A bad combination: grapefruit and blood pressure medicines
Grapefruit and grapefruit juice taste refreshing and are a popular source of vitamin C. But they aren't always harmless. If you take tablets, you should talk with your doctor about whether grapefruit or its juice could increase the effect of your medications. 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 occur?
Our bodies use various enzyme systems to break down foreign or harmful substances. The system relevant here is found in the intestinal lining and the liver. These enzymes help break down the active ingredient in a medicine. Grapefruit juice can block these enzymes so they don't work properly. As a result, the drug isn't broken down as much as usual. More of the active substance gets into the bloodstream and can build up in the body.
For example, you might take one tablet a day. Normally a certain amount of the active ingredient is broken down by the body's enzymes, so the next tablet is needed the following day to maintain the desired effect. If the enzymes are blocked, the drug can't be broken down as intended. A larger amount than expected reaches the bloodstream and the drug's effect is increased. When you take the next tablet, some of the previous dose may still be present, and the drug can accumulate.
However, it would be reckless to assume you can reduce your tablet dose this way. Because you can't predict how much of the drug will be broken down, you also can't predict 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 monitor their blood pressure every day.
Our content is based on carefully researched, evidence-based data and is continuously updated (as of 03/2024).
Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care, and has led BloodPressureDB's specialist editorial team since 2015. Thanks to her extensive additional qualifications as a paramedic, first responder and in various therapy and emergency areas, she provides solid, practical and reliably reviewed information.
Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care, and has led BloodPressureDB's specialist editorial team since 2015. Thanks to her extensive additional qualifications as a paramedic, first responder and in various therapy and emergency areas, she provides solid, practical and reliably reviewed information.
We hope you found the article helpful. For good blood pressure control, it's important to take your medications correctly. Our app BloodPressureDB 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.
