Plavix Warnings Over Use With Heartburn Drugs Updated in Canada

Canadian health officials are easing label warnings on Plavix about the potential interactions with heart burn drugs, indicating that recent findings suggest that not all of those drugs decrease the blood thinner’s effectiveness, as was previously thought. 

In 2009, label warnings were added to Plavix in Canada that suggested the effectiveness of the blood thinner could be reduced when used together with heart burn drugs that are part of a class of medications known as proton pump inhibitors (PPIs), which could put patients at risk for serious and potentially life-threatening side effects.

Last week, on September 22, Health Canada issued a press release saying that new evidence now shows that not all PPIs have a negative impact on Plavix.

Recent studies found that some PPIs, such as Prilosec (sold as Losec in Canada), can strongly or moderately reduce the effectiveness of Plavix. However, others, such as Protonix, do not interact as strongly.

Plavix (clopidogrel) is prescribed to prevent blood platelets from sticking together to form clots. It is often prescribed to reduce the risk of heart attacks, strokes and blood clotting when drug coated stents are used in patients with arteriosclerosis and in other at-risk patients. It is a blockbuster medication, generating more than $6.5 billion in U.S. sales for Bristol Myers Squibb Co. and Sanofi-Aventis in 2010.

In the United States, there are a number of Plavix lawsuits pending against Bristol Myers Squibb Co. and Sanofi-Aventis that allege the drug makers heavily promoted the expensive medication without adequately researching the potential side effects of Plavix, which some studies suggest may actually provide no benefit over taking a four-cent-a-day aspirin.

Plaintiffs allege that they suffered injuries as a result of their unnecessary use of Plavix, such as gastrointestinal bleeding, severe ulcers and a rare blood disorder known as TTP, or thrombotic thrombocytopenic purpora. Some complaints also allege that Plavix did not provide the promoted benefit of reducing the risk of a heart attack or stroke, raising questions about the effectiveness of Plavix among some users.

In November 2009, the FDA issued a public health advisory warning that side effects of Prilosec may interfere with Plavix effectiveness, increasing the risk of heart attack, death or other injuries for patients.

In March 2010, a Plavix “black box” warning was added to alert patients and healthcare professionals that the anti-clotting drug may not work in some patients due to genetics. The FDA indicated that a genetic test is available to determine whether patients are able to metabolize Plavix efficiently and suggested that doctors should consider another medication for at-risk patients who are confirmed to have the gene variant.