The blockbuster has been withdrawn worldwide after trial data showed an increased risk of heart disease and strokes after use beyond 18 months.
MSD acting head of PR Helen Wright has taken charge of UK crisis communications.
Media targets included the trade media for healthcare professionals and consumer press for users, said PR manager Rob Couter, adding that helplines have been set up for patients and doctors.
Around two million people are thought to use the drug globally, including 400,000 in the UK.
The drug has been continuously reviewed since its launch five years ago, with these latest results based on a study of 2,600 patients.
Since Vioxx’s launch, UK product PR has been handled by Galliard Healthcare Communications.
Agency MD Marika Freris said the agency’s role had been put ‘on hold’, with crisis PR being handled in-house.
In a statement, Raymond Gilmartin, president and CEO at parent firm Merck & Co, said: ‘Although we believe it would have been possible to continue to market Vioxx with a licence that would incorporate this new data, given the viability of alternative therapies, and the questions raised by the data, we concluded that a voluntary withdrawal was the responsible course to take.’