaction Rating=Major Do not take this combination.

Clopidogrel needs to be activated by the body to work. Grapefruit appears to decrease how much clopidogrel is activated by the body. This might reduce the effects of clopidogrel.

Colchicine

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit might decrease how quickly the body gets rid of colchicine. Taking grapefruit juice along with colchicine might increase the effects and side effects of colchicine.

Cyclosporine (Neoral, Sandimmune)

Interaction Rating=Major Do not take this combination.

Grapefruit might increase how much cyclosporine the body absorbs. Drinking grapefruit juice while taking cyclosporine might increase the side effects of cyclosporine.

Dextromethorphan (Robitussin DM, and others)

Interaction Rating=Major Do not take this combination.

Grapefruit might decrease how quickly the body gets rid of dextromethorphan. Drinking grapefruit juice while taking dextromethorphan might increase the effects and side effects of dextromethorphan.

Erythromycin

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit can decrease how quickly the body gets rid of erythromycin. Taking grapefruit juice along with erythromycin might increase the effects and side effects of erythromycin.

Estrogens

Interaction Rating=Major Do not take this combination.

Grapefruit seems to decrease how quickly the body breaks down estrogens and increase how much estrogen the body absorbs. Eating grapefruit or drinking grapefruit juice while taking estrogens might increase estrogen levels and side effects associated with estrogen.

Etoposide (VePesid)

Interaction Rating=Major Do not take this combination.

Grapefruit might decrease how much etoposide the body absorbs. Drinking grapefruit juice while taking etoposide might decrease the effects of etoposide. Separate taking this medication from consuming grapefruit by at least 4 hours.

Fexofenadine (Allegra)

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit might decrease how much fexofenadine the body absorbs. Drinking grapefruit juice while taking fexofenadine might decrease the effects of fexofenadine. Separate taking this medication from consuming grapefruit by at least 4 hours.

Fluvoxamine (Luvox)

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit juice can increase how much fluvoxamine the body absorbs. Drinking grapefruit juice while taking fluvoxamine might increase the effects and side effects of fluvoxamine.

Halofantrine

Interaction Rating=Major Do not take this combination.

Grapefruit juice seems to decrease how quickly the body breaks down halofantrine. Drinking grapefruit juice while taking halofantrine might increase halofantrine levels and side effects associated with halofantrine, including abnormal heartbeat.

Itraconazole (Sporanox)

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit juice might change how much itraconazole the body absorbs. But there isn't enough information to know if this interaction is a major concern.

Levothyroxine (Synthroid, others)

Interaction Rating=Moderate Be cautious with this combination.

Levothyroxine is moved by pumps in cells in the body. Grapefruit might change how these pumps work, making this medication less effective. Separate taking this medication from consuming grapefruit by at least 4 hours.

Losartan (Cozaar)

Interaction Rating=Moderate Be cautious with this combination.

The liver activates losartan to make it work. Grapefruit juice might decrease how quickly the body activates losartan. Drinking grapefruit juice while taking losartan might decrease the effects of losartan.

Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)

Interaction Rating=Moderate Be cautious with this combination.

Some medications are changed and broken down by the liver. Grapefruit might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

Medications changed by the liver (Cytochrome P450 2C19 (CYP2C19) substrates)

Interaction Rating=Moderate Be cautious with this combination.

Some medications are changed and broken down by the liver. Grapefruit might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates)

Interaction Rating=Moderate Be cautious with this combination.

Some medications are changed and broken down by the liver. Grapefruit might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)

Interaction Rating=Major Do not take this combination.

Some medications are changed and broken down by the liver. Grapefruit might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

Medications for high blood pressure (Calcium channel blockers)

Interaction Rating=Major Do not take this combination.

Grapefruit juice might increase how much medication for high blood pressure the body absorbs. Drinking grapefruit juice while taking some medications for high blood pressure might cause your blood pressure to go too low.

Medications moved by pumps in cells (Organic anion-transporting polypeptide substrates)

Interaction Rating=Major Do not take this combination.

