Risky mix: grapefruit and blood pressure medications
Grapefruit and grapefruit juice taste refreshing and are especially popular as a source of vitamin C. But they're not always a good choice for everyone. If you take tablets, talk with your doctor to find out whether grapefruit or its juice could increase the effect of your medicines. This applies not only to taking tablets with grapefruit juice, but also 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 occur?
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. However, grapefruit juice can block these enzymes, preventing them from doing their job properly. As a result, the medicine cannot be broken down by the body to the usual extent. More of the active ingredient enters the bloodstream and can therefore 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 enzymes in the body. That is why the next tablet is due the following day to achieve the desired effect. However, if the enzymes are blocked, the medicine cannot be broken down as intended. More of the active ingredient than intended enters the bloodstream, increasing the medicine's effect. When you take the next tablet, some of the medicine may still be in your body, causing it to build up.
However, it would be reckless to think you could reduce your tablet dose this way. Since it is impossible to predict the extent to which the medication can be broken down, it is also impossible to 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 is from Tensana – the leading app since 2011, helping hundreds of thousands of people monitor their blood pressure every day.
Our content is based on carefully researched, evidence-based data and is continuously updated (as of 12/2025).
Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as outpatient care, and has headed the specialist editorial team at Tensana since 2015. Thanks to her extensive additional qualifications as an emergency medical technician, first responder, and in various areas of therapy and emergency care, she provides well-founded, practical, and reliably verified information.
Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as outpatient care, and has headed the specialist editorial team at Tensana since 2015. Thanks to her extensive additional qualifications as an emergency medical technician, first responder, and in various areas of therapy and emergency care, she provides well-founded, practical, and reliably verified information.
We hope you found the article helpful. For good blood pressure control, it's important to take your medications correctly. Our app Tensana will gladly remind you when to take them.
It also keeps track of your medication supply and notifies you in time when you're running low. This feature is fully available in the free version as well. Get the free app now.
