The company which employs close to 1,000 people in Westport, Co Mayo, posted a profit of $249.4m, or 82 cents per share, in the third quarter compared with $249.8m (€194m), or 81 cents per share, a year earlier.
Allergan also said it was exploring a sale of its obesity business on falling sales of the only product in the unit.
Sales of Lap-Band fell 21% to $122.7m, while sales of most of Allergan’s products increased during the third quarter.
The unit accounted for about 4% of Allergan’s total revenue in 2011.
The company expects sales of $160m from its obesity intervention products unit for the full year. It sees total product net sales of between $5.69bn and $5.77bn.
US health regulators recently approved two weight loss drugs, after a gap of 13 years, underlining the pressure on the Food and Drug Administration to approve treatments for obesity as about two thirds of Americans are considered overweight or obese.
Lap-Band has an inflatable band placed around the stomach through a minimally invasive surgery, creating a pouch that limits or reduces food consumption.
Adjusting for charges that include restructuring, research and development, and amortisation of acquired intangible assets, the company earned $1.06 per share.
Revenue rose 6% to $1.4bn. Analysts were expecting a profit of $1.04 per share, excluding special items, on revenue of $1.43bn, according to Thomson Reuters.
Shares of the California-based company, which has a market capitalisation of $21.18bn dollars, closed at $91.64 on Friday on the New York Stock Exchange.