Grapefruit Interactions With Bipolar Drugs

Combined use can cause increases in drug concentration

Grapefruit juice
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Grapefruit juice may seem like the ideal drink for a good, old-fashioned American breakfast, but when it comes to washing down your bipolar medications, think again. Unlike some types of citrus fruit, grapefruit can interfere with the metabolization of certain drugs, inadvertently increasing their concentration to potentially toxic levels.

Bipolar drugs are not the only ones affected. Also on the no-fly list are medications used to treat everything from high cholesterol and arrhythmia to allergies and HIV.

Even Viagra is complicated by the otherwise healthy effects of grapefruit.

How Grapefruit Interferes with Drug Concentration

A number of psychotropic drugs, including those used treat anxiety, depression, and psychosis, are among the 85 agents grapefruit juice is known to interfere with.

This is because grapefruit contains furanocoumarins, an organic compound which blocks an enzyme that normally breaks down certain medications. This effect means that the drug concentration levels in the blood will be higher than expected. In some cases, this will mean that the intended effect and/or side effects will be stronger, even intolerable.At other times, it could be dangerous.

While other citrus fruits like pomelos, limes, and Seville orange also contain furanocoumarins, they haven't been studied as closely. 

Degrees and Persistence of Effect 

The degree by which grapefruit can affect certain drugs can vary.

For some medications, one small glass of juice can result in what would be equivalent to a double or triple dose.

For example, as much as 99 percent of BuSpar (buspirone) is normally metabolized before the drug enters the bloodstream. When taken with grapefruit juice, the concentration can increase by as much as 400 percent

At the same time, the effects of grapefruit can be long-lasting, interacting with certain drugs anywhere from a few hours to 24 hours after ingestion.

With that being said, not all drugs in a drug class are affected (or affected in the same way) by grapefruit. For many bipolar medications, separating your grapefruit and daily dose by four hours is enough to avoid any interaction. 

Alternately, you can avoid grapefruit altogether and substitute with a (non-Seville) orange juice. 

List of Psychotropic Medications Affected by Grapefruit

All told, there are 15 drugs commonly used to treat symptoms of bipolar disorder that are known to be affected, in differing degrees, by grapefruit:

  • Anafranil (clomipramine)
  • BuSpar (buspirone) 
  • Clozapine (clozaril)
  • Elavil (amitriptyline)
  • Halcion (triazolam)
  • Haldol (haloperidol)
  • Luvox (fluvoxamine)
  • Prozac (fluoxetine)
  • Seroquel (quetiapine)
  • Serzone (nefazodone)
  • Tegretol (carbamazepine)
  • Trazodone (desyrel)
  • Valium (diazepam)
  • Versed (midazolam)
  • Zoloft (sertraline)

A Word From Verywell

Each year, an increasing number of drugs are identified as having a possible interaction with grapefruit. As a result, always read in the packet insert in its entirety to understand which interactions can occur.

Typically, you can find this in or around the fifth paragraph where it would read: "Talk with your doctor before including grapefruit or grapefruit juice in your diet while you are taking this medicine." 

In the end, you can still enjoy the nutritional benefits of grapefruit if taken wisely. The combination of vitamin C, fiber, potassium, lycopene, and choline are key to maintaining a healthy heart and normalizing lipids (particularly triglycerides) in your blood. Speak with your doctor if in doubt.

Source:

Pawelczyk, T. and Kioszewska, I. "Grapefruit juice interactions with psychotropic drugs: advantages and potential risk." Przegl Lek. 2008;65(2):92-5.

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