When drugs are being reviewed by regulators, they are assessed for what risks they might pose to consumers. Those risks, once identified, can be dealt with in one of three ways: They can be designed out of the drug through a reformulation or the use of new excipients, consumers can be made aware of the risk through labeling, or consumers can be restricted from accessing the drug in an attempt to mitigate the risks.
But what if a fourth option-the elimination of the risk outside of the drug-was available?
That's one takeaway from recent research conducted by University of Florida researchers, who wrote in December 2012 that they had pinpointed the compounds in grapefruit responsible for causing dangerous interactions with dozens of drugs, and have recently announced that they successfully bred a new type of hybrid grapefruit that does not contain those compounds.
The US Food and Drug Administration (FDA) regularly sends out warnings about the interactions, in which it notes that drinking grapefruit juice or otherwise consuming grapefruit can cause an increased rate of drug absorption in the blood stream. This can cause adverse events by causing higher concentrations of the consumed drug.
"Many drugs are broken down (metabolized) with the help of a vital enzyme called CYP3A4 in the small intestine," FDA explained in one such missive. "Certain substances in grapefruit juice block the action of CYP3A4, so instead of being metabolized, more of the drug enters the bloodstream and stays in the body longer. The result: potentially dangerous levels of the drug in your body."
In other drugs, grapefruit actually has the opposite effect, resulting in a reduced dose that can affect the consumer in other negative ways. This occurs because of the same blocking mechanisms, FDA explained.
It's a relatively common side effect as well, with the interactions affecting many statin, blood pressure, organ transplant rejection, anti-anxiety, anti-arrhythmia and antihistamine drugs. Combined, those drugs are taken by tens of millions of consumers in the US and around the world.
The benefits to consumers could be substantial, but only if the new type of grapefruit is widely commercialized. Reuters noted that the UF researchers said commercialization of the grapefruit could be five to seven years away.
But in addition to the benefits of taste-the new variety is reportedly sweeter and juicier than previous varieties-it could have regulatory impacts as well.
"FDA has required some prescription drugs to carry labels that warn against consuming grapefruit juice or fresh grapefruit while using the drug," FDA explained in a brochure on the fruit's interactive effects. "[T]he agency's current research into drug and grapefruit juice interaction may result in label changes for other drugs as well."
It's conceivable then that if the new variety gains widespread acceptance that FDA and drug sponsors might one day soon have one less thing to worry about during the regulatory and postmarketing surveillance phases of a product's lifecycle.
Until then, drink safely.