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wendyzskiI have that warning on my statins (for cholesterol), and other than "it's bad" never knew why.
Now I do. o.O
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mslesa's lj =, and GRAPEFRUIT AND MEDS DON'T MIX
We've all seen the typical warnings on our prescription labels - "Do not take while operating heavy machinery," or "May cause drowsiness." But, then there's the seemingly arbitrary, "Do not eat grapefruit while taking this medicine."
For close to 15 years, doctors have known that grapefruit can cause serious interactions with some medications, but only recently have they come to understand why.
Grapefruit juice, unlike other citrus juices, contains furanocoumarins, a substance that affects the body's absorption of certain medications. Normally, the absorption of these drugs is partially blocked from entering the body by an enzyme in the intestine. However, furanocoumarins prevent this enzyme from working, allowing potentially toxic levels of the drug to enter to body.
In a study of furanocoumarin, researchers from the University of North Carolina at Chapel Hill gave 18 healthy volunteers felodipine, a common blood pressure lowering medication. Some took the drug with orange juice, some with grapefruit juice, and the last group took the drug with grapefruit juice that had the furanocoumarins removed.
Researchers then measured the amount of medication in each patient's blood. They discovered that those who used the furanocoumarin-free grapefruit juice had the same amount of the drug in their blood as those who used orange juice. The patients who drank normal grapefruit juice, however, had up to a 420 percent increase in blood levels of felodipine at any one time. The results of the study are published in the American Journal of Clinical Nutrition.
"This is the best evidence to date that furanocoumarins are the active ingredients in grapefruit juice that cause the interaction with medications," said Dr. Paul Watkins, lead study author.
According to researchers, identifying this chemical could lead to identifying other foods with furanocoumarins that may cause drug interactions. Also, for drugs that do not enter the body easily, furanocoumarins may be added to the pills to help them be absorbed by the intestine. Additionally, by removing this substance from grapefruit juice, it may be possible to create commercially available grapefruit juice without the medical concerns.
"The interaction between grapefruit juice and certain medications is certainly a hot topic," says Ellen Guthrie, Pharm.D. "These include calcium channel blockers - such as Plendil and Procardia - which are often prescribed for high blood pressure; Sandimmune, a drug given to people who have had organ transplants; sedatives, such as Xanax and Valium; and many herbal medications. Some other classes of drugs, including steroids, painkillers and antihistamines, may also interact with grapefruit juice. Interestingly, a few studies have actually focused on the effects of daily grapefruit juice intake as a means to reduce the need for medication. While this is never advised without prior consultation with your doctor, it does seem to be gaining popularity"
Wow.
Now I do. o.O
Cross-posed from
mslesa's lj =, and GRAPEFRUIT AND MEDS DON'T MIXWe've all seen the typical warnings on our prescription labels - "Do not take while operating heavy machinery," or "May cause drowsiness." But, then there's the seemingly arbitrary, "Do not eat grapefruit while taking this medicine."
For close to 15 years, doctors have known that grapefruit can cause serious interactions with some medications, but only recently have they come to understand why.
Grapefruit juice, unlike other citrus juices, contains furanocoumarins, a substance that affects the body's absorption of certain medications. Normally, the absorption of these drugs is partially blocked from entering the body by an enzyme in the intestine. However, furanocoumarins prevent this enzyme from working, allowing potentially toxic levels of the drug to enter to body.
In a study of furanocoumarin, researchers from the University of North Carolina at Chapel Hill gave 18 healthy volunteers felodipine, a common blood pressure lowering medication. Some took the drug with orange juice, some with grapefruit juice, and the last group took the drug with grapefruit juice that had the furanocoumarins removed.
Researchers then measured the amount of medication in each patient's blood. They discovered that those who used the furanocoumarin-free grapefruit juice had the same amount of the drug in their blood as those who used orange juice. The patients who drank normal grapefruit juice, however, had up to a 420 percent increase in blood levels of felodipine at any one time. The results of the study are published in the American Journal of Clinical Nutrition.
"This is the best evidence to date that furanocoumarins are the active ingredients in grapefruit juice that cause the interaction with medications," said Dr. Paul Watkins, lead study author.
According to researchers, identifying this chemical could lead to identifying other foods with furanocoumarins that may cause drug interactions. Also, for drugs that do not enter the body easily, furanocoumarins may be added to the pills to help them be absorbed by the intestine. Additionally, by removing this substance from grapefruit juice, it may be possible to create commercially available grapefruit juice without the medical concerns.
"The interaction between grapefruit juice and certain medications is certainly a hot topic," says Ellen Guthrie, Pharm.D. "These include calcium channel blockers - such as Plendil and Procardia - which are often prescribed for high blood pressure; Sandimmune, a drug given to people who have had organ transplants; sedatives, such as Xanax and Valium; and many herbal medications. Some other classes of drugs, including steroids, painkillers and antihistamines, may also interact with grapefruit juice. Interestingly, a few studies have actually focused on the effects of daily grapefruit juice intake as a means to reduce the need for medication. While this is never advised without prior consultation with your doctor, it does seem to be gaining popularity"
Wow.
