What is in grapefruit that when taken with some medication it can cause a reaction?
I don’t really have all the answers but it depends on the medicine, It is not known exactly what grapefruit juice contains that causes these drug interactions. Some researchers think that narningenin, DHB, or both are the compounds in grapefruit juice that may be responsible for the interaction.1,2,3 What we do know is that some drugs need certain natural enzymes in the body to break them down so that medicine can be eliminated from the body. Grapefruit juice interferes with one of these enzymes, CYP3A4. It may cause some medicine to build up in the body, leading to unwanted side effects. The amount of CYP3A4 found in a person will vary from person to person. People with higher amounts of the enzyme are affected when grapefruit juice is taken with medicine more often than people with lower amounts. Not all citrus juices contain narningenin or DHB. For this reason, citrus juices such as orange juice have not been shown to affect this enzyme.2 The following is a partial list of medicatio
