Procter & Gamble's (NYSE:PG) first-quarter earnings results are good enough to cure acid reflux. Thanks to help from new products such as the heartburn drug Prilosec, the stock moved to a three-year high this morning.

The consumer products giant earned $1.26 per share, up 21% from the year before. Net sales increased by 13%, and organic sales -- which exclude acquisitions, divestitures, and the foreign exchange impact -- were up 7%. What's more, gross margin increased by a significant 180 basis points, not including restructuring charges.

While most of the company's categories were strong performers, the Prilosec story is the most compelling. Several months ago, P&G took a chance by entering into a licensing agreement with the drug's original maker, AstraZeneca (NYSE:AZN). After a dosage and labeling adjustment, the FDA agreed to allow the companies to market Prilosec without a prescription.

The move did not sit well with competitors Johnson & Johnson (NYSE:JNJ) and Merck (NYSE:MRK), which suddenly saw stiff competition for Pepcid and other products. The two filed a lawsuit last month, accusing P&G of false advertising.

That didn't stop what is by all accounts an extremely successful Prilosec rollout. In today's conference call (transcript provided by CCBN StreetEvents), CEO A.G. Lafley called it " the obvious highlight of the quarter," which could have produced even stronger results. It sold "faster than anybody thought it would. So, we have a supply chain system that just isn't perfect."

What can we expect from the drug in the future? "We're all smiling here," Lafley said, "because there has been a lot of discussion about Prilosec potential over the last week, as you might imagine. We are not going to know until we get enough initial trials with enough heartburn sufferers and more importantly, until we get enough repurchase."

But the conference call seems to indicate that sales will likely be well above the initial estimates, as management is already looking at the $200 million to $400 million range for the first year alone.

That's a lot of purple pills.