Grapefruit juice is a tangy, refreshing beverage many people enjoy. It’s packed with vitamin C and potassium, which are essential for a healthy body. However, this seemingly harmless drink can have significant interactions with certain medications, potentially jeopardizing your health.
The Science Behind the Interaction
Grapefruit juice can interfere with how your body metabolizes certain drugs. Many medications are broken down by an enzyme called CYP3A4 in the small intestine. Grapefruit juice can block the action of this enzyme, preventing the drug from being properly metabolized. This leads to a higher concentration of the drug entering your bloodstream, potentially causing increased side effects.
However, grapefruit juice can also have the opposite effect on a few other drugs. Instead of changing metabolism, grapefruit juice can affect proteins in the body known as drug transporters, some of which help move a drug into our cells for absorption. As a result, less of the drug enters the blood and the drug may not work as well, Huang says.
It’s also worth noting that the amount of the CYP3A4 enzyme in the intestine varies from person to person, so grapefruit juice may affect people differently even when they take the same drug.
Which Medications Are Affected?
The FDA warns that grapefruit juice can cause problems with certain types of drugs. Here are some examples of medications that can be affected by grapefruit juice:
- Some statins to lower cholesterol, such as Zocor (simvastatin) and Lipitor (atorvastatin).
- Some drugs that treat high blood pressure, such as Procardia and Adalat CC (both nifedipine).
- Some organ-transplant rejection drugs, such as Neoral and Sandimmune capsule or oral solution (both cyclosporine).
- Some anti-anxiety drugs, such as BuSpar (buspirone).
- Some corticosteroids that treat Crohn’s disease or ulcerative colitis, such as Entocort EC and Uceris tablet (both budesonide).
- Some drugs that treat abnormal heart rhythms, such as Pacerone and Cordarone tablet (both amiodarone).
- Some antihistamines, such as Allegra (fexofenadine).
It is important to note that grapefruit juice does not affect all drugs in these categories. The severity of the interaction can also vary depending on the person, the drug, and the amount of grapefruit juice consumed.
The Risks of Mixing Grapefruit Juice and Medication
When grapefruit juice interferes with the metabolism of certain drugs, it can lead to a variety of adverse effects. For example, if you drink a lot of grapefruit juice while taking certain statins, too much of the drug may stay in your body, increasing your risk for liver and muscle damage that can lead to kidney failure.
In other cases, grapefruit juice can decrease the effectiveness of a drug. For instance, fexofenadine (Allegra) may not work as well if taken with grapefruit, orange, or apple juice.
For 43 of the 85 drugs now on the list, consumption with grapefruit can be life-threatening. Older people may be more vulnerable because they are more likely to be both taking medications and drinking more grapefruit juice.
Someone taking simvastatin (brand name Zocor) who also drinks a small 200-milliliter, or 6.7 ounces, glass of grapefruit juice once a day for three days could see blood levels of the drug triple, increasing the risk for kidney damage. It is not enough to avoid taking your medicine at the same time as grapefruit. You must avoid consuming grapefruit the whole period that you are on the medication.
What to Do If You’re Concerned
If you’re taking medication, it’s crucial to be aware of potential interactions with grapefruit juice. Here’s what you should do:
- Consult your healthcare provider: Talk to your doctor or pharmacist about all the medications you’re taking, including prescription drugs, over-the-counter medications, and supplements. Ask if any of these medications may interact with grapefruit juice.
- Read medication labels: Carefully read any information provided with your prescription or non-prescription drugs. Look for warnings about grapefruit juice or other foods that may affect the drug.
- Avoid grapefruit juice if necessary: If your medication interacts with grapefruit juice, the safest course of action is to avoid it altogether. In some cases, your doctor may be able to prescribe an alternative medication that does not interact with grapefruit juice.
- Check other citrus fruits: The interaction also can be caused by other citrus fruits, including Seville oranges, limes, and pomelos; one published case report has suggested that pomegranate may increase the potency of certain drugs.
Enjoying Grapefruit Safely
If you’re not taking any medications that interact with grapefruit juice, you can generally enjoy it as part of a healthy diet. Grapefruit is a good source of vitamin C, potassium, and other nutrients that your body needs to function properly.
Here’s a simple recipe for a refreshing grapefruit juice:
Ginger-Kissed Grapefruit Juice
Ingredients:
- 1 1/3 cups fresh grapefruit juice (about 2 grapefruits)
- 1/2 cup fresh lime juice (about 2 juicy limes)
- 2 tablespoons grated ginger
- 3 tablespoons natural cane sugar (or to taste)
- 1 cup water
Instructions:
- Combine all ingredients in a blender.
- Blend until smooth.
- Adjust sweetness and water to taste.
- Serve over ice and enjoy!
This juice is quite strong, but invigorating! You can make it more or less sweet, to your tastes. And you can mix it with more or less water sparkling water, also to taste.