Grapefruit and Medication Interactions to Watch Out For | LowestMed

Grapefruit is a common morning treat, and for good reason. This little powerhouse of a fruit packs a nutritional punch, with fiber, vitamin C, vitamin A, potassium, and cancer-fighting phytochemicals like lycopene. But mixed in with all that goodness is a little compound called furanocoumarin, which isn’t exactly ideal for grapefruit and medication interactions.

The exact mechanism that furanocoumarin inhibits is the activity of a specific enzyme that is responsible for metabolizing and breaking down toxins and drugs – specifically the cytochrome P450 3A4 enzyme, if you’re interested. This slows down how quickly the medication is processed by your body and increases its concentration in your bloodstream.

Why you shouldn’t eat grapefruit and certain medications together

In some cases, it blocks the mechanism that moves the drug into your body, decreasing the amount and decreasing its effect. And these spell trouble if you’re taking some types of medication.

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Grapefruit and Medication Interactions You Should Be Aware Of

1. Cholesterol Lowering Statins and Grapefruit

This class of drugs is used to lower cholesterol in your body, by helping lower the amount your body normally makes. They also increase the reabsorption rate of what cholesterol is already in your body.

There are two medications that react very strongly with grapefruit. These are Liptor (atorvastatin), and Zocor (simvastatin). If you’re taking one of these two, you should definitely avoid grapefruit.

The side effects from grapefruit interfering with the statins include muscle and joint pain as well as possible liver damage, and muscle breakdown. You can also experience kidney failure, confusion and memory loss.

2. High Blood Pressure Calcium-Channel Blocking Meds

When the furanocoumarin in grapefruit interferes with your calcium-channel blocking medication, it allows more of those meds to enter your blood stream. Because the meds are designed to lower your blood pressure, too much of it can drop your blood pressure too quickly. This can lead to dizziness; it can even cause you to pass out.

Examples of calcium-channel blocking medication that should not be combined with grapefruit are Adalat and Procardia (nifedipine), and Plendil (felodipine).

3. That Little Blue Pill

Because grapefruit allows more of a specific drug to enter your system, there’s also trouble when you combine it with Viagra (sildenafil). It also delays how quickly your body absorbs the Viagra.

This one-two punch can lead to some trouble for people expecting a certain reaction in a certain amount of time. The directions say to use Viagra one hour before sexual activity is expected. With the delayed absorption caused by grapefruit juice, that hour may turn into two or even three.

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4. Sedatives and Grapefruit

Benzodiazepines are a type of medication that is commonly used as a sedative. Certain benzodiazepines are also used as anti-anxiety drugs or anti-seizure medication.

When you take grapefruit with the benzos, you’re going to get higher than normal concentrations of the drug in your bloodstream. This is going to make the drugs you are taking seem more effective, leading to an amplification of your normal dosage.

In some cases, this amplification can have drastic side effects. Some of these include slowed reaction times, speech problems, increased salivation, difficulty breathing, and drowsiness. Additional side effects can actually counter the desired effects. That means you can experience an increase in anxiety, irritability, and even depressive thoughts.

Other medications affected by grapefruit are:

  • Some corticosteroids, such as budesonide
  • A variety of heart medications, including amiodarone (Pacerone, Nexterone)
  • Several allergy medication, like Allegra (fexofenadine)

It’s not just grapefruit either. Other citrus fruits that are relatives of grapefruit can also have this effect. This includes pomelos, and tangelos. It also includes Seville oranges, which are often used to make orange marmalade. Make sure that if you’re taking any medications that can potentially interact with grapefruit that you’re reading ingredients of anything citrusy.

Something to always remember

Just remember that when you start a new drug, it’s very important that you discuss your diet and any potential drug interactions there might be. Grapefruit isn’t the only thing that interacts and interferes with common medications. There are always other interactions with your existing prescriptions. It’s much better to be safe than sorry.

LowestMed’s Health Information Center is meant for educational purposes and is not intended for medical advice. If you would like to recommend any story ideas, feel free to contact us.