Don’t take your medicine with juice. This should become a mantra for medicine-takers, as researchers indicate that it is not just grapefruit juice that impacts drug absorption, but also apple and orange juice and possibly other fruit juices as well. This is news to pay attention to, as some of the medications that can be affected are used to treat serious medical conditions such as heart disease, cancer, organ-transplant rejection and infections.
David G. Bailey, PhD, in the division of clinical pharmacology with the University of Western Ontario in London, Ontario, has studied the effects of grapefruit, orange and apple juices on the antihistamine fexofenadine (Allegra), which he says represents a whole class of drugs. In the past, other researchers have shown that juices, grapefriut, orange and/or apple, can affect the absorption of the anticancer agent etoposide (Etopophos) … beta blockers used to treat high blood pressure and prevent heart attacks such as Atenolol (tenormin) and talinolol (Cordanum) … cyclosporine, a drug taken to prevent rejection of transplanted organs… and certain antibiotics such as ciprofloxacin (Cipro), levofloxacin (Levaquin) and itraconazole (Sporanox). Depending on the drug and the juice, you may not get enough of the drug or you may get too much.
In Dr. Bailey’s latest study, volunteers took Allegra with either a single glass of grapefruit juice, water containing only naringin (a bitter-tasting substance in grapefruit juice that is what causes the problem), or water. Where previous studies had found that grapefruit juice boosted the effect of some drugs, possibly to a toxic level, this study found that when subjects took Allegra with grapefruit juice, only half the dose was absorbed. He said that other juices, including orange and apple juices, have compounds similar to naringin that may have the same effect. This means drinking common juices with medication can reduce significantly the amount of drug in the bloodstream, therefore, the drug’s effectiveness. Dr. Bailey presented his study results at the 236th National Meeting of the American Chemical Society.
Scientists acknowledge that the list of which juices interact with which drugs is very much a work in progress and is not yet definitive. Additionally, drug-food interactions can occur from four hours to three days after juice, depending on whether the drug decreases or increases potency. Dr. Bailey advises patients to consult with their doctor or pharmacist before taking any medications with fruits and juices. “The most consistent effect is achieved if a drug is taken with a glass of plain old water, preferably on an empty stomach, unless you’ve received different directions from your doctor,” said Dr. Bailey.
