What Really Happens If You Eat Grapefruit With Your Medication?

Sure, starting off your day with a halved grapefruit or a glass of its tart juice can be a healthy choice—lots of vitamin C and potassium—but if you take certain drugs, it might actually be just the opposite.

“Grapefruit can affect the functioning of many different medications,” Emily Van Eck, MS, RDN, an Austin-based dietitian nutritionist, tells SELF. Specifically, it can alter the amount that reaches your system, exacerbating or mitigating the intended effects, Van Eck says. So yes, if you’ve ever been told to avoid grapefruit while taking certain meds, know that this advice is legit.

But does it apply to all meds, or are only some drugs at risk? And what about grapefruit juice versus chunks of the actual fruit? Below, we break down everything you need to know about grapefruit and medication interactions so you can stay safe.

How does grapefruit interact with medication in the first place?

In most cases, grapefruit interferes with meds by messing with an enzyme in your intestines called CYP3A4, which plays a role in metabolizing certain drugs. Under normal circumstances, CYP3A4 reduces their absorption and makes it harder for them to enter your bloodstream, but when you eat or drink grapefruit, compounds known as furanocoumarins bind to the enzyme, keeping it from doing its job. The result? The amount of the med that is absorbed and then released into your bloodstream “actually increases,” Yi Guo, PharmD, an associate professor at the Albert Einstein College of Medicine, tells SELF.

And nope, this is not a good thing. Higher levels of the drug can come with an increased risk of side effects. Depending on the med, this can include serious health hazards like liver and muscle damage or even kidney failure.

But in a few cases, as more recent research has shown, grapefruit can actually have the opposite effect on some meds—causing a decrease in the drug concentration within your body. The compounds in grapefruit can hamper the function of proteins known as drug transporters, which ferry the medication into your cells to be absorbed. Ultimately, this allows less of the drug to enter your blood, reducing its effectiveness.

You can expect the effects from grapefruit to stick around for a while—typically around 24 to 72 hours, according to Dr. Guo. Keep in mind that the duration will be proportional to the amount of the fruit too: The more you take in, the longer the effects will last. What’s more, not everyone will react the same way: The effects of grapefruit on meds depend in part on your unique physiology, since the amount of the CYP3A4 enzyme varies from person to person.

Which medications should not be taken with grapefruit?

There are a whole bunch: In a 2src13 review published in The Canadian Medical Association Journal, researchers estimated that more than 85 drugs are known or predicted to be affected by grapefruit consumption. Here are a few examples of specific types and products that have been documented to interact with the fruit, according to the FDA. Note that not all drugs in these classes will have the same interactions.

Cholesterol-lowering statins, like Zocor (simvastatin) and Lipitor (atorvastatin)
Calcium channel blockers that lower high blood pressure, like Procardia and Adalat CC (both nifedipine)
Organ-transplant rejection medications, like Neoral and Sandimmune (both cyclosporine)
Anxiety medications like BuSpar (buspirone)
Corticosteroids that treat Crohn’s disease or ulcerative colitis, like Entocort EC and Uceris (both budesonide)
Medications that treat abnormal heart rhythms, like Pacerone and Cordarone (both amiodarone)
Some antihistamines (allergy medications), like Allegra (fexofenadine); fexofenadine is an example of one of the few cases where grapefruit reduces the amount of the drug in your blood.

And this list above isn’t exhaustive either. Our best advice: When in doubt, ask your health care provider or pharmacist if your medication happens to be among that number, or check the accompanying information sheet or drug facts label.

Do I need to worry about all grapefruit products or just the fruit itself?

Besides the intact fruit itself (including slices or pulp), grapefruit juice can also cause these issues. In fact, it could even pose a higher risk, according to Dr. Guo. Because the juice usually comes from multiple grapefruits rather than just one, it actually contains more furanocoumarins, making the effect more potent, Dr. Guo explains.

What’s more, it doesn’t take much to feel those effects. Even small amounts of grapefruit juice can have a measurable impact—say, 2srcsrc to 25src milliliters, or around half the size of a Poland Spring water bottle. Per Harvard Health, a single glass can reduce the amount of CYP3A4 enzyme by nearly 5src%. (By comparison, you’d need to eat about one whole grapefruit to achieve that drop.) “So that could potentially mess with the effectiveness of the drugs,” Van Eck says.

If you’re not sure whether a specific food or beverage contains actual grapefruit or grapefruit juice (rather than, say, artificial flavoring), take a look at the ingredients list on the packaging, according to Dr. Guo.

Do other types of fruit interact with meds too?

Grapefruit is definitely the most prominent example, but some other types of citrus fruit can mess with meds in your body as well, according to Dr. Guo. These include the bitter orange (a.k.a. the Seville orange), which is often found in marmalade; the pomelo, which is native to Asia and has been nicknamed the “Chinese grapefruit”; and the tangelo, a cross between tangerines and grapefruit. Like grapefruit, all of these contain furanocoumarins, so they can have the same effects on medication.

Uh-oh: My medication is on the list. Is there a safe way to keep enjoying grapefruit?

Sorry, but the experts say no. Besides messing with the potency of your pills, taking grapefruit with medication can potentially cause unpleasant (or, like we said above, dangerous) side effects. What to watch out for “depends on what medication you’re taking,” Dr. Guo says. High blood levels of calcium channel blockers can lower your blood pressure and slow your heart rate, for example, so you may experience dizziness or fainting. On the other hand, immunosuppressants like tacrolimus could cause shaking, according to Dr. Guo. You could be in for muscle pain and weakness with statins. Meds that treat irregular heart rhythms? Irregular heartbeats and heart palpitations.

“Usually, we’ll tell patients just to avoid it completely,” Dr. Guo says. Same goes for the bitter orange, pomelo, and tangelo listed above. Other alternatives out there that would make a safe swap include citrus fruits like lemons, limes, and oranges—if you need more of that tang—and pears, apples, cherries, and bananas if you can go sweeter. In fact, “almost all other fruits are safe to take,” Dr. Guo says. Vegetables are totally fine too.

And if you really can’t bring yourself to cut grapefruit or grapefruit juice out of your diet entirely? You can ask your doctor if you can switch to an alternative med in the same family that has a lower risk of interacting with the fruit—say, the calcium channel blocker nifedipine could potentially be replaced by verapamil, diltiazem, or amlodipine, according to Harvard Health. Similarly, simvastatin and atorvastatin might be able to be swapped out for other statins like fluvastatin, pravastatin, and rosuvastatin.

If a change-up isn’t possible, at least try to avoid taking your meds and consuming grapefruit at the same time—definitely do not use a glass of it to wash down your pills— and keep the amount you eat or drink to a minimum. The bottom line: “If you’re on these medications, you probably don’t really want to be eating grapefruit regularly,” Van Eck says. “I wouldn’t consume it on a daily basis or even consume large quantities at any time.”