"The pain was so severe. I couldn't go to the mailbox. I couldn't go to church," Wolfe said, sobbing as she recounted how for months dentists and doctors were unable to find a cause for her pain.

Wolfe is among 60 plaintiffs in four lawsuits that have been filed in Nashville, Tenn., against Merck and Novartis, which makes the bone-strengthening drugs Aredia and Zometa.

The suits, which seek class-action status, claim that the drug makers failed to properly warn people of the potential side effects.

No Cure, Extremely Painful

The drugs, which belong to a category known as bisphosphonates, are being linked to a rare disease that causes the jawbone to rot called osteonecrosis of the jaw or ONJ.

"There's no cure for it, and it's extremely painful," said Knoxville, Tenn., attorney John Threadgill, who represents Wolfe and others worldwide in the lawsuits that were filed last fall. "The drugs are effective, but people who have pre-existing dental conditions are predisposed to get the condition we've sued about."

Merck was hit with a $9 million punitive damage award this week over Vioxx, which was pulled from the market in 2004 after a study linked it with increased risk of heart attack and stroke.

Fosamax is Merck's second-best-selling drug, with last year's revenue at $3.2 billion.

Threadgill said his case is "more clear cut" than the one against Vioxx because it is easier to establish a direct link between Fosamax and the disease.

"The problem we're dealing with is a really rare anomaly," Threadgill said. "This is a life changing, devastating illness that is preventable. There is no other cause for ONJ. People's jawbone just doesn't start to rot."

Merck has said it did not receive any reports of the disease in the more than 17,000 patients who participated in its clinical trials.

The plaintiffs are seeking damages as well as the implementation of a dental monitoring plan, which would require the defendants to provide dental examinations for those who are being prescribed the drugs.

Threadgill, who said he has spent most of his career defending manufacturers, was first contacted in October 2004 by a Knoxville woman taking Aredia.

Aredia and Zometa are drugs given intravenously for such cancers as breast, multiple myloma and prostate.

The original lawsuit was filed a month later, but as more plaintiffs got involved, Threadgill dismissed that case and filed four separate suits.

A similar lawsuit was filed in Florida this week.

'Potential of Widespread Catastrophic Disease'

Merck issued this statement in response to the Fosamax litigation:

"Most reported cases of bisphosphonate-associated osteonecrosis have been in cancer patients treated with intravenous bisphosphonates, but cases have occurred in patients with postmenopausal osteoporosis and other diagnoses. The cause of osteonecrosis of the jaw (ONJ) is not well understood and is likely to include a number of conditions.

"In all of our controlled clinical trials, including the 10-year data with Fosamax, which have included more than 17,000 patients, we have not had reports of osteonecrosis of the jaw occurring in patients taking Fosamax. Merck has received post-marketing reports described as osteonecrosis of the jaw occurring in patients taking Fosamax.

"Post-marketing reports do not necessarily indicate causality. On Jan. 31, 2005, Merck received a request dated Jan. 24, 2005, from the Food and Drug Administration to update the label for Fosamax to include bisphosphonate class labeling for ONJ. Merck submitted a draft-revised label to FDA on March 1, 2005. FDA comments on this draft revised label were received in June 2005, and the new label was made publicly available in July 2005."

Novartis officials could not be reached for comment.

Threadgill said he is currently working on a couple of cases against Actonel, an oral osteoporosis drug made by French drug maker Sanofi-Aventis, but no lawsuit has been filed.

"I think this probably has the greatest potential of widespread catastrophic disease of any I have ever seen, because of the sheer number of people on the drugs and the devastating nature of the problem," Threadgill said.