The grapefruit and medicine effect

NPS MedicineWise has published new information about interactions between grapefruit and medicines that provides tips to help people avoid any harmful effects.

A review published in the Canadian Medical Association Journal last month highlights more than 85 medicines may interact with grapefruit to cause side effects — some which may be serious.

While it’s been known for some time that the humble grapefruit can interact with medicines, the review points to a rising number of medicines that may interact with grapefruit to potentially cause serious side effects — up from 17 to 43 in recent years.

Clinical adviser at NPS MedicineWise, Dr Andrew Boyden, says interactions can happen when medicines mix with certain foods or drink — and grapefruit is one example.

“Grapefruit juice interacts with several common medicines, making them work too strongly or causing side effects,” Dr Boyden says.

“Being medicine wise when it comes to grapefruit interactions is particularly important because of the large and varied list of medicines that could interact.”

The list includes some commonly prescribed medications including some statins (cholesterollowering medicines), some types of medicines for heart conditions and high blood pressure, as well as medicines that people may be taking only for a short period of time such as some antimalarial medicines, antibiotics and cough and cold medicines.

People taking these medicines are advised not to eat grapefruit or drink grapefruit juice at all, because even one glass of juice can have an effect.

Interactions can occur even when the grapefruit or juice is eaten or drunk at a different time to taking the medicine.

Dr Boyden says people taking medicines who want to consume grapefruit are encouraged to talk with their doctor or pharmacist or call the NPS Medicines Line.

Over the counter and complementary medicines (such as herbs and nutritional supplements) might also interact with grapefruit juice, not just prescription medicines.

For more information on prescription, over the counter and complementary medicines (herbal, ‘natural’, vitamins and minerals) from a health professional, call NPS Medicines Line on 1300 MEDICINE (1300 633 424) for the cost of a local call (calls from mobiles may cost more). Hours of operation are Monday–Friday 9am–5pm AEST (excluding public holidays).

An indicative list of the affected medicines is available on the NPS website.