Comparison with actions of other PDE5 inhibitors[ edit ] Sildenafil and vardenafil inhibit PDE6, an enzyme found in the eye, more than tadalafil. Take tadalafil at around the same time every day. You’ll soon start receiving the latest Mayo Clinic health information you requested in your inbox. Talk to your doctor about which dosing schedule is right for you. In BPH, the medication relaxes the urinary tract and bladder muscles, allowing for more effortless urine flow. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.Generic name: tadalafil [ ta-DAL-a-fil ] Brand names: Adcirca, Cialis Drug classes: Agents for pulmonary hypertension, Impotence agents. Medically reviewed by Kaci Durbin, MD. Last updated on Uses; Warnings; Before taking; Dosage; Side effects; Interactions; FAQ; What is tadalafil?  · Adcirca Cialis Descriptions Tadalafil is used to treat men who have erectile dysfunction (also called sexual impotence). Tadalafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. Tadalafil (Cialis) is available in generic and brand versions in several doses as an oral tablet. You can take Cialis as needed or once a day, depending on the dose and how it’s prescribed.