It's new. It's exciting. It had better pay off.

That basically sums up Merck's (NYSE: MRK) post-acquisition pipeline, which the company outlined for investors yesterday. The acquisition of Schering-Plough has undoubtedly helped the pipeline. Schering-Plough makes up about 35% of the current value of the combined company, but 45% of the combined pipeline came from Schering-Plough. If you look at drugs that will have an effect the soonest, phase 3 drugs and those awaiting decisions on marketing applications, nearly half of the drugs -- 11 out of 23 -- came from Schering-Plough.

Ironically, Schering-Plough stocked its pipeline through its smaller acquisition of Dutch Akzo Nobel's Organon BioSciences subsidiary. Companies can often get bigger potential rewards for the money by purchasing smaller companies with fewer drugs on the market -- think Eli Lilly's (NYSE: LLY) acquisition of ImClone Systems -- or even development-stage drugmakers, as Bristol-Myers Squibb (NYSE: BMY) and Johnson & Johnson (NYSE: JNJ) did last year. Of course, those potential rewards come with increased risk, and don't offer an immediate fix for ailing revenue lines like larger acquisitions do.

It's a little late at this point to convince Merck to use one or both of those strategies, so let's get back to the pipeline. In general, Merck's and Schering-Plough's pipelines fit pretty well -- apparently better than Pfizer's (NYSE: PFE) pipeline melded with Wyeth's. There were only two places where Merck had to choose between rival compounds -- one for hepatitis C and one for cancer.

That's good news because Merck can use all the growth it can get its hands on. Blood pressure medications Cozaar/Hyzaar, a $3.6 billion franchise, are losing patent protection this year, and other blockbuster products like HPV vaccine Gardasil and cholesterol drugs Vytorin and Zetia have stalled out.

Merck's potential looks a lot better than it did a year ago, but only time will tell if the results pan out enough to justify the $41 billion price tag.

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.