The substance is the same under both trade names. How should this medicine be used? Continue to take sildenafil even if you feel well. Often, these are prescribed for chest pain called angina. These small differences affect the way each medication works, such as how quickly it takes effect and wears off, and the possible side effects.According to price-comparison site test1.ru, generic Revatio will cost you as little as $ per pill, depending on where you fill your prescription. That’s . 1. How it works. Sildenafil may be used to treat erectile dysfunction (ED or impotence) in men (Viagra brand) or pulmonary arterial hypertension in both men and . The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called .