Tazzle is a medication used to treat erectile dysfunction (ED). It typically contains tadalafil as its active ingredient. Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor, similar to sildenafil (Viagra) and vardenafil (Levitra). Tadalafil works by increasing blood flow to the penis during sexual stimulation. It helps relax the blood vessels in the penis, allowing for improved blood circulation and facilitating an erection.