• January 3, 2008

The U.S. Food and Drug Administration has given approval for Ohm Laboratories Inc. to sell generic versions of Pfizer Inc.'s Zyrtec antihistamine without a prescription. The popular drug generated about $1.3 billion in annual sales for Pfizer, but lost patent protection in late December.

Princeton, N.J.-based Ohm will begin selling the drug immediately under its chemical name, cetirizine hydrochloride, in 5- and 10-milligram doses. Ohm, which sells generic, private label and nonprescription medicines in the U.S., is a subsidiary of Ranbaxy Laboratories Ltd., India's biggest drug company.

The FDA last week approved two other companies to sell cetirizine hydrochloride as a generic, over-the-counter drug. They are Detroit-based Caraco Pharmaceutical Laboratories Ltd. and Perrigo Co. of Allegan, Mich. Perrigo will sell the products under store-brand labels.

Fort Washington, Penn.-based McNeil Consumer Healthcare, a unit of Johnson & Johnson, said in November that it had won approval to start selling brand-name Zyrtec over the counter in January. It acquired the "switch rights" to sell a nonprescription version of Zyrtec as part of its $16.6 billion purchase of Pfizer's consumer health-care business at the end of 2006.

--Tanya Irwin