Why can grapefruit be dangerous?
Grapefruit juice is a healthy part of a diet. It has a lot of vitamins, fiber, sugar and minerals and can help with bone growth and weight loss. Though it has many benefits, grapefruit juice could interact with different prescription or over-the-counter medications which is called a drug interaction.
The body eliminates some drugs in the body by breaking them down using enzymes. Enzymes are proteins that speed up chemical reactions. Grapefruit juice can slow down these enzymes, specifically CYP3A4 enzymes in the liver, from working properly. Slowing down drug elimination can lead to having too many drugs active in your body, resulting in serious side effects. The effects of grapefruit juice wears off slowly and can last as long as 72 hours.
What are some examples of known grapefruit juice drug interactions?
There are over 85 drugs that can interact with grapefruit juice. The most common types of medications include:
- Calcium channel blockers (high blood pressure)
- Benzodiazepines (anxiety, sleeping disorders)
- Statins (high cholesterol)
- Antibiotics (to treat infection)
- Immunosuppressants (to prevent rejection of transplanted organs)
- Antiarrhythmics (heart rate medications)
Grapefruit juice does not affect all these drugs. It is important to talk to your doctor to see if your medications could interact with grapefruit juice.
Signs and symptoms of grapefruit juice drug interactions
- Trouble breathing
- Sleepiness
- Dizziness
- Low blood pressure
- Kidney damage
- Irregular heart rates.
How much grapefruit juice is too much?
Even one grapefruit could cause drug interactions. There is no specific amount of grapefruit juice that can cause drug interactions. This is because levels of CYP3A4 enzymes are different in everyone. Grapefruit drug interactions are different depending on the person, amount of grapefruit, and drug.
Who is at risk for this interaction?
The main buyers of grapefruit juice that receive the most drug prescriptions are people over 45 years old. People older than 70 years old and people with liver damage are at risk of stronger side effects.
Are there any other juices I should be aware of?
The main chemicals in grapefruit causing drug interactions are called furanocoumarins.
Other fruits that have this chemical include:
- Seville oranges (commonly used to make orange marmalade)
- Limes
- Pomelo
- Tangelos (a cross between tangerines and grapefruit).
Find out if you should avoid grapefruit juice or other juices
It is important to ask your doctor or pharmacist if your medications can interact with fruit juices.
Other ways to prevent an interaction include:
- Reading the medication sheet that comes with prescription drugs to see if grapefruit juice should be avoided
- Reading the Drug Fact label on your over-the-counter drugs
- If you must avoid grapefruit juice with your medicine, checking the labels of fruit juices to see if they were made with grapefruit juice
- Avoiding other fruit that have furanocoumarins
Written by:
Monida Tum
PharmD Candidate 2024
Temple University School of Pharmacy
References
An Overview of Drug Interactions With Grapefruit Juice. The Journal for Nurse Practitioners. 2020;16(10):774-775. doi:https://doi.org/10.1016/j.nurpra.2020.08.016
Ateş M, Sahin S. Interaction of Statins with Grapefruit Juice. FABAD Journal of Pharmaceutical Sciences. 2023;48(2):337-358. doi:https://doi.org/10.55262/fabadeczacilik.1187441
Bailey DG, Dresser G, Arnold JM. Grapefruit-medication interactions: forbidden fruit or avoidable consequences?. CMAJ. 2013;185(4):309-316. doi:10.1503/cmaj.120951
Grapefruit and medication: A cautionary note: Harvard Health Publishing. Published March 10, 2021. Accessed January 30, 2024. https://www.health.harvard.edu/staying-healthy/grapefruit-and-medication-a-cautionary-note
Grapefruit juice and some drugs don’t mix. Food and Drugs Administration. Published July 1, 2021. Accessed January 30, 2024. https://www.fda.gov/consumers/consumer-updates/grapefruit-juice-and-some-drugs-dont-mix