First came the negative publicity, then the lawsuits.

Merck & Co. and Schering Plough Corp., makers of the cholesterol-lowering combination drug Vytorin, are getting hit with a wave of lawsuits asserting the companies knew its product didn't work and delayed telling the public about it.

At least 10 lawsuits have been filed in federal courts, with half the filings in New Jersey, where both parent companies are based. Other federal suits have landed in California, New York, Ohio and Colorado.

The drugmakers "reaped billions of dollars in profits" by failing to release negative results, asserted a class-action complaint filed by a Philadelphia firm on behalf of Lionel D. Galperin of Washington state. The companies also caused patients to spend more money on Vytorin, which sells for more than $100 for 30 pills, compared with a lower-cost generic, the suit alleges.

Skip Irvine, spokesman for the Merck-Schering Plough partnership, said the companies would vigorously contest the suits. The company has stopped its usual television advertising for the drug, opting to place full-page ads in publications, including The Inquirer, defending the drug's safety and efficacy.

Vytorin is composed of two drugs: Zetia, which blocks cholesterol absorption in the stomach, and Zocor, a traditional statin that lowers cholesterol production in the liver. Sales of both drugs totaled $3.8 billion in 2006, up from $2.4 billion in 2005, according to Merck's government filings.

The drugmakers aren't the only ones facing scrutiny.

Both the American College of Cardiology, which represents most cardiologists, and the American Heart Association echoed the companies' assurances and urged patients on Vytorin not to panic after a major test of Vytorin was released on Jan 14.

But their stands have drawn criticism from congressional investigators and others because both groups take in substantial sums from pharmaceutical firms.

Daniel W. Jones, the heart association's president, acknowledged the industry's support but maintained it had not driven the group's professional advice.

He said the organization received $48.2 million last year from pharmaceutical and medical device firms - or about 6 percent of the group's $799 million annual budget.

He also noted that the association's guidelines call for a statin to be first-line treatment and that alternatives like Vytorin should be used only when statins fail or cannot be tolerated.

W. Douglas Weaver, president-elect of the cardiologists, echoed those concerns. "We really had huge numbers of patients calling physicians' offices and not knowing how to interpret this information," Weaver said. "People were discontinuing statins because of the confusion."

Weaver said he did not know how much of the group's $84 million budget comes from industry.

The House Committee on Energy and Commerce and the Senate Finance Committee want an accounting of the groups' links to industry.

"The public places great trust in the official views of the AHA and the ACC, so it is important to verify that these views have not been compromised by a financial relationship with the pharmaceutical industry," Rep. John D. Dingell (D., Mich.) said in a statement released Thursday.

In 2002, the companies started a trial called Enhance to see whether Zocor or the Zocor-Zetia combination was better at preventing plaque buildup in the neck arteries.

The companies completed the study in April 2006 but did not release preliminary results until a press release was issued on Jan 14. That was more than a month after congressional investigators had written to company executives, asking about the delay and demanding documents.

The Enhance study showed that the combination drug failed to provide any benefit and even performed slightly worse than Zocor alone on its main target, plaque buildup in the neck arteries.

But the combination Vytorin also lowered levels of LDL, or bad cholesterol, better than Zocor alone, a measure long proven critical to lower heart-attack risk. That finding prompted many doctors to say it was premature to get off the drug at this point.

The study also was small, involving 720 patients with extremely high levels of cholesterol from an inherited form of heart disease.

In a news conference yesterday, John Jenkins, director of new drugs at the Food and Drug Administration, said it was too soon to draw any conclusions from the Enhance study. A more complete trial testing whether the drugs prevent heart attack and death will not be done until 2011.

But many doctors appear not to be waiting. The prescription-tracking firm ImpactRx of Mount Laurel, N.J., surveyed primary-care doctors in the past week and found that Vytorin had fallen from 15 percent of new cholesterol drug prescriptions to 5 percent.

Contact staff writer Karl Stark

at 215-854-5363 or kstark@phillynews.com.