Grapefruit and juice can be a good part of a healthy diet as it contains some vitamins and nutrients your body requires to function properly. When it affects the manner in which your medicine works, that becomes an issue, high blood pressure and arrhythmia are of high concern in that matter especially and this interaction can be a concern according to Shiew Mei Huang, PhD, of the U.S. Food and Drug Administration.
The FDA requires some over the counter and prescriptions include warnings against the interaction. The severity may be different from person to person depending on the amount ingested and the drug.
Most drugs are metabolized in the small intestine with help of the enzyme CYP3A4, grapefruit can inhibit that from happening, so more enters the blood and stays longer instead of being metabolized. The amount of CYP3A4 in the body varies for each person, contributing to the differences of side effects on the same prescription.
When most drugs interact with grapefruit, it will allow more of the drug to enter your system which causes more side effects. Such as too much statin drugs staying in your blood may increase risk of muscle and liver damage that may lead to kidney failure. While it has been known for years it can cause this, recent studies have shown it can also have the reverse effect on some drugs, says Huang.
You should always talk to your health care provider, pharmacist and doctor along with reading all information provided with the prescription to find out you much you can ingest, how it will affect you, and if there are any other substances that also may affect you while taking the medicine.