The government has ordered Merck & Co. to cease promotions aimed to get doctors to prescribe its blockbuster arthritis painkiller Vioxx, saying they minimize potential safety risks.
The Food and Drug Administration told Merck to set the record straight by sending a ``Dear Doctor'' letter to all health workers who may have been exposed to the misleading campaign.
The main issue: Whether Vioxx users face an increased risk of heart attacks and strokes. A recent study comparing Vioxx to another painkiller, naproxen, suggested they do. Many heart experts are divided about the risk and want more research. But an FDA advisory panel has said Vioxx should carry a warning label about the potential risk.
Merck has argued that Vioxx falsely looked risky because naproxen thins the blood much like aspirin does and thus protected against heart attacks. It aired that view in the recent promotions that state,
``Vioxx is a wonderful, effective'' painkiller but not one that has a blood-thinning side benefit.
``In fact, the situation is not at all clear,'' the FDA responded, saying no studies prove naproxen thins blood enough to explain the discrepancy.