A thorough medical history and physical examination should be undertaken to diagnose ED, identify potential underlying causes and appropriate treatment. There is a degree of cardiac risk associated with sexual activity. Therefore, physicians should consider the cardiovascular status (CV status) of the patient prior to initiating any treatment for ED. In clinical trials in the US, Sildenafil has been shown to have systemic vasodilatory properties that result in transient decreases in blood pressure. Prior to prescribing Sildenafil, physicians should carefully assess whether their patients with underlying conditions could be adversely affected by such vasodilatory effects especially in combination with sexual activity. Patients with increased susceptibility to vasodilators include those with left ventricular outflow obstruction (e.g. aortic stenosis, hypertrophic obstructive cardiomyopathy or those with the rare syndrome of multiple system atrophy manifesting as severely impaired autonomic control of blood pressure.
Agents for the treatment of ED should be used with caution in patients with anatomical deformations of the penis such as angulation, cavernosal fibrosis or Peyronie's disease or in patients who have conditions which