LITTLE ROCK, Ark. (AP) - Wal-Mart Stores Inc., the world's largest retailer, announced Monday it would expand its discounted prescription drug program to offer 90-day supplies for $10 and add several women's medications at a discount. It also said it would lower the price of more than 1,000 over-the-counter drugs.

The move marks the third phase of a company program that began in 2006 and has saved customers more than $1 billion, Wal-Mart said.

With the expansion, the company began filling prescriptions Monday for up to 350 generic medications at $10 for a 90-day supply at Wal-Mart, Neighborhood Market and Sam's Club pharmacies in the U.S.

In addition, the company will add several women's medications to its list of prescriptions available for $9, including drugs to treat breast cancer and hormone deficiency.

For instance, alendronate, the generic version of osteoporosis medication Fosamax, will be added to the list. Company pharmacies will fill 30-day prescriptions of alendronate for $9 and a 90-day supply for $24 at a comparison of $54 and $102, respectively, that women previously paid for the same amounts, the company said.

Tamoxifen, used to treat breast cancer, will be offered for $9 for a 30-day supply, as well combination estrogen/methyltestosterone tablets, prescribed for menopause and hormone deficiency.

Wal-Mart also will lower the prices of more than 1,000 over-the-counter medications to $4 or less in its pharmacies, company officials said. The over-the-counter medication price rollbacks represent about one-third of the retailer's over-the-counter medicines.

Since 2006, Wal-Mart's $4 generic drug program has expanded to every state, except North Dakota, where Wal-Mart has no in-store pharmacies. And many company competitors have followed the retailer's lead.

While stressing that the expansion was designed to help customers at a time of exorbitant health-care costs and difficult economic times, Wal-Mart senior vice president John Agwunobi said the program has worked in everyone's favor.

"This is the time for us now to begin building capacity," he said. "It offers (customers') employers potential savings. It offers the customers significant savings. It also offers us the ability to add capacity to our pharmacies without adding people."

Shares of Wal-Mart fell 59 cents to $56.91 in morning trading Monday.

(Copyright 2008 by The Associated Press. All Rights Reserved.)