The agency reviewed the issue after the drugs' manufacturer, AstraZeneca, sent regulatory officials a preliminary analysis of two small studies in May that suggested the possibility of a risk.
Those studies compared treating the chronic heartburn known as gastroesophageal reflux disease, or GERD, with drugs or surgery. The company's initial analysis counted more patients treated with drugs who had heart attacks, heart failure or heart-related sudden death.
The FDA followed up on those studies, and found that they seemed skewed: Patients who underwent surgery were younger and healthier than those treated by drugs, suggesting the heart link was a coincidence.
The agency then looked at 14 additional studies of the drugs, and found no evidence of heart risks. In fact, in a few studies where patients received either medication or a dummy pill, those who took the heartburn drugs actually had a lower incidence of heart problems.
The FDA plans to complete its probe within three months, but issued a public notice Thursday that it "does not believe that health care providers or patients should change either their prescribing practices or their use of these products at this time."