Pfizer (NYSE:PFE) is one of the globe's biggest drugmakers, and its stock is a staple in dividend portfolios.

However, patent expiration of key drugs has shaved billions off its top line, putting pressure on Pfizer to use its substantial cash position to bolster its research pipeline. As a result, dividend investors are right to question whether sliding sales threaten its dividend payout.

In the following slideshow, you'll learn more about Pfizer's patent headwind and how Pfizer compares to industry peers like AstraZeneca (NYSE:AZN) and Merck (NYSE:MRK) when it comes to dividend payouts.