Federal regulators have opened a safety investigation of two popular heartburn drugs - Nexium, marketed as the "purple pill," and Prilosec, its older chemical cousin - after receiving clinical data that appeared to link them to serious heart problems.
But the Food and Drug Administration said Thursday that it has found no firm evidence of such a connection, and it advised doctors and patients not to make any changes. The agency promised a more complete answer within three months.
"At this time, FDA's preliminary conclusion is that collectively these data do not suggest an increased risk of heart problems," an agency statement said.
The data was supplied to the FDA and drug regulators in other countries by AstraZeneca, maker of both medications. In a statement, the company said that based on all the data available, Prilosec and Nexium "are not associated with an increased risk of cardiac events."
Nonetheless, the FDA said it was notifying the public in keeping with efforts to foster greater openness at the agency, which has been criticized for keeping a lid on problems with painkillers, antidepressants and, most recently, the heart risks of the diabetes drug Avandia.
Nexium was the sixth most commonly prescribed brand-name drug last year, according to Drug Topics, a Web magazine.