The active ingredient in Fildena 100 mg Sublingual Tablets is Sildenafil Citrate, which is a PDE5 inhi***or. It works by relaxing the blood vessels in the penis, improving blood flow when you're sexually aroused, thus helping to achieve and maintain an erection. Unlike regular tablets that are swallowed, Fildena 100 mg Sublingual Tablets are placed under the tongue, where they dissolve and are absorbed directly into the bloodstream through the mucous membranes in the mouth. Some men may prefer sublingual tablets over traditional oral tablets because they are easier to take, especially for those who have difficulty swallowing pills.