Grapefruit, an excellent source of vitamin C, beta-carotene, lycopene, and other vital nutrients, becomes extremely toxic when mixed with a growing number of prescription drugs, according to a new Canadian study. Dozens of widely used drugs interact with compounds in the popular citrus fruit, triggering serious complications and even death.
“The number of drugs on the market with the potential to produce serious adverse and in many cases life-threatening effects when combined with grapefruit has markedly increased over the past few years from 17 to 43 in four years,” lead researcher David Bailey of the Lawson Health Research Institute in London, Ontario, told HealthDay.
“There is much greater need for health care professionals to understand grapefruit/drug interactions and to apply this information to the safer use of these drugs in their clinical practice,” he added.
Patients taking certain prescription drugs don’t have to consume large quantities of grapefruit to experience adverse reactions. According to HealthDay, “even small amounts of grapefruit or grapefruit juice have the potential to cause sudden death, acute kidney failure, respiratory failure, gastrointestinal bleeding and other serious side effects when paired with these medications.”
Among the drugs that could become deadly when taken in combination with grapefruit are certain cholesterol drugs such as atorvastatin (Lipitor), simvastatin (Zocor) and lovastatin (Mevacor, Altoprev), the anti-clotting agent clopidogrel (Plavix), blood pressure drugs, cancer treatments, and antibiotics such as erythromycin.
Grapefruit, limes, and Seville oranges (a type of orange commonly used in marmalade) contain furanocoumarins, organic compounds that inhibit an enzyme that normally neutralizes about half the effects of medication. The drugs that interact adversely with grapefruit are all taken orally and aren’t metabolized well by the body, meaning that they largely pass through the body without entering the bloodstream. The furanocoumarins in grapefruit, however, boost the amount of drug metabolized by the body, so that a single drug dose becomes the same as taken multiple doses.
Moreover, the increased absorption of prescription drugs facilitated by grapefruit can have a cumulative effect over time. Dr. Bailey told HealthDay that concentrations of the cholesterol drug Zocor, for example, increase by 330 percent when the drug is taken for three days with a 7-ounce glass of grapefruit juice.