NEW YORK (CNNMoney.com) - Pfizer could use a new blockbuster and the sleeping pill industry could use a new drug, and both could happen this summer if the FDA approves Indiplon at its review later this month.

Pfizer (up $0.21 to $25.43, Research), the biggest drugmaker in the world, and partner Neurocrine Biosciences (up $1.13 to $54.40, Research) are eagerly awaiting the Food and Drug Administration's decision on Indiplon, to be announced as early as May 15. There are three possible scenarios: the FDA could approve the drug, shoot it down, or send it back to the drawing board with an "approvable" letter, meaning that it needs more work.

"I continue to expect the product to be approved on the FDA PDUFA date," said Bernstein analyst Geoff Porges, using the agency's drug review term. "I don't see any significant safety concerns and the product's efficacy seems pretty clear."

But it's not all up to the FDA. Sleeping pills also need a classification from the Drug Enforcement Agency, which is expected to classify Indiplon as a schedule IV drug. This means it would share the same classification as addictive sedatives such as Xanax, produced by Pfizer, and Valium from Roche.

While the FDA provides dates on when it expects to announce drug approvals or non-approvals, the DEA leaves everyone in the dark. A DEA spokeswoman said her agency does not give dates for when it plans to announce drug classifications.

Analysts see Indiplon as a potential blockbuster that could enter the market this summer, if the FDA gives it the green light and the DEA doesn't sit on it for too long. Les Funtleyder, analyst for Miller Tabak, projects peak sales of $1.2 billion for Indiplon by 2009, while Bernstein analyst Porges said sales could peak at $2 billion by 2011 or 2012.

The sleeping pill market in the U.S. is expanding, as stressed-out Americans rely heavily on pharmaceuticals to help them calm down. The market has also been driven by direct-to-consumer advertising, which soared to $345 million in 2005, nearly six times its 2004 level, according to TNS Media Intelligence, an advertising research firm.

"We live in a stressed-out society and people want to go to sleep," said Funtleyder. "Sleeping is the new sex."

Merck (up $0.02 to $34.33, Research), the number 2 U.S. drug maker, is also testing a sleeping drug, Gaboxadol. The drug is currently in late-stage testing and has not been filed with the FDA.

Indiplon could be entering the market at an opportune time, because its biggest potential rival, Ambien, a sleeping pill from the French drugmaker Sanofi-Aventis (down $0.52 to $48.43, Research), will lose patent protection within months.

In addition, researchers from the University of Minnesota Medical School and the Mayo Clinic recently found that Ambien causes some people to gorge on high-calorie food while sleeping in the middle of the night, and there have also been reports of sleep-driving and sleep-sex, with no memory of it afterwards.

"It seems as though this so-called somnambulism affects a small number of patients and has not been seen with the newer drugs like Lunesta and Indiplon," said Amusa.

Lunesta, the No. 2 sleeping pill from Sepracor (up $0.83 to $45.92, Research), would be Indiplon's chief competitor. Sepracor spent $215 million advertising Lunesta in 2005, and by now most people have probably noticed the commercials with the glowing, fairy-like butterfly that makes pillow-side visits to insomniacs. Analysts see Lunesta as a potential blockbuster.

Another competitor, Rozerem from the Japanese company Takeda Pharmaceutical, is the world's first non-addictive sleeping pill. Rozerem might be a healthy alternative to its addictive counterparts, but that's actually hurt sales, according to a recent interview with Bernstein analyst Gbola Amusa, who projects $300 million in annual revenue by 2010.

The analysts interviewed for this story do not own shares of stock in the companies mentioned here.

To read about Pfizer's first quarter earnings, click here.