Every day, millions of people who take medications also drink grapefruit juice. I do. But most don't realize the combination can be toxic and even fatal.

A new study identified eighty-five drugs that interact with grapefruit juice, of which forty-three can cause serious problems. That is more than we previously recognized. Many are common prescriptions, such as Lipitor to lower cholesterol, Nifediac to lower blood pressure, Xanax for anxiety, oxycodone to relieve pain, and even Viagra.

What grapefruit and grapefruit juice do when combined with certain drugs is increase the amount of the active drug in the bloodstream to potentially toxic levels. Normally, a drug is absorbed and begins working soon after it's in the body - moving through the small intestine, into the bloodstream, and then the liver.

During that process, enzymes begin metabolizing or breaking down the drug to remove it from the body - a natural response to rid the body of foreign substances. About half of all drugs are metabolized by an enzyme from a superfamily of enzymes called cytochrome P450.

But this process is compromised when people consume grapefruit or the juice, as well as Seville oranges, tangelos, limes and pomelos, which contain an organic chemical compound called furanocoumarins. These compounds lower cytochrome P450 in the intestine, so that instead of inactivating drugs, more enters the bloodstream. People can suffer liver and kidney damage, GI tract bleeding, respiratory failure, bone marrow suppression, rapid heart rate, and even death. The effect can persist hours after consuming these fruits or juices.

Visit our website and check with your doctor to see if any of your medications should not be combined with grapefruit or its juice.