Pfizer Inc is interested in selling a non-prescription version of its Lipitor cholesterol drug after it loses U.S. patent protection, but would likely face a battle with regulators because of safety concerns, the Wall Street Journal reported on Wednesday.

The report, citing people familiar with the matter, said Pfizer is hopeful that regulators will allow an over-the-counter form of Lipitor. It would help Pfizer squeeze new sales out of Lipitor once the nearly $11 billion-a-year drug begins facing competition from generic prescription forms of the medicine in November, the Journal said.

The report said rival drugmaker Merck & Co in recent years failed to convince the U.S. Food and Drug Administration to allow it to sell an over-the-counter version of its older Mevacor cholesterol drug.

Mevacor, Lipitor and other top-selling cholesterol fighters belong to a class of medicines called statins that can cause liver and muscle damage in a small percentage of patients.

Pfizer spokesman Ray Kerins declined to comment on the report, when asked by Reuters, but said Pfizer has strategic plans in place for Lipitor's loss of exclusivity.

(Reporting by Ransdell Pierson. Editing by Robert MacMillan)

Pfizer Merck & Co.