Health insurers, unions and other private groups that paid for prescriptions for withdrawn painkiller Vioxx have reached an $80 million settlement with its maker, ending another part of the multipronged litigation.

Such third-party payers had filed about 190 claims against Whitehouse Station, N.J.-based drugmaker Merck & Co. They said they would not have covered Vioxx had they known about its cardiovascular risks, which they argued Merck concealed.