In a report published in the Archives of Internal Medicine, scientists from the U.S. Food and Drug Administration (FDA) revealed that the popular painkiller Vioxx has been linked to five cases of meningitis.

Vioxx (chemical name: rofecoxib) was approved in May 1999 for the treatment of osteoarthritis, management of acute pain, and treatment of primary dysmenorrhea.

In the U.S. alone, from May 1999 through Feb. 2001, seven cases of aseptic meningitis were reported in patients receiving the drug, the researchers noted. Two cases were not included for further analysis because there was not enough information to assess causality, they explained.

The patients (four females ranging in age from 16 to 67, and one 40-year-old male) had been prescribed the drug for osteoarthritis and rheumatoid arthritis, neck pain, carpal tunnel syndrome, and postoperative inflammation. None had a history of aseptic meningitis but began displaying symptoms within a few days of taking the drug. The symptoms included headache, fever, photophobia, altered mental status and elevated levels of protein, among others.

Although none of the patients died, all required hospitalization. They all improved after discontinuing the Vioxx therapy, the report stated.

This isn't the first time that pain killers have been linked to aseptic meningitis. Previous reports have linked the condition to other nonsteroidal anti-inflammatory drugs such as ibuprofen and naproxen.

As a result of the study, the FDA has ordered Merck to add meningitis to the growing list of potential side effects for Vioxx. Last year, the medical journal The Lancet reported a possible link between Vioxx and kidney damage. In addition, the critics claim the drug is associated with a fourfold increase in the risk of heart attack for women.