Cialis, the maker of the erectile dysfunction drug, could be the first prescription drug of its kind to be sold over counter as a result of a licensing agreement between Eli Lilly and Co. and Sanofi, a French drug maker.

The Associated Press reported that the two companies are hoping to begin selling Cialis OTC over the counter without any doctor's prescription by 2018, which also marks the year the drug's patents expire in the U.S. and in Europe.

Once the patent expires, other companies can produce and manufacture cheaper generic versions that would essentially cut into Eli Lilly's profits. Last year Cialis made $2.16 billion in sales, which made it Lilly's fourth best-selling drug.

If regulators approve Lilly's bid to sell Cialis over the counter, the Indianapolis drug maker could sell the product as an impotence treatment drug while still turning a profit, according to the AP.

Sanofi is in charge of commercializing the nonprescription version of Cialis in whatever country it is approved in. Lilly, on the other side of the deal, will continue to manufacture the tablet drug, which is made in Puerto Rico.

More than 45 million men have been prescribed the erectile-dysfunction-solving drug since it first became approved in Europe back in 2002. It began selling in the U.S. in 2003.

Dave Ricks, a senior vice president of Lilly, said Cialis has continued to be a safe and effective drug that should be approved for over-the-counter use. He added that selling the drug over the counter would produce a safer alternative than purchasing a fake for of it online.

A number of men don't like talking to their doctor about their problem with impotence and therefore don't get treatment. Over-the-counter availability would help those men, Ricks said.

"Half of (American) men over 40 suffer ED," Ricks said. "But the current market (for prescription ED drugs) only represents a fraction (of potential patients). Men don't want to go through the hassle and sometimes discussions with doctors. There is a need to self-diagnose. We think that (over-the-counter) availability is key to helping guys."