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Warning over grapefruit health risk

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Grapefruit contains chemicals which can interact with certain prescription drugs
Grapefruit poses a potentially lethal health risk to increasing numbers of patients takingprescription drugs, experts have warned.

The fruit contains chemicals which can interact with certain drugs, making them more potent.

Adverse effects can include acute kidney failure, respiratory failure, internal bleeding and sudden death.

While it is well known that some patients should avoid grapefruit, or grapefruit juice, the list of drugs involved has risen sharply in recent years.

Between2008 and 2012 the number of medications with the potential to cause serious harm by interacting with grapefruit increased from 17 to 43, said scientists writing in the Canadian Medical Association Journal. Each year, more than six of these drugs on average were being made available to patients.

Dr David Bailey, from Lawson Health Research Institute in London, Ontario, and colleagues describedthe trend as "disturbing".

They wrote: "Unless healthcare professionals are aware of the possibility that the adverse event they are seeing might have an origin in the recent addition of grapefruit to the patient's diet, it is very unlikely that they will investigate it. In addition, the patient may not volunteer this information. Thus, we contend that there remains a lack of knowledge aboutthis interaction in the general healthcare community."

More than 85 drugs in total can interact with grapefruit, and of these 43 can have serious side effects, said the researchers. The list of danger medicines includes treatments for anxiety, depression, allergy, HIV infection, seizures, heart rhythm abnormalities and high cholesterol.

A modest single helping of grapefruit can have an effecteven if consumed hours before a drug is taken, said the scientists. Frequent exposure to grapefruit could make matters worse. Combining the cholesterol-lowering drug simvastatin with a 200 millilitre glass of grapefruit juice once a day for three days more than tripled its concentration level. Older people with a reduced ability to tolerate drug overdoses were at greatest risk.

"The currenttrend of increasing numbers of newly marketed grapefruit-affected drugs possessing substantial adverse clinical effects necessitates an understanding of this interaction and the application of this knowledge for the safe and effective use of drugs in general practice," the experts concluded.
http://news.uk.msn.com/health/warning-over-grapefruit-health-risk
CMAJ. 2012 Nov 26. [Epub ahead of print]Grapefruit-medication interactions: Forbidden fruit or avoidable consequences?
Bailey DG, Dresser G, Arnold JM.
The public generally considers natural products such as “health foods” and herbal remedies to be safe and beneficial. That these substances are largely unregulated contributes to the misconception that they are innocuous: patients don’t feel the need to tell their physicians that theyare using them, and physicians don’t routinely ask patients if they are taking them. Yet there is a potential for these products to alter the action of certain drugs, sometimes with adverse clinical effects. Natural products can “interact” with drugs by affecting the biological processes that regulate their metabolism and elimination. The family of enzymes known as the cytochrome P450s (CYPs)1 areheavily involved in the business of drug metabolism. Of its many subtypes, CYP3A4 is one of the most important; we will use it to illustrate how interactions between natural products and medications can occur. CYP3A4 has been estimated to at last partly oxidize 60% of all drugs to metabolites that are either less active or more readily excreted (or both). Its availability in the small intestine...