Vigora 100 mg is a medication used to treat erectile dysfunction (ED) in men. It contains Sildenafil Citrate as its active ingredient, which is the same component found in Viagra. Sildenafil belongs to a class of drugs known as PDE5 inhibitors, which help to increase blood flow to the penis, allowing a man to achieve and maintain an erection during sexual activity. Sildenafil: Inhibits the enzyme phosphodiesterase type 5 (PDE5). This inhibition increases levels of cyclic guanosine monophosphate (cGMP), leading to relaxation of smooth muscle in the blood vessels of the penis, allowing for increased blood flow during sexual stimulation.