Teva Pharmaceuticals (NYSE:TEVA) saw revenue fall 8% in the fourth quarter from a generic double whammy.

Its narcolepsy drug Provigil saw generic competition from Par Pharmaceutical and Mylan, causing sales of the branded drug to drop to $25 million in the fourth quarter from $350 million in the year-ago quarter .

And year-over-year comparison of sales from Teva's generic drugs were hurt by last year's stellar quarter when it benefited from U.S. launches of generic versions of Eli Lilly's (NYSE:LLY) Zyprexa and Pfizer's (NYSE:PFE) Lipitor. Generic sales in the U.S. were down 17% year over year.

Note that decreasing sales of generic versions of Zyprexa and Lipitor doesn't actually help Lilly and Pfizer. Teva's lower sales are due to increases in the number of companies selling the generics, which hurts Lilly and Pfizer as well.

Speaking of competition, investors should be worried about Teva's multiple sclerosis drug Copaxone. The drug, which made up 20% of Teva's revenue and a larger percentage of the company's earnings, will likely see competition from Biogen Idec's (NASDAQ:BIIB) oral multiple sclerosis drug Tecfidera. The Food and Drug Administration is expected to approve the drug shortly.

Teva plans to submit an application with the FDA to establish a recommended dose of three times per week for Copaxone. While three injections is less than seven, it's still more than zero, the number of injections required for oral Tecfidera.

It seems inevitable that Biogen will cut into Copaxone sales, although don't expect a mad exodus from Copaxone when Tecfidera is launched. Like many new drugs that just offer incremental increases, doctors will likely try it on a few patients before making it a staple in their medicine bag.

It's hard to get excited about a ho-hum quarter and the potential for declining sales of its most important branded drug. About the only thing keeping investors interest right now is that the company increased its dividend by 15%. At 3.2% yield, investors are at least getting paid a little to be patient and wait out any downturn.

Fool contributor Brian Orelli has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not 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.