Between its purchase of Schering-Plough and shifting sales from its joint ventures to the revenue line, Merck's (NYSE: MRK) revenue more than doubled in the first quarter. Of course, the true number investors should care about is the 7% increase in sales compared with sales as if the two companies were one last year.

And kudos to the company for offering up Schering-Plough's historical drug sales numbers for investors. Pfizer (NYSE: PFE) left the previous quarter's sales blank in the table in its press release, leaving investors to go look up sales of Wyeth's legacy products on their own.

A 7% growth rate isn't exactly high growth, but it isn't too shabby either. Merck's diabetes drug combo, Januvia and Janumet, continue to grow -- up 24% and 56%, respectively -- unfazed by the launch of me-too drug Onglyza from Bristol-Myers Squibb (NYSE: BMY) and AstraZeneca (NYSE: AZN). Remicade, which Merck now sells abroad for Johnson & Johnson (NYSE: JNJ), was also a strong performer, growing 30% year over year.

But the best news for investors wasn't the strong performers; it was cholesterol drugs Vytorin and Zetia not falling. In fact, Zetia increased 5% while Vytorin was flat year over year. Combined, the drugs had been Merck's top seller, but unflattering clinical-trial data had pushed them to the second spot behind allergy drug Singulair. At this point, investors should be content if Vytorin and Zetia can maintain sales and hope that an outcome study that's in progress says that the drugs help reduce heart attacks and other heart complications.

Merck isn't completely out of the woods. The company has to prove to investors that it can make a large integration work -- something it has never done and others have flubbed up. The company also began to face generic competition for multibillion-dollar blood pressure drugs Cozaar and Hyzaar last month, which will provide plenty of headwind -- even if my fellow Fool Rick Munarriz would rather me not use that word.

Still, with a pipeline full of drugs -- which we'll get a better view of next week at its investors day -- Merck seems to be in a good position to grow revenue and earnings in the years ahead.