One of these is PAH. Some platforms have a digital pharmacy that ships the medication to your home, while others send an electronic prescription to your local pharmacy. This increase in blood flow results in a firmer, longer-lasting erection. While each PDE5 inhibitor differs slightly, they’re very similar in treating erectile dysfunction. Tadalafil was approved in in the United States for the treatment of pulmonary arterial hypertension [28] and is under regulatory review in other regions for this condition. All PDE5 inhibitors, including Viagra and Cialis, require a valid prescription regardless of the pharmacy or provider.Depending on your symptoms and needs, you may be prescribed Viagra, sildenafil, Cialis, tadalafil, Stendra, paroxetine, or a combination of tadalafil and sildenafil, available as mints or pills. Prices range from $3 to $ per dose or $82 to $ for a monthly supply, depending on the medication. How Cialis Works. Tadalafil and other PDE5 inhibitors primarily work by inducing muscle relaxation. Tadalafil stops the breakdown of a chemical responsible for relaxing muscles. In ED and PAH, the drug targets muscle cells in blood vessels. When the blood vessel muscle cells relax, this expands the vessel and increases blood flow; this . Comparison of online Cialis prices. Brand-name Cialis: Generic Cialis (tadalafil) Daily generic Cialis (tadalafil) Hims: $ per month (5mg) starting at $40 per month (5mg, 10mg, 20mg).