Health & Wellness

Medication and grapefruit juice: not always a good mix!


Did you know that grapefruit juice can alter the effect of some medications, and in some cases, increase the risk of side-effects? It is therefore important to know your medication and to find out about possible effects of such a combination on your treatment.

Les médicaments et le jus de pamplemousse

Grapefruit and medication interactions

Eating grapefruit or drinking grapefruit juice (fresh or frozen) may increase the effect of some medications taken orally. Less frequently, it may reduce its effect. Thus, in most cases, it may increase the risk of unwanted side-effects. In addition to grapefruit, Seville oranges (bitter oranges often used in marmalade), pomelos/tangelos and limes may produce similar effects. Most other citrus fruit, such as naturally sweet oranges (for example, Navel or Valencia oranges), lemons and tangerines, are considered safe.

Grapefruits contain substances that reduce the transformation and elimination of certain medications by the body. The quantity of medication active in the blood is therefore increased, and side-effects can occur.

Which medications are affected by grapefruit?

Several medications are affected by grapefruit and its juice. Among them are medications used to treat the following health problems:

  • anxiety
  • arrhythmia (irregular heartbeat)
  • cancer
  • depression
  • erectile dysfunction
  • organ graft
  • high cholesterol
  • high blood pressure
  • gastroesophageal reflux

A real risk: caution required

It is important to know that as little as one glass of grapefruit juice (250 ml or 8 ounces) or one whole grapefruit may increase the amount of medication going into the blood. This phenomenon concerns only some medications. The scope of the interaction and its effects depend on the quantity ingested. It is also important to know that the effects of consuming grapefruit can last up to three days in the body. That means you cannot get around it by drinking a glass of juice in the morning and then taking your medication in the evening.

The consequences of the interaction will vary according to the medication involved and the type of grapefruit. As well, the degree of interaction may vary from one person to another and from one day to the next. All these factors mean that it is difficult to adapt the dose of medication accordingly. The best solution is therefore to avoid grapefruit and its juice (as well as Seville oranges, limes, tangelos and their juice) until you have checked with your pharmacist or your doctor whether these fruits are compatible with your medication. If they are not, sometimes it is possible to choose a different medication that will not be affected by consumption of these fruits.

Tips for consuming grapefruit safely

To reduce the risk of side-effects related to eating grapefruit or drinking grapefruit juice while taking medication:

  • Avoid consuming grapefruit or its juice until you have checked with your pharmacist or your doctor whether they will alter the effects of your medication.
  • Read the labels on all foods and natural healthcare products to make sure they do not contain any grapefruit, Seville orange, tangelo, lime or juice from these citrus fruits.
  • Avoid taking medications in combination with any of the citrus fruits listed above before consulting a healthcare professional.

Your pharmacist is a good advisor, well equipped to verify the interactions with your medications. He or she will be able to tell you if you can consume grapefruit and grapefruit products without any risks to your health. You will benefit more from your consumption of fruits if they mix well with your medication!

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