Drug maker Merck said that studies had shown that the drug, introduced in the U.S. in 1999 and also used to treat acute joint pain, could double the chances of a heart attack or stroke.

And the quick turn of events had patients, doctors and pharmacists in Greater Cincinnati and Northern Kentucky scrambling for information.

"My first patient of the day told me about it, that's how I initially learned of this," said Dr. Michael Luggen, professor of clinical medicine at the University of Cincinnati and an arthritis specialist at University and Christ hospitals. "I've never seen this before. This is a useful drug, and it will be difficult in some cases to find an early replacement."

Owners and pharmacists at several area pharmacies said they had yet to receive official word or instruction from the Whitehouse Station, N.J.-based drug maker as late as Thursday evening, but had stopped dispensing the drug based on news reports.

VIOXX RECALL

• Why the drug is being pulled. A study by Vioxx maker Merck Co. that tested the arthritis drug's possible use in combating colon polyps revealed the risk of heart attack or stroke doubled compared to people taking a dummy pill. • What you should do. If you've been taking Vioxx, the maker advises you to stop taking it immediately and consult your doctor for possible alternative medications. • Impact on Merck. Sales of competing arthritis pain relievers are expected to rise sharply. On Wall Street Thursday, Merck stock lost 26.8 percent of its value to close at $33. • Answers to more of the questions consumers might have.

"We're telling them to contact their physicians, but right now, reporters know more than we do," said Jerry Durr, pharmacist at Blank's Pharmacy in Covington.

Most pharmacists and doctors also said Thursday that they were telling patients to stop taking the drug, even if they had doses left at home.

But Jeannine Gallenstein of Richwood said she was thinking twice before taking that advice.

"I've tried everything else, and Vioxx is the only thing that works," said Gallenstein, who started taking the drug two years ago after knee surgery. "I went through all the other alternatives before I got to this. And you better believe I'm tempted to take the rest of my bottle; I've got 23 pills left. This is expensive stuff - I nearly lost one pill just yesterday and that would have cost me the $15 co-pay per dose."

Refunds available

Merck said about 2 million people worldwide use Vioxx, and a total of 84 million have taken it since it came on the market with great fanfare in 1999. The company said that it would refund patients for unused drugs, as long as the doses were returned in original packaging.

No local usage figures were available, but area pharmacists said it was pretty much tied with rival drug maker Pfizer's Celebrex as the top severe arthritis pain drug sold.

News of the drug's dangers came from a three-year study aimed at showing that Vioxx could prevent the recurrence of polyps, which can turn cancerous, in the colon and rectum. Merck stopped the study after discovering study participants had double the risk of a heart attack, compared to others taking dummy pills.

The company said the heart risks and other cardiovascular complications appeared 18 months after patients started taking Vioxx.

"We're taking this action because we believe it best serves the interest of patients," Ray V. Gilmartin, Merck's chairman, president and chief executive, said in a prepared statement.

Label change in 2001

A previous study three years ago had shown that the possibility of such risks existed, but that study found that the risk increased in the first 90 days of Vioxx treatment.

Merck quickly was able to discount that study but the Food and Drug Administration still required a warning about heart attacks be put on the drug's label in 2001.

"This is not a total surprise," said Dr. Steven Galson, acting director of the FDA's Center for Drug Evaluation and Research.

Officials don't know yet how the drug may be causing the increased risk.

One thing that was certain Thursday, however, was the reaction of Wall Street.

"It's a disaster for Merck, coming at the worst time," said independent health care analyst Hemant Shah of HKS & Co. in Warren, N.J., noting that the patent on another key Merck drug is set to expire soon.

Vioxx is one of Merck's most important drugs, with $2.5 billion in sales in 2003. But sales dipped 18 percent in the second quarter of this year to $653 million, partly due to increasing concerns about the drug's safety.

Merck, the world's third-biggest drug maker, announced the news before the stock market opened Thursday, saying the Vioxx recall will slash about 50 cents to 60 cents a share from its earnings for the rest of this year - previously the company expected earnings of between $3.11 and $3.17.

At the end of trading, the company's shares plunged $12.07, or 26.8 percent, to close at $33.14 on extremely heavy trading, losing $28 billion in market value.

Dr. Joel Reginelli, a cardiologist at the Cardiology Center of Cincinnati, and other experts said some of the uncertainty swirling around the announcement is whether the problems are caused just by this drug or by all drugs in its class, known as COX-2 inhibitors. The primary drugs in this class are Celebrex, Vioxx and Bextra, a successor to Celebrex that also is made by Pfizer.

"There is just not enough information right now to make that call," said Dr. Cathy Rosenbaum, clinical effectiveness and safety officer for Bethesda North Hospital. "This also could just be the dose involved with Vioxx."

UC's Luggen also noted that about 10 percent of patients were allergic to ingredients in the Pfizer drugs, making replacements difficult.

Reginelli said he wasn't taking any chances.

"My mom takes Celebrex, and I told her to stop for the time being," he said. "I personally feel that this will eventually extend to the entire class of drugs."

The Associated Press contributed to this report. E-mail jpilcher@enquirer.com