The Food and Drug Administration has expanded its nationwide recall of certain Lipitor products, trying to track down counterfeit versions of the drug. The expanded recall involves products repacked by Med-Pro Inc., of Lexington, Neb., and distributed by Albers Medical Distributors Inc., of Kansas City, Mo.

The came as researchers found the Pfizer, Inc. drug helps reduce strokes and heart attacks in patients with Type II diabetes.

The FDA said the action is part of its continuing investigation into the counterfeiting of the popular drug. Officials said the FDA's Forensic Chemistry Center in Cincinnati has determined the counterfeit tablets tested so far do, in fact, contain the chemical atorvastatin, the active ingredient of Lipitor.

The analysis has not identified any harmful substances in the counterfeit tablets, although analytical testing continues, the FDA said.

Patients who have any Lipitor bottles labeled as "Repackaged by: MED-PRO, Inc.; Lexington, NE 68850" should not take the medication and should instead return it to their pharmacy.

Lipitor blocks the body's ability to produce cholesterol, thus preventing or reducing the harmful build-up of plaque in artery walls that contributes to heart disease, stroke and other maladies. Lipitor is among the best-selling pharmaceuticals ever developed.

Clinical Trial Stopped

So successful was Lipitor in preventing strokes and heart attacks in patients with type II diabetes that a four-year clinical trial was halted mid-stream so that all patients in the study could begin taking the drug, Pfizer announced.

The trial included 2,800 diabetes patients in the United Kingdom and Ireland with no history of heart disease or stroke. Diabetics are at high risk of cardiovascular problems because the high levels of blood sugar that accompany diabetes can damage blood vessels.

Halting a clinical trial in midstream is unusual but not unprecedented. It occurs when a drug or treatment is so clearly effective that it would be unethical to allow others in the trial to continue taking a placebo or another drug.

Another trial of Lipitor, involving patients with normal or slightly elevated cholesterol levels, was halted late last year when patients taking it had fewer fatal coronary incidents and non-fatal heart attacks than patients receiving placebos.