L-Day is upon us. That thud you just heard was billions of dollars of Lipitor sales heading over the patent cliff. Pfizer (NYSE: PFE) no longer has exclusivity on the drug as of today.

We've known about this day for years after Pfizer settled its patent litigation with Indian generic-drug maker Ranbaxy. Yet there's plenty of articles being written as if this is news.

Most seem to focus on whether Pfizer will be able to retain sales of Lipitor. The pharma giant is pulling out all the tricks in the book and inventing some of its own. Between discounts and incentives and direct-to-consumer sales, it should be able to retain some sales of the branded drug. And it'll even capture some of the generic sales through its authorized generic that Watson Pharmaceuticals will sell.

Whatever the amount of revenue Pfizer can retain from Lipitor, it'll come at substantially reduced margins, however. There are much bigger things investors should be worried about than how much low-margin sales Pfizer can retain.

The dividend
The No. 1 concern of investors should be the dividend. At 4.3%, it's a substantial portion of the returns investors are expecting. Pfizer halved its dividend in 2009 to afford the purchase of Wyeth, but it increased the dividend in 2010 and again this year. Another bump next year would give investors confidence that the cash flow will be there in the post-Lipitor era.

As a bonus, an increase in the dividend is likely to push share prices higher to keep the yield the same. Pfizer's yield looks like it's in a good place, higher than Johnson & Johnson (NYSE: JNJ), which is in a little better position since it's more diversified, but lower than peer Eli Lilly (NYSE: LLY), which faces its own steep patent cliff.

The next blockbuster
Pharma has shunned the blockbuster-or-bust mantra, realizing that drugs for smaller markets can still work. But blockbusters are still important. Not only does it take fewer blockbuster drugs to move the revenue needle, but blockbusters tend to contribute more to the bottom line; as sales ramp up, marketing expenses don't have to increase at the same rate, leading to better margins.

Pfizer and Bristol-Myers' (NYSE: BMY) Eliquis is the come-from-behind favorite to replace warfarin as the standard of care for atrial fibrillation patients. With data that looks better than Boehringer Ingelheim's Pradaxa and Xarelto from Bayer and Johnson & Johnson, it seems likely that Eliquis will be able to gain FDA approval in March and hit blockbuster status.

The other drug investors should keep their eye on is Pfizer's rheumatoid arthritis drug tofacitinib. The market is currently dominated by Abbott Labs' (NYSE: ABT) Humira, Johnson & Johnson and Merck's (NYSE: MRK) Remicade, and Pfizer and Amgen's (Nasdaq: AMGN) Enbrel, but they have to be injected or infused, while tofacitinib can be taken orally.

The breakup
Earlier this year Pfizer announced that it planned to divest itself of its animal-health and nutrition businesses, but the exact plan on how to do that -- sell, spin off, or something more creative -- is still up in the air. I've argued that generating cash should be the preferred route as long as Pfizer uses the cash to license or purchase drugs to bolster its pipeline. There's plenty of cheap biotechs out there.

Investors don't have any control over the process, but still should keep an eye on it since a spinout might result in some shares of a new company in your portfolio.

Pfizer 2.0
Big life events can be the catalyst for positive changes. Let's hope the loss of Lipitor can result in a Pfizer that's stronger -- albeit smaller -- than in its Lipitor heyday.

Looking for more dividend ideas? Check out the Fool's new free report, "Secure Your Future With 11 Rock-Solid Dividend Stocks."