Some medications are moved in and out of cells by pumps. Grapefruit might change how these pumps work and change how much medication stays in the body. In some cases, this might change the effects and side effects of a medication.

Medications moved by pumps in cells (P-glycoprotein substrates)

Interaction Rating=Minor Be watchful with this combination.

Some medications are moved in and out of cells by pumps. Grapefruit might change how these pumps work and change how much medication stays in the body. In some cases, this might change the effects and side effects of a medication.

Medications that can cause an irregular heartbeat (QT interval-prolonging drugs)

Interaction Rating=Major Do not take this combination.

Grapefruit might affect electrical currents in the heart. This can increase the risk of having an irregular heartbeat. Some medications can have this same effect. Taking grapefruit with these medications might increase the risk for a serious heart issue.

Medications used for lowering cholesterol (Statins)

Interaction Rating=Major Do not take this combination.

Grapefruit juice might decrease how quickly the body breaks down some "statin" medications. Drinking grapefruit juice while taking certain "statins" might increase the effects and side effects of these medications.

Methadone (Dolophine)

Interaction Rating=Major Do not take this combination.

Grapefruit juice can decrease how quickly the body breaks down methadone. Drinking grapefruit juice while taking methadone can increase the effects and side effects of methadone.

Methylprednisolone

Interaction Rating=Major Do not take this combination.

Grapefruit juice can decrease how quickly the body gets rid of methylprednisolone. Drinking grapefruit juice while taking methylprednisolone might increase the effects and side effects of methylprednisolone.

Nadolol (Corgard)

Interaction Rating=Moderate Be cautious with this combination.

Nadolol is moved by pumps in cells in the body. Grapefruit might change how these pumps work. But it's not clear if this is a big concern. Until more is known, follow any instructions on the nadolol label related to intake of grapefruit.

Nilotinib (Tasigna)

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit juice can increase how much nilotinib the body absorbs. Drinking grapefruit juice while taking nilotinib might increase the effects and side effects of nilotinib.

Oxycodone (Oxycontin)

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit juice can decrease how quickly the body breaks down oxycodone. Drinking grapefruit juice while taking oxycodone might increase the side effects of oxycodone.

Pitavastatin (Livalo)

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit juice might decrease how quickly the body breaks down pitavastatin. Drinking grapefruit juice while taking pitavastatin might increase the effects and side effects of pitavastatin.

Prasugrel (Effient)

Interaction Rating=Moderate Be cautious with this combination.

Prasugrel needs to be activated by the body to work. Grapefruit appears to decrease how much prasugrel is activated by the body. This might reduce the effects of prasugrel.

Praziquantel (Biltricide)

Interaction Rating=Major Do not take this combination.

Grapefruit juice can decrease how quickly the body breaks down praziquantel. Drinking grapefruit juice while taking praziquantel might increase the effects and side effects of praziquantel.

Primaquine

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit juice can increase how much primaquine is available in the body. But it's not clear if this is a big concern or what effects it might have.

Quetiapine (Seroquel)

Interaction Rating=Major Do not take this combination.

Grapefruit juice might decrease how fast the body gets rid of quetiapine. Drinking grapefruit juice while taking quetiapine might increase the chance of side effects from quetiapine.

Quinidine

Interaction Rating=Major Do not take this combination.

Grapefruit juice might decrease how fast the body gets rid of quinidine. Drinking grapefruit juice while taking quinidine might increase the chance of side effects from quinidine.

Saquinavir (Fortovase, Invirase)

Interaction Rating=Moderate Be cautious with this combination.

Drinking grapefruit juice can increase how much saquinavir the body absorbs. Drinking grapefruit juice while taking saquinavir might increase the effects and side effects of saquinavir.

Scopolamine (Transderm Scop)

Interaction Rating=Major Do not take this combination.

Grapefruit juice can decrease how fast the body breaks down scopolamine. Drinking grapefruit juice while taking scopolamine might increase the effects and side effects of scopolamine.

