Procter & Gamble Co. said Friday that its biggest product launch of the year is already under way, and consumers can expect to see the highly anticipated, over-the-counter version of the heartburn medication Prilosec on store shelves Monday.

That, despite a federal lawsuit filed this week by Johnson & Johnson-Merck, disputing P&G's claim that Prilosec eliminates heartburn for a full day with a single pill.

Johnson & Johnson-Merck markets competing over-the-counter drugs Pepcid AC and Mylanta.

"We expected this, but it hasn't changed our plans,'' said Greg Allgood, a spokesman for P&G. "Our claims are absolutely true and are consistent with the FDA approval of Prilosec OTC.''

P&G is putting 1,200 trucks on the road to deliver the medicine simultaneously at midnight Sunday. The Cincinnati-based giant has spent $100 million to advertise and promote Prilosec OTC for drug maker AstraZeneca.

P&G's retail customers - including Cincinnati-based Kroger Co. - won't be be allowed to take shipment of Prilosec "one minute before the stroke of midnight'' Sunday, Allgood said.

P&G has projected first year sales of up to $400 million Prilosec, which would top any product rollout by any packaged-goods company - ever.

Randy Tucker