In the aftermath of pharmaceutical giant Pfizer (NYSE:PFE) failing in its repeated attempts to acquire European drug maker AstraZeneca (NYSE:AZN), investors may be wondering what's next. After all, Pfizer's enormous offer and seeming willingness to pay quite a premium to no avail has left a bit of egg on management's face.

In its post-Lipitor era, organic growth has been hard to come by. And, since taking new drugs all the way to market is an extremely costly and time-consuming effort, management probably feels the easiest way to get the growth it needs now is by buying up a rival company.

Now that Pfizer has been rejected by AstraZeneca, it would be a mistake for the company to end its pursuits. The fundamental challenges facing the company, namely its severe patent losses, still remain. Since AstraZeneca is now off the table, Pfizer should bid for another U.K.-based pharmaceutical giant: GlaxoSmithKline (NYSE:GSK).

Going abroad for growth
To try to reenergize growth in its pipeline and in new overseas markets, Pfizer made several offers for AstraZeneca. AstraZeneca wouldn't budge, and now Pfizer is left by its lonesome.

Pfizer still faces tough patent expirations that continue to drag down the company's financial performance. Pfizer is enduring expiration on collaboration agreements of other key drugs, including Enbrel in the United States and Canada, as well as Spiriva in certain countries, and multi-source generic competition for Detrol LA, that are weighing on the top and bottom lines.

It's because of ongoing expirations that Pfizer's revenue fell 9%, or $1.1 billion, last quarter. This was due primarily to a 10% drop in its established pharmaceutical segment. Meanwhile, earnings per share fell 5% in the quarter.

GlaxoSmithKline can answer many of Pfizer's key questions. Glaxo is doing very well in emerging markets. Its pharmaceuticals and vaccines segment posted 2% sales growth in emerging markets and 13% sales growth in Japan last quarter.

In addition, Glaxo has a robust pipeline in some exciting new areas of therapy. For example, its HIV sales rose 4% last quarter thanks to the recent launch of integrase inhibitor Tivicay. In all, Glaxo holds 40 new molecular entities in either phase 2 or 3 clinical development.

However, it's worth noting Glaxo faces its own challenges. Sales in its pharmaceuticals and vaccines segment fell 10% in the U.S., mostly because of generic competition to its key drug Advair. Advair sales fell 30%, which matters a lot since it makes up about 30% of its respiratory sales.

At the same time, Glaxo is counting on recently launched COPD treatments Breo and Anoro take up some of the slack in its respiratory portfolio.

The vaccine portfolio will be helped greatly since Glaxo purchased the global vaccines business of Novartis earlier this year for $5.25 billion. The transaction is expected to be immediately accretive to Glaxo's EPS. In particular, Glaxo management is excited about the meningitis drug Bexsero.

Glaxo also has a strong consumer business, led by popular brands such as Aquafresh, Nicorette, and Tums. Pfizer doesn't have much of a consumer business to speak of, since it derived just 6% of its sales from consumer health care last quarter.

What Glaxo can offer Pfizer right now is clear. Pfizer expects full-year revenue to decline as much as 5% and flat earnings, while Glaxo projects modest sales growth and 6% earnings growth.

The Foolish bottom line
In summary, many of the same benefits Pfizer sought from AstraZeneca, including a favorable tax structure and a rebuilt pipeline, could be had with Glaxo as well. In addition, Pfizer would also receive the benefit of an expanded consumer health care business, which it currently doesn't have. It seems that Pfizer management intends on shifting the company toward being a nearly pure-play on pharmaceuticals, but that could be a double-edged sword.

The potential for blockbusters is compelling, but it's also a riskier pursuit than some of the diversified health care companies. Bringing Glaxo's established consumer brands and vaccine segments in might not seem sexy, but they would provide a valuable dose of consistency to Pfizer's financial performance, which has been fairly volatile over the past several quarters.