Pfizer and Merck have done a good job beating Wall Street's per-share expectations in the face of real headwinds. Pfizer has gone through a dramatic reorganization to fight this challenge, while Merck is standing pat with its more diverse business model.

In this video, health-care analyst David Williamson discusses both companies second-quarter results in greater detail, how their different approaches are working out, and what key drugs in their respective pipelines investors should focus on.

David Williamson owns shares of Pfizer, Zoetis, and Merck. Follow David on Twitter: @MotleyDavid.

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