Grapefruit and Medication

Chronic diseases
different citrus

When you received your medication, the pharmacist mentioned that you should avoid taking grapefruit with certain medications? This is not a recommendation to be taken lightly. In some cases, citrus fruits and medication are not a good match!

How Does It Work?

Consumption of grapefruit can potentially affect the effect of medications; either by increasing their adverse effects or by decreasing their desired effect. When we ingest a drug, it is metabolized (transformed) by our body to obtain the desired effect. However, grapefruit has the potential to inhibit (prevent) the body from properly processing the drug. This means that a larger dose of the drug than expected can end up in the bloodstream! 

The problem? We don’t know exactly how much the grapefruit changes the dose absorbed by the body and how much the effects are amplified. This can be very dangerous and can also increase the risk of overdose! To this day, it is believed that furocoumarins present in grapefruit (and certain other citrus fruits) are responsible for this interaction.

Some drugs are more concerned than others, such as those for anxiety, depression, cholesterol, reflux and arrhythmias. However, this list is neither exhaustive nor a guide. We must therefore rely on the recommendations made by the pharmacist.

Before, Now and After

The recommendation not to take your medication with grapefruit does not only mean to avoid swallowing your pill with a sip of grapefruit juice. It also means not taking it before, with, and even after taking the medication. The effects of one to two glasses of grapefruit juice can last up to 72 hours (3 days !) after its consumption.

Not Just Grapefruit

This guideline is not just for grapefruit and its juice. Some other citrus fruits, such as pomelos and Seville oranges, may have similar effects. However, there is no need to be alarmed. Regular sweet oranges and the traditional orange juice found in grocery stores are safe, as are lemons. 


Although grapefruits are delicious, they should not be consumed if you are taking a medication with a risk of interaction. This is why it is very important to discuss with your pharmacist and to consult a dietician to find alternatives! You can replace your morning grapefruit juice with a regular orange juice or try other savory fruits. Why not even try a mango smoothie?

Registered Dietitian Nutritionist