Many big pharmaceutical companies managed to weather the recent flurry of patent expirations that affected their top lines. Merck (MRK 0.34%), a Dow component and one of the planet's largest drugmakers, was hit hard by the loss of exclusivity for its multibillion-dollar drug Singulair, and it now relies on blockbuster drugs Januvia and Janumet. But will the big pharma have to deal with more patent expirations in the coming years? In the following video, analysts David Williamson and Max Macaluso focus on the drugs that Merck stands to lose protection on in the coming years.