Wal-Mart said Thursday it is expanding its $4 prescription program to include 24 new drugs and adding $9 birth control and fertility drugs to the list.

Rival Target quickly followed suit.

“Consistent with our long-standing practice to be price competitive with Wal-Mart, Target will match Wal-Mart’s addition to their $4 generic drug program. In addition, Target will match Wal-Mart’s $9 generic drug pricing,” said Target spokeswoman Brie Heath.

The new $4 drugs treat such ailments as glaucoma, attention deficit disorder, fungal infections and acne.

The deeply discounted generic drug prices can represent a big discount from the name brand equivalent, Wal-Mart said.

Last month, anti-fungal Lamisil, for example, sold for an average price of $337 for a month’s supply, according to Wal-Mart. The generic equivalent, terbinafine, is now available at Wal-Mart, Sam’s Club and Neighborhood Markets for $4, saving prescription holders $333 a month, the mega-retailer said.

With the new additions, 361 generic prescription products are now available at a reduced price at the discounters.

Wal-Mart said since the $4 program was introduced in September 2006, 40 percent of the prescriptions filled at Wal-Mart, Sam’s Club and Neighborhood markets were for the $4 reduced price drugs. Wal-Mart estimated the combined customer savings nationwide on those prescriptions at $610 million.

The full list of drugs available on the reduced price prescription program is available at www.walmart.com/pharmacy or www.target.com/pharmacy.

Or shoppers can phone their nearest Wal-Mart pharmacy to determine if their medications are on the reduced price list, said Wal-Mart spokeswoman Stephanie Johnston.

Wal-Mart said with the addition of the new drugs, its low-cost program covers “most commonly treated medical conditions.”

But the National Community Pharmacists Association, which represents non-chain pharmacies that compete with Wal-Mart, called the discounts a publicity stunt that covers only a fraction of the 8,700 generic prescription drugs approved by the Federal Drug Administration.

Analysts have said the main benefit for Wal-Mart was in drawing more shoppers into its stores who may come for prescriptions and then make purchases in other departments.

Wal-Mart shares closed at $43.61 Thursday, up slightly.

Wal-Mart’s estimate of the $4 prescription drug program impact on Arizona:

* Saved customers an estimated $10.5 million in first year.

* Provides solution for more than 1 million uninsured residents.

* Will save the state’s Medicaid program “tens of thousands of dollars annually.”

* Lower cost option for 816,639 Medicare beneficiaries if they hit the “doughnut hole” gap in Medicare Part D coverage. That requires patients pay 100 percent of drug costs after first $2,400 until ceiling of $5,421 is reached.