Don't Take Your Allergy Medications with Fruit Juices

Filed in archive Allergy Medications , Hay Fever , Living with Allergies on August 22, 2008

Photo courtesy of iStockphoto, Jill Chen

If you are taking allergy medications such as allegra (available generically as fexofenadine), better down them with plain water instead of fruit juices. There are substances in fruit juices that block the absorption of the key ingredient in some medicines.

A substance in grapefruit juice called naringin seems to be the culprit. The compound apparently blocks OATP1A2, a transporter molecule in the gut, which carries some drugs from the small intestine into the blood. Orange juice contains hesperidin, a naringin-like substance. The culprit in apple juice remains unidentified.

In their studies, Bailey and colleagues had healthy volunteers take fexofenadine with either a glass of grapefruit juice, a glass of water mixed with naringin, or pure water. Taking the drug with grapefruit juice or the naringin mixture halved the amount of drug that reached the bloodstream.