(Newser) – For the first time in 13 years, the FDA has approved an anti-obesity pill. The medication, called Belviq, targets a section of the brain responsible for regulating hunger, reports Bloomberg. Sales could hit $2 billion in 2020, predicts an analyst. “Two-thirds of the people in this country are overweight or obese,” he says. "It's an enormous opportunity." The drug is expected to be on the market in early 2013, notes AP.

Belviq will be available only to patients with a body mass index of 30 or higher, or to patients with a BMI of 27 or higher if they suffer from weight-related illnesses such as type 2 diabetes, reports CBS News. Three studies showed participants shed 3% more body weight on Belviq than participants taking a placebo. The stock price of Arena Pharmaceuticals, the San Diego-based company that created the pill, surged 29% after the news broke. (Read more medication stories.)

