Before they even step into a courtroom, lawyers for Glaxo are taking an aggressive posture against plaintiffs’ lawyers looking to drum up business over Avandia, the drug giant’s embattled diabetes drug. According to Bloomberg, Glaxo’s lawyers at Pepper Hamilton have sent letters to a handful of plaintiffs’ lawyers running TV ads soliciting clients for Avandia cases it says are false or misleading. (HT: Pharmalot Blog)

A study published in the New England Journal of Medicine in May found Avandia users were 43% more likely to have a heart attack than those taking other diabetes medicines. Prescriptions for Avandia — the world’s leading diabetes drug — have sinced plummeted since the study’s release. Glaxo says other studies found no increased risk of heart problems.

“Lawyers have a right to advertise, but they have to play by the rules just like we do,” said a Glaxo executive to Bloomberg. “We’ve only written the letters to people whose advertisements cross the line, in our opinion,” said the Glaxo spokeswoman. The letters, reviewed by Bloomberg, contend that some of the plaintiffs’ firms’ ads “are actionable” because they imbue the study with “a definitive, conclusory quality,” according to the Bloomberg story.

A New York lawyer named David Ratner told Bloomberg that he decided to pull TV ads after receiving the letter, but he continues to advertise for cases on the Internet. “We got about 12,000 calls and about 1,200 potential cases out of them,” Ratner said. 12,000 calls? By the Law Blog’s fuzzy math, that’s about 250 calls per day since the study was published and the FDA issued an alert in late May.

Anyhow, Avandia ads are rampant on the web. While the Law Blog hasn’t seen any of the TV spots, we just googled “Avandia” and turned up a ton of links to plaintiffs firms seeking Avandia cases. Says Ashcraft & Gerel’s Web site: “If you or a loved one has experienced a heart attack or has died of heart related (cardiovascular) disease after using the diabetes medication Avandia, you may have a lawsuit that should be pursued.”