Low in fat and high in vitamins, grapefruit is a tasty decision for a healthier diet and a healthier heart. However, according to the 2006 issue of "American Family Physician," Dr. Amy L. Stump indicates that by decreasing the intestinal and liver enzyme P450 3A4, an enzyme vital in the metabolism of numerous medications, grapefruit can cause a sharp increase in drug levels within the body. This interaction can cause several toxic side effects. Consult your doctor before starting a grapefruit diet, especially if you are taking medications.
Antiarrhythmic Medication
Antiarrhythmic medications are used for the treatment of heart arrhythmias, a rapid inefficient beating of the heart. According Dr. Stump, anti-arrhythmic medication such as amiodarone, disopyramide and quinidine can interact with grapefruit, causing an unsafe blood level of these drugs to occur. High levels of these medications can cause several toxic events including an unsafe drop in heart rate, liver toxicity and thyroid toxicity. Other heart medications may also have an effect.
Immunosuppressant Medications
Immunosuppressant medications are a specialized medication commonly used for the suppression of the immune system during organ transplantation in order to lessen the chance of organ rejection by the patient, according to MayoClinic.com. These can also be used to treat certain autoimmune diseases. Grapefruit can increase the levels of these medications, which according to Dr. Stump include cyclosporine and tacrolimus. Increased levels of this medication can cause liver, and renal toxicity, as well as higher suppression of the immune system, increasing infection risk.
Statin Medications
Statins, such as atorvastatin, lovastatin, and simvastatin, are medications that are prescribed for the lowering of high cholesterol levels. According to Dr. Amy L. Stamp, patients that also ingest grapefruit run the risk of increasing the blood levels of this medication. Excessively high levels of statins can cause headaches, stomach aches, liver inflammation and muscle weakness.
Calcium Channel Blockers
Calcium channel blockers are often prescribed to treat high blood pressure, irregular heartbeat and chest pain relief. Calcium channel blockers, which include felodipine, nicardipine, nifedipine, nimodipine, and nisoldipin, can cause rapid heart rate when taken with grapefruit. Other effects may be excessively low blood pressure, dizziness and, in rare cases, a heart attack can occur.
Serious Interaction
The interaction of grapefruit with certain medications is a well studied phenomenon and should not be taken lightly. Always listen to the advice your doctor and your pharmacist provide in regards to the safe practices necessary to ingest your medication. If in doubt ask your doctor or pharmacist. Other medications may interact with grapefruit as well.
References
- "American Family Physician"; Management of Grapefruit-Drug Interactions; Amy L. Stump, Terri Mayo, and Alan Blum; August 2006
- American Heart Association. Learn and live: Delicious decisions
- Mayo Clinic: Grapefruit
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