Tadalafil does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus HIV. However, because sexual stimulation is required to initiate the local penile release of nitric oxide, tadalafil’s inhibition of PDE5 will have no effect without sexual stimulation. Tadalafil Adcirca is used to improve the ability to exercise in people with pulmonary arterial hypertension PAH; high blood pressure in the vessels carrying blood to the lungs, causing shortness of breath, dizziness, and tiredness. The medication will be effective for up to 36 hours. You should only be treated with one of these products at a time.20 mg The cost for these different strengths depends on whether you have insurance, your individual plan coverage, and your treatment plan. For example, Cialis . Search Cialis (type in keywords) Product Information Select a product Search Medical Information. If you wish to report an adverse event or product complaint, please call 1 . Take tadalafil (Cialis) as prescribed by your provider. If you’re taking tadalafil (Cialis) as-needed for ED, you should take no more than one dose per day. The effects of tadalafil (Cialis) should last for up to 36 hours after a dose. Taking this medication more often can raise your risk for serious side effects, such as priapism or vision.