Midsummer is considered prime beach season, but investors know that, more importantly, it's second-quarter earnings season.

With that in mind, this episode of The Motley Fool's Market Checkup is dedicated to heavy hitters in the pharmaceutical industry. Watch and find out how the second-quarter results of four Big Pharma stocks stack up, and what challenges and opportunities lie ahead for them.

In this video, health-care analysts David Williamson and Max Macaluso drill down on Merck's recent results, detailing everything investors need to know, including whether the company is becoming too reliant on its blockbuster diabetes drug Januvia.

David Williamson owns shares of Pfizer and Merck. Follow David on Twitter: @MotleyDavidMax Macaluso, Ph.D., and The Motley Fool have no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.