Genetic test for Plavix use may be unneeded: study

December 29, 2011

A new study published Wednesday cast doubt on the usefulness of a genetic test for patients taking the anti-coagulant drug Plavix, calling into question last year's FDA warning about the blood thinner.

The study, a new review of 32 previous clinical studies published in the , said the genetic test may not help identify those patients more at risk of a heart attack or other cardiac event.

Plavix, one of the world's top selling drugs, is marketed by US-based Bristol-Myers Squibb and France's Sanofi. It reduces the risk of heart attack and stroke by keeping from sticking together to cause clots.

In 2010, the US Food and Drug Administraion ordered the manufacturers to add a boxed warning to Plavix packets saying the drug may be less effective in preventing heart attacks in people who cannot metabolize it properly.

The FDA said an estimated two to 14 percent of the US population are poor metabolizers who have a certain variant of the gene that makes the CYP2C19 , which converts Plavix to its active form.

The FDA had recommended that doctors prescribe higher doses of Plavix, or clopidogrel, to those patients who had the genetic test and were found not to produce enough of the enzyme.

But researchers led by Michael Holmes at University College London concluded after their new review of studies involving 42,000 patients that those with the did not have more than other patients.

"Despite associations between CYP2C19 genotype, clopidogrel metabolism, and platelet aggregation, this systematic review and meta-analysis does not demonstrate a clinically important association of genotype with ," researchers led by Michael Holmes at University College London said.

The only notable possible exception was in patients with stent thrombosis, they wrote.

"The FDA's warnings on Plavix were premature and were not based on solid science," said Steven Nissen, a cardiologist at the Cleveland Clinic Foundation, in an editorial published in the Journal of the AMA.

Plavix sales totalled $5.4 billion in the first three quarters of 2011, as compared with $4.9 billion in the same period last year.

About 40 million people take the drug worldwide.

Explore further: Analysis does not support genetic test before use of anti-clotting drug

Related Stories

Analysis does not support genetic test before use of anti-clotting drug

December 27, 2011
Although the U.S. Food and Drug Administration (FDA) has recommended that a certain type of genetic testing (for the genotype CYP2C19) be considered before prescribing the drug clopidogrel to identify individuals who may ...

Recommended for you

In most surgery patients, length of opioid prescription, number of refills spell highest risk for misuse

January 17, 2018
The possible link between physicians' opioid prescription patterns and subsequent abuse has occupied the attention of a nation in the throes of an opioid crisis looking for ways to stem what experts have dubbed an epidemic. ...

Patients receive most opioids at the doctor's office, not the ER

January 16, 2018
Around the country, state legislatures and hospitals have tightened emergency room prescribing guidelines for opioids to curb the addiction epidemic, but a new USC study shows that approach diverts attention from the main ...

FDA bans use of opioid-containing cough meds by kids

January 12, 2018
(HealthDay)—Trying to put a dent in the ongoing opioid addiction crisis, the U.S. Food and Drug Administration on Thursday slapped strict new restrictions on the use of opioid-containing cold and cough products by kids.

Taking ibuprofen for long periods found to alter human testicular physiology

January 9, 2018
A team of researchers from Denmark and France has found that taking regular doses of the pain reliever ibuprofen over a long period of time can lead to a disorder in men called compensated hypogonadism. In their paper published ...

Nearly one-third of Canadians have used opioids: study

January 9, 2018
Nearly one in three Canadians (29 percent) have used "some form of opioids" in the past five years, according to data released Tuesday as widespread fentanyl overdoses continue to kill.

Growing opioid epidemic forcing more children into foster care

January 8, 2018
The opioid epidemic has become so severe it's considered a national public health emergency. Addiction to prescription painkillers, such as oxycodone and morphine, has contributed to a dramatic rise in overdose deaths and ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.