Pfizer (PFE -1.05%) is battling cheap knockoffs of its erectile dysfunction drug Viagra. But these aren't the typical generic drugs offered for pennies on the dollar. Viagra is still under patent in the U.S., so generic drugs aren't available yet.

Instead, Pfizer is fighting against counterfeit medications, often sold on the Internet, which may not even contain the active drug. To battle back, the pharma is entering their realm, selling Viagra direct to consumers through its website. Pfizer won't fill the orders directly; they'll go through CVS Caremark's (CVS -0.62%) mail-order pharmacy, which will presumably get a cut of the sales.

Patients will still need a prescription, so it isn't particularly more convenient than going to the pharmacy. For bashful patients, though, at least the mailman won't know what's in the package, unlike the pharmacist at the counter.

Through Pfizer's website, standard shipping is free. But if you've got a hot date this weekend, you'll have to pay extra for expedited shipping.

Pfizer doesn't seem to be offering any special discounts through its website. Customers can get three free pills on the first order and 30% off their second prescription, but that's also available through traditional local pharmacies.

While Pfizer is billing the move as a way to compete against counterfeit drugs, it also seems like a good move to capture patients who might use other branded drugs for erectile dysfunction: Eli Lilly's (LLY 0.54%) Cialis and Bayer and GlaxoSmithKline's (GSK -0.88%) Levitra. In the first quarter, Viagra sales were down 7% year over year, while Cialis sales  were up 11% year-over-year, partially due to increased prices in the U.S. Like Viagra, Levitra sales could use a boost; sales were down 9% year over year in the first quarter.

I like Pfizer's out-of-the-box thinking. It made a similar departure from the norm when generic Lipitor from Ranbaxy and Teva Pharmaceuticals hit the market. Rather than ignoring the competition, Pfizer came out fighting, offering steep discounts on its branded drug to make the price comparable to the generics.

Maybe there's an in-roads for VIVUS (VVUS) using this strategy. The biotech has a Food and Drug Administration-approved erectile dysfunction drug called Stendra that it hasn't launched yet, claiming that the company's looking for a partner. It seems safe to assume that it's been hard to get pharma excited about competing against Viagra and Cialis given that the drug was approved more than a year ago. VIVUS has experience selling through mail-order pharmacies -- until recently, it was the only way that patients could get its obesity drug, Qsymia; maybe it should follow Pfizer's lead and launch on the Internet first.