Erectile dysfunction drug Cialis seeking over-the-counter approval

Two boxes with the anti-impotence drug Cialis (tadafil) are pictured in a Munich pharmacy February 4, 2003.

If two large drug makers get their way, consumers may be able to buy the impotence drug Cialis directly off a pharmacy shelf in a few years' time, without a doctor's prescription.

Cialis maker Eli Lilly & Co. has struck a licensing deal allowing French drug maker Sanofi SA to sell a nonprescription version of the pill in major markets if regulators approve—still a big "if." The prescription erectile-dysfunction drug racked up $2.2 billion in global sales last year, surpassing rival Viagra, which had sales of $1.9 billion.

The companies say over-the-counter Cialis could provide easier treatment access for impotence sufferers, and could also help stem the illicit online sale of fake or stolen Cialis. The few over-the-counter options currently found in pharmacies include non-Food and Drug Administration-approved dietary supplements that claim to enhance male potency, such as ExtenZe and Libido-Max.

Sanofi is acquiring the exclusive rights to seek regulatory approval for over-the-counter Cialis in the U.S., Europe, Canada and Australia, and to begin selling it after the expiration of certain patents for tadalafil, Cialis's generic name. Patents are due to expire no sooner than 2017 in the U.S. and Europe.

But the OTC project could face hurdles, including safety concerns. Sanofi will have to demonstrate to government drug regulators that men can correctly decide whether to take the drug—and use it safely—without a doctor's guidance. Cialis, like Viagra, can cause a sudden drop in blood pressure if it is taken with certain heart and blood-pressure medications, causing fainting or even death, among other adverse events linked to the drugs.