Some types of grapefruit juice can elevate the level of blood pressure medication in your body to an unhealthy and dangerous extreme. Channel blockers, in particular, may cause serious interactions when mixed with grapefruit. Some other heart-related drugs -- statins, for example -- as well as a long list of prescribed and over-the-counter medications can react dangerously with grapefruit juice.
Negative Reaction With Calcium Channel Blockers
Calcium channel blockers work to lower blood pressure by stopping calcium from being able to enter your blood vessels and heart. Two calcium channel blockers -- nefedipine and felodipine -- can prove dangerous when consumed with grapefruit juice. Grapefruit juice prohibits your body's CYP34A enzymes from breaking down medication. This enables more of the medication to enter your bloodstream, which means you will be getting a higher dose than prescribed. With certain medications, this unusually high dose poses danger. If your body retains an excess of calcium channel blockers, your blood pressure could drop too low and your heart could stop beating.
Negative Reaction With Statins
Excess fat in your arteries, otherwise known as high cholesterol, can cause high blood pressure. High blood pressure can also create high cholesterol. High blood pressure can cause your arteries to stretch and tear. As your body repairs the damage, scar tissue forms. Unhealthy lipids in your bloodstream -- low-density lipoprotein and triglycerides -- get trapped by the scar tissue and accumulate more rapidly in your arteries. If you have been prescribed statins to lower your cholesterol, you should not take them with grapefruit juice. Statins -- but not all cholesterol-lowering medications -- may react dangerously with grapefruit juice.
Positives of Red Grapefruit
If you do not take heart-related medications, eating grapefruit -- especially red grapefruit -- could prove helpful for lowering blood pressure and cholesterol. A 2006 edition of "Journal of Agriculture and Food Chemistry" published the results of a grapefruit study led by Shela Gorinstein, a researcher at the Hebrew University of Jerusalem. In Gorinstein's study, 57 individuals with high blood pressure ate grapefruit for 30 days and all experienced a reduction in their triglyceride levels. Red grapefruit stood out as being the most helpful in reducing triglyceride levels. Lower triglyceride levels are likely to naturally lower blood pressure.
Other Drugs That React Negatively
Do not consume grapefruit juice with birth control pills, as this could lead to blood clots, heart attacks or strokes. Grapefruit juice also increases the potential side effects of some antidepressants, anti-anxiety drugs and other psychiatric medications. If you take immunosuppressants to prevent organ rejection after a transplant, you should abstain from drinking grapefruit juice. Before combining grapefruit juice with any medications, whether prescribed or over the counter, first consult your doctor to make sure it's safe. A long list of medications can cause serious, even fatal, side effects when combined with grapefruit juice.
References
- The Harvard Medical School Family Health Guide: Grapefruit and Medication: A Cautionary Note; February 2006
- MayoClinic.com: Calcium Channel Blockers
- "The New York Times"; Experts Reveal the Secret Powers of Grapefruit Juice; Nicholas Bakalar; March 2006
- American Heart Association: About High Blood Pressure
- "The Evening Standard"; Have a Heart, Have a Red Grapefruit; Mark Prigg; February 2006
- "Journal of Agriculture and Food Chemistry"; Red Grapefruit Positively Influences Serum Triglyceride Level in Patients Suffering From Coronary Atherosclerosis: Studies In Vitro and in Human; Shela Gorinstein, et al.; February 2006
