Grapefruit juice - a negative impact

Health Canada, the Canadian government department responsible for keeping an eye on the health of its people, is advising people this week not to take certain drugs with grapefruit juice.

In a recent statement, Health Canada​ writes that although interactions between grapefruit juice and certain drugs are well documented in the medical and scientific literature, this information may be unknown to the public.

Apparently there are several substances in grapefruit which interfere with the way the body handles certain drugs. Consuming grapefruit juice (fresh or frozen) or grapefruit sections can increase, or less commonly decrease, the effects of some drugs, which could lead to serious or even life-threatening adverse reactions. As little as one glass of grapefruit juice (8 oz or 250 ml) can cause this effect.

Certain drugs and health products used in the treatment of the following medical conditions are known to cause this effect: anxiety; depression, high blood pressure; HIV/AIDS; cancer; irregular heart rhythms; infections; psychotic problems; erectile dysfunction; angina; convulsions; gastrointestinal reflux; high lipid (cholesterol) levels; and organ graft rejections.

Health Canada is advising the public not to drink grapefruit juice or eat grapefruit in any form, if under medication for any of the conditions listed above, until having talked it over with a doctor or pharmacist about the potential for an adverse reaction. The government body also advises, as a precaution, to avoid taking any drug with grapefruit juice until a doctor or pharmacist has said it is safe to do so.

While sweet oranges and their juice do not appear to cause the same reaction, sour orange juice such as that from Seville oranges, may have an effect similar to grapefruit juice. Tangelos are a hybrid of grapefruit and may also interfere with drugs. Most other citrus fruits, such as lemons, limes, citrons, naturally sweet oranges and tangerines, are considered safe.