Erie County has filed a lawsuit against Merck & Co., the maker of the prescription drug Vioxx, alleging that the pharmaceutical maker defrauded the Medicaid program of an estimated $6 million.

In papers filed in New Jersey, where Merck is based, attorneys for Erie County say the company engaged for many years in an aggressive and fraudulent marketing campaign, targeted toward both the medical profession and consumers, that was designed to minimize the dangers of Vioxx and convince physicians to write prescriptions for the drug that they would not have written had they known the truth.

The county said in a news release that Vioxx was sold as a painkiller for treating arthritis, headaches and other conditions, and was many times more expensive than over-the-counter pain relievers like naproxen, sold as Aleve, and ibuprofren, or Advil. The complaint said Merck had evidence of cardiovascular risks associated with Vioxx before it ever sold the drug to the public. The county refers to a study, sponsored by Merck, that showed that patients who took Vioxx had five times the risk of having a heart attack, compared with those taking naproxen.

Despite the results of this study, Merck failed to warn of these adverse consequences and continued to conceal or minimize the dangers of Vioxx in order to promote sales.

Merck withdrew Vioxx from the market in September 2004.

New York state, along with at least six other states, has filed similar actions against Merck. The company has defended its actions, saying it carefully studied Vioxx before and after receiving U.S. Food and Drug Administration approval, and consistently made the results of those studies available to the FDA and to the medical and scientific communities.