Key facts It usually takes 30 to 60 minutes for sildenafil to work for erectile dysfunction. Ask your doctor if you have any questions. Trimazosin Other Interactions Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Deaths were first reported after approximately one year of use, and hence sildenafil, particularly chronic use, is not recommended in pediatric patients with PAH. Talk to your doctor if you take too much sildenafil and you’re worried about any of these side effects: headaches. Contraindications Nitrates increase cGMP formation, while sildenafil inhibits cGMP degradation causing the combination to produce severe life-threatening hypotension synergistically; coadministration of sildenafil with nitrates is contraindicated. · US Brand Name. Revatio; Viagra; Descriptions. Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. The penis is one . Sildenafil (Viagra brand) only works following sexual stimulation. It works within 30 to 60 minutes, but may be taken up to four hours before sexual activity. Sildenafil (Revatio brand) reduces high blood pressure associated with pulmonary arterial hypertension (PAH). This improves the ability to exercise in people with PAH and delays . Sildenafil is a medication used in the management and treatment of erectile dysfunction and pulmonary arterial hypertension. It is in the phosphodiesterase-5 inhibitor (PDE5-I) class of medications. This activity describes the indications, actions, adverse effects, and contraindications of sildenafil as an agent in the clinical setting. Knowledge .