Subsequently, the FDA approved both vardenafil [27] and tadalafil in Tadalafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow more easily. 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. What should I do if I forget a dose? When purchasing via boots.Cialis isn’t available over the counter. Your doctor has to prescribe Cialis for ED or other conditions the medication treats. You may also be able to obtain this medication with the help. Tadalafil, or generic Cialis, is most commonly used to treat erectile dysfunction (ED). However, it’s also used to treat benign prostatic hyperplasia (BPH) and pulmonary arterial hypertension. Cialis (tadalafil) is a popular medication used to treat erectile dysfunction. It’s available in tablets ranging from mg to 20mg. It can cost more than $ for a month’s supply, depending on the dosage you need and the pharmacy you visit. You can save more than 90% on the average retail price at certain pharmacies by using a GoodRx .