Sedative medications (Benzodiazepines)

Interaction Rating=Major Do not take this combination.

Sedative medications can cause sleepiness and drowsiness. Drinking grapefruit juice while taking some sedative medications can increase the effects and side effects of some sedative medications.

Sertraline (Zoloft)

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit can decrease how quickly the body breaks down sertraline. Drinking grapefruit juice while taking sertraline can increase the effects and side effects of sertraline.

Sildenafil (Viagra)

Interaction Rating=Major Do not take this combination.

Grapefruit can decrease how quickly the body breaks down sildenafil. Drinking grapefruit juice while taking sildenafil can increase the effects and side effects of sildenafil.

Sunitinib (Sutent)

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit might decrease how quickly the body breaks down sunitinib. Drinking grapefruit juice while taking sunitinib might increase the effects and side effects of sunitinib. Until more is known, follow any instructions on the sunitinib label related to intake of grapefruit.

Tacrolimus (Prograf)

Interaction Rating=Major Do not take this combination.

Grapefruit can decrease how quickly the body breaks down tacrolimus. Eating grapefruit or drinking grapefruit juice while taking tacrolimus can increase the effects and side effects of tacrolimus. Avoid eating grapefruit or drinking grapefruit juice if you are taking tacrolimus.

Tadalafil (Cialis)

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit juice might decrease how quickly the body breaks down tadalafil. Drinking grapefruit juice while taking tadalafil might increase the effects and side effects of tadalafil.

Talinolol

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit juice can reduce how much talinolol is available in the body. Drinking grapefruit juice with talinolol might reduce the effects of talinolol.

Terfenadine (Seldane)

Interaction Rating=Major Do not take this combination.

Grapefruit can increase how much terfenadine the body absorbs. Drinking grapefruit juice while taking terfenadine might increase the effects and side effects of terfenadine.

Theophylline

Interaction Rating=Moderate Be cautious with this combination.

Drinking grapefruit juice might decrease the effects of theophylline. There's not enough information to know if this is a big concern.

Ticagrelor (Brilinta)

Interaction Rating=Major Do not take this combination.

Grapefruit can decrease how quickly the body breaks down ticagrelor. Drinking grapefruit juice while taking ticagrelor can increase the effects and side effects of ticagrelor.

Tolvaptan (Samsca)

Interaction Rating=Moderate Be cautious with this combination.

Grapefruit can decrease how quickly the body breaks down tolvaptan. Drinking grapefruit juice while taking tolvaptan can increase the effects and side effects of tolvaptan.

Warfarin (Coumadin)

Interaction Rating=Moderate Be cautious with this combination.

Warfarin is used to slow blood clotting. Drinking grapefruit juice might increase the effects of warfarin and increase the chances of bruising and bleeding. Be sure to have your blood checked regularly. The dose of your warfarin might need to be changed.

Interactions with herbs & supplements

Herbs and supplements that might cause an irregular heartbeat (QT interval-prolonging products): Grapefruit might affect electrical currents in the heart. This can increase the risk of having an irregular heartbeat. Taking grapefruit with other supplements with similar effects might increase the risk for a serious heart issue. Examples of supplements with this effect include bitter orange, ephedra, iboga, and Panax ginseng.
Licorice: Drinking grapefruit juice when taking licorice might increase licorice's ability to lower potassium levels.
Red yeast: Grapefruit (juice or fruit) changes the way the body processes red yeast. Grapefruit can increase the amount of a certain chemical, called lovastatin, from red yeast in the blood.
Thunder god vine: Thunder god vine contains triptolide. Grapefruit can decrease how quickly the body breaks down triptolide. Drinking grapefruit juice while taking thunder god vine might increase the effects and side effects of thunder god vine.

Interactions with foods

People who have a heart rhythm disorder (long QT syndrome, for example) should avoid taking grapefruit and tonic water together. That combination might worsen some heart conditions. Also, don't drink red wine and grapefruit juice together if you take any medications. This combination can make grapefruit juice interact with medications even more.