NEW YORK (AP) -- Two million starter kits of the first over-the-counter weight loss pill approved by federal regulators were sold in the five months since it first hit shelves, GlaxoSmithKline said Monday. The figure was in line with the drugmaker's expectations. Alli, which hit shelves in June, is the only nonprescription weight loss drug approved by the Food and Drug administration.

Glaxo, based in the U.K., is set to officially announce the pill's sales figures Tuesday, ahead of its earnings report on Wednesday.

While it's too early to tell how many consumers will continue using the drug, feedback on the drug's Web site myalli.com so far has been overwhelmingly positive, said Joe Cadle, marketing director for Glaxo Consumer Healthcare. The pharmaceutical company expects to sell between 5 million and 6 million kits annually, translating to at least $1.

5 billion in annual retail sales. "Clearly given the overweight and obesity numbers in this country, (alli) can have a long-term, sustainable business," said Malesia Dunn, a company spokeswoman. Two-thirds of the U.

S. population is estimated to be overweight or obese. A body mass index over 30 is considered obese.

Labeling indicates alli is appropriate for anybody who is overweight, or has a body mass index of 25 or higher. The drugmaker ran into trouble earlier this summer, when a report found its widely prescribed diabetes pill raised the risk of heart attacks and possibly death. In August, Glaxo agreed to label the drug, Avandia, with severe "black box" warnings about a risk of heart failure to some patients.

Glaxo is banking on alli to become a major drug in its portfolio. The company is spending $150 million on marketing the drug this year, making it one of the drug maker's biggest campaigns to date. Alli comes in "starter kits" containing a food journal, a healthy-eating guide and a fat and calorie reference guide.

A 60-capsule kit costs about $50 while a 90-capsule pack costs about $60. Analysts say alli's long-term success will hinge on Glaxo's ability to convince people that diet pills aren't a magic bullet. Failing to do so could lead to disappointment and poor sales.

"If (the marketing is) done correctly, it has to be a long and drawn out campaign," said Steve Brozak, an analyst with WBB Securities. Glaxo's understated campaign so far is a good sign, Brozak said. But he added that there's no way to truly gauge the financial success of the drug so soon after its release.

One of the pitfalls encountered by the prescription version of the drug, Xenical by Roche Holding, was the drug's unpleasant side effects, such as leakages and oily discharges. Xenical contains twice the dosage of alli. About half of patients in clinical trials for alli experienced similar gastrointestinal side effects.

GlaxoSmithKline is frank about the side effects, which it says can be controlled if the drug is used properly. The campaign stresses the importance of keeping meals under 15 grams of fat to avoid effects. Educational materials even recommend people start the program when they have a few days off work, or to bring an extra pair of pants to the office.

Glaxo has made it a point to ensure the "right person is choosing (alli) at the right time," Cadle said. The sales figures were to be officially released Tuesday, with the launch of a new ad campaign for the drug. The campaign will feature first-person accounts from 100 users who were recruited by the company to take the drug for free prior to its launch.

In clinical trials, the FDA says that people using alli lost an additional 2 to 3 pounds for every 5 pounds lost through diet and exercise. When taken with meals, the drug blocks the absorption of about one-quarter of any fat consumed. That fat -- about 150 to 200 calories worth -- is passed out of the body, potentially resulting in loose stools.

FDA: http://www.fda.gov (This version CORRECTS ADDS company comment, background on Avandia.

corrects byline style. 'alli' is cq.