Compounds in grapefruit juice or in products made from grapefruit can interact with certain types of prescription medications. These interactions may inhibit enzymes needed to metabolize or break down the medication and thus enable its removal from the body. Since it is not metabolized, the medication can build up in the bloodstream, increasing the likelihood of serious side effects. Anti-anxiety drugs, antidepressants, anti-seizure drugs and the statins are examples of medications that can interact with grapefruit products, notes MayoClinic.com
Anti-anxiety Drugs
Buspirone is an oral medication that doctors prescribe for the short-term treatment of the symptoms of anxiety. Before taking buspirone, patients should consult their doctor about consuming grapefruit products while using the medication. The interaction between buspirone and grapefruit may result in very serious side effects such as rapid or irregular heartbeat and lack of balance.
Antidepressants
In an article that appeared in the January 2009 issue of "The World Journal of Biological Psychiatry," researchers describe the effect of grapefruit juice on plasma levels of the antidepressant drug sertraline. Study subjects consisted of eight healthy individuals who consumed either water or grapefruit juice three times a day for five days, and then took oral sertraline on the sixth day. The scientists found that subjects who drank grapefruit juice had higher amounts of sertraline in their blood relative to those who drank water. This increase in sertraline blood level may arise because grapefruit juice contains substances that block certain enzymes which are responsible for the breakdown of drugs in the body.
Anti-Seizure Drugs
Carbamazepine is a prescription medication that can prevent the seizures associated with epilepsy. It works by curtailing the release of the neurotransmitter glutamate from nerve cells in the brain. Grapefruit juice may inhibit the breakdown of carbamazepine, thereby allowing elevated levels of the drug to build up in the blood. These elevated levels may increase the risk of side effects such as a skin rash or peeling, a decrease in the number of red and white blood cells and platelets, dizziness and blurred vision.
Statins
The statins are a group of prescription drugs that can lower cholesterol blood levels in patients who have high cholesterol. Of the six statin drugs available, three of them, lovastatin, simvastatin and atorvastatin, can interact with grapefruit products. In addition, combination drugs that contain these three statins are subject to interactions with grapefruit. The interaction of these statins with compounds in grapefruit disables an enzyme, called CYP3A4, that is needed to break the drugs down; therefore, the drugs build up in the blood. This buildup can lead to serious muscle damage. The interaction persists over time. For example, three days after consuming grapefruit, CYP3A4 is still disabled, notes HealthyCommunities.com.. Fluvastatin, pravastatin and rosuvastatin are less likely to interact, but patients who are taking these drugs should not consume grapefruit products until they have consulted their doctor.
References
- MayoClinic.com: Consumer Health: Grapefruit Juice: Beware of Dangerous Medication Interactions
- Drugs.com: Buspirone
- "The World Journal of Biological Psychiatry"; Grapefruit Juice Alters Plasma Sertralin Levels After Single Ingestion of Sertraline in Healthy Volunteers; Nobuhisa Ueda, et al.; January 2009
- NetDoctor.co.uk: Tegretol Retard (Carbamazepine)
- Healthcommunities.com: Statins and Grapefruit: A Dangerous Combination
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