The agency said there is not enough data yet to determine if other drugs in the same family as Nexium and Prilosec -- which is sold over the counter by the generic name esomeprazole -- such as ...

Popular heartburn pill Prilosec is set for its over-the-counter rollout Monday, with Proctor & Gamble sending out a fleet of 1,200 delivery trucks to get the medication onto shelves.

The prescription version of Prilosec is the familiar, $4 purple capsule prescribed for heartburn, acid reflux and erosion of the esophagus that can occur in severe cases.

Over-the-counter versions of proton pump inhibitors include those sold under the brand names Prilosec, Nexium and Prevacid.

With over-the-counter Prilosec looming, the heat is on AstraZeneca to shift Prilosec patients to Nexium to retain its $6.6 billion heartburn franchise.

It said its review of the new safety data was continuing. Nexium is available only by prescription, while Prilosec is sold over the counter by Procter & Gamble Co. .

Competitors to over-the-counter Prilosec include Pepcid AC and Pepcid Complete, both from a joint venture between Johnson & Johnson and Merck & Co., and Zantac 75 from Pfizer.