Penegra 50 mg is a medication that typically contains sildenafil citrate as its active ingredient. Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor commonly used to treat erectile dysfunction (ED) in men. Penegra, like other medications with sildenafil citrate, works by increasing blood flow to the penis during sexual stimulation, facilitating the ability to achieve and maintain an erection.