What is a drug-food interaction?
A drug-food interaction happens when the food you eat or drink affects the ingredients in a medicine you are taking so the medicine can't work the way it should.
Drug-food interactions can happen with both prescription and over-the-counter medicines, including antacids, vitamins and iron pills.
How does grapefruit interact with medicines?
Eating grapefruit or drinking grapefruit juice affects how your body processes certain medicines. For most drugs that interact with grapefruit, the chemicals in grapefruit cause your body to absorb either too much or not enough medicine into your bloodstream. This makes it more likely that you will experience side effects from the medicine, or that your medicine won’t be effective. Certain types of oranges, such as pomelo and seville, can also cause similar effects.
Interactions can happen up to 3 days after eating or drinking grapefruit. This means you cannot drink grapefruit juice in the morning and take your medicines later in the day to stop possible medicine interactions.
Do all medicines interact with grapefruit?
Not all medicines interact with grapefruit, but many commonly prescribed medicines do. Examples include medicines to treat:
- High cholesterol: atorvastatin, lovastatin and simvastatin
(Note: pravastatin does not interact with grapefruit)
- High blood pressure: felodipine, nifedipine, nimodipine and nisoldipine
- Heart arrhythmia (a condition that occurs when your heartbeat is abnormal): amiodarone
- Depression and anxiety: buspirone and sertraline
- Human immunodeficiency virus (HIV): saquinavir
- Organ transplants (often prescribed to help suppress the immune system in people who have recently received organ transplants): cyclosporine and tacrolimus
- Allergies: fexofenadine
- Erectile dysfunction: sildenafil
If you don't know if the medicine you are taking interacts with grapefruit, ask your doctor or pharmacist. Your doctor can usually prescribe another medicine that doesn't interact with grapefruit.
Do all fruit juices interact with medicines?
Grapefruits, pomelo oranges and seville oranges are the only fruits known to cause interactions with medicines. All other fruit juices, even other citrus juices, are safe to drink when taking medicine.
What if I take a medicine that interacts with grapefruit?
An interaction can occur even if you eat or drink a small amount of grapefruit. However, if you like grapefruit and want to continue to enjoy it, ask your doctor if there is a different medicine for you that doesn't interact with grapefruit.
Written by familydoctor.org editorial staff