Risky mix: grapefruit and blood pressure medications
Grapefruit and grapefruit juice taste refreshing and are a popular source of vitamin C. But theyre not always a good choice for everyone. If you take tablets, talk with your doctor to find out whether grapefruit or its juice could strengthen the effect of your medicines. This applies not only to taking tablets with grapefruit juice, but to eating the fruit or drinking the juice at any time during your treatment. Several different drugs can be affected including some blood pressure medications.
How does this interaction happen?
To break down foreign or harmful substances, our bodies use several enzyme systems. The system that matters here is located in the lining of the intestine and in the liver. These enzymes help to break down the active ingredient in a medicine. Grapefruit juice can block these enzymes so they cant do their job properly. As a result, the drug isnt broken down as usual. More of the active ingredient gets into the bloodstream and can build up in the body.
For example, you might take one tablet every day. Normally a certain portion of the active ingredient is broken down by the enzymes. Thats why you take the next tablet the following day to keep the effect. But if the enzymes are blocked, the medicine cant be broken down as expected. More of the drug reaches the blood and the effect is increased. When you take the next tablet, some of the previous dose may still be in your body, so the medicine can accumulate.
It would be reckless to think you could reduce your tablet dose this way. Since you cant predict how much of the drug will be broken down, you also cant say how much will build up in the body.
So if you like grapefruit but need to take tablets, discuss this with your doctor or pharmacist.
Source:
This article comes from BloodPressureDB – the leading app since 2011 that helps hundreds of thousands of people monitor their blood pressure every day.
Our content is based on carefully researched, evidence-based information and is continuously updated (as of 12/2025).
Author Sabine Croci is a certified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care. Since 2015 she has led the editorial team at BloodPressureDB. With additional qualifications as a paramedic, first responder, and training in various therapy and emergency areas, she provides well-founded, practical, and reliably reviewed information.
Author Sabine Croci is a certified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care. Since 2015 she has led the editorial team at BloodPressureDB. With additional qualifications as a paramedic, first responder, and training in various therapy and emergency areas, she provides well-founded, practical, and reliably reviewed information.
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