Pfizer said Thursday that it would provide 70 of its most widely prescribed drugs, including Lipitor and Viagra, free to people who have lost their jobs and health insurance.

The company said it would give away the medicines for up to a year to Americans who lost jobs since Jan. 1 and had been taking the Pfizer drug for three months or more.

The move could earn Pfizer some good will; it has long been a target of critics of drug industry prices and sales practices. The program might also help keep those patients loyal to Pfizer brands.

Officials for Pfizer, which is based in New York, said they did not know how much the program would cost and had not put a cap on spending for it.

The drugs covered in the program include several for diabetes and some of Pfizer’s top money makers, including the painkiller Celebrex and the fibromyalgia treatment Lyrica. Drugs from several other classes like antibiotics, antidepressants, antifungal treatments, heart mediations, contraceptives and smoking cessation products are also included. Cheaper generic versions are available for many of the drugs.

Starting Thursday, patients can call a toll-free number, (866) 706-2400, to sign up. Those whose drugs are not included in the program will be referred to other company aid programs. Starting July 1, patients can also apply through the Web site, www.PfizerHelpfulAnswers.com, which has information about the other Pfizer aid programs. Applications will be accepted through Dec. 31.

Many drug makers, including Pfizer, have been raising prices, partly to offset declines in revenue as the recession reduces the number of prescriptions people can afford to fill.