Viagra pill John Greim | LightRocket | Getty Images

Pharmaceutical giant Pfizer holds a lead in the erectile dysfunction market even as competition from generics erodes sales of its once-blockbuster male libido treatment, Viagra. The medication, originally developed with the intention to treat high blood pressure in adults, became a hit for males struggling in the bedroom and the New York-based drugmaker when it was introduced to the U.S. market in 1998. In its first quarter, Viagra brought a total of $400 million in revenue for Pfizer and would later produce annual sales of about $1.8 billion. An estimated 1 in 10 men are affected by erectile dysfunction, or ED, according to the Cleveland Clinic. Viagra was the first noninvasive treatment for male impotency and opened up a previously undiscussed dialogue between men and their doctors about sexual health. Nearly 21 years later, sales of the brand-name drug have dropped. Pfizer lost exclusive rights to the drug in December 2017, bringing with it a flood of generic versions. U.S. sales of "the little blue pill" declined 73 percent year over year in 2018 from $789 million to $217 million, Pfizer said in its fourth-quarter earnings report, as generics entered the market.

A strategy

Despite generic competition from other drugmakers, Pfizer has been able to maintain a significant market share thanks, in part, to launching its own generic version of the blue, diamond-shaped pill. In late 2017, Pfizer announced it would produce a generic version, called sildenafil, at half the cost of the brand name. The company also said at the time it would offer new discount programs and increase its copayment card discounts to make the brand version more accessible to patients. According to GoodRx, 65 percent of ED prescriptions filled from Dec. 1, 2018, to Jan. 31, 2019, were for Viagra or its generic version. Thirty percent of prescriptions were for rival Cialis and its generic, tadalafil. Levitra and generic vardenafil came in third at 5 percent of the market. Additionally, the gap between prescriptions filled for brand-name versus generics is large. Ninety percent of the prescriptions filled over that same two-month time period were for Pfizer's generic version, while only 10 percent prescribed were for the brand name, according to GoodRx. "The data can't explain the reason behind why people take the generic over the brand, or vice versa," said Tori Marsh, data and content manager at GoodRx. "But since generic Viagra is more affordable than the brand it's likely that cost is a factor here." Marsh added most health insurers require that members be prescribed a generic when there is one available, and that pharmacies dispense the generic.

Taking it online