Makers of viagra?

Pfizer is the original manufacturer of Viagra [1].

Who Makes the Generic Versions of Viagra?

Following the patent expiry of Viagra, several pharmaceutical companies have begun manufacturing generic versions of sildenafil, the active ingredient in Viagra. These companies include Teva Pharmaceuticals, Aurobindo Pharma, and Dr. Reddy's Laboratories, among others [2].

When Did Viagra's Patent Expire?

Viagra's primary patents began to expire around 2011 in the United States, leading to the availability of generic sildenafil [3].

What is the Active Ingredient in Viagra?

The active ingredient in Viagra is sildenafil citrate [1]. This medication is used to treat erectile dysfunction [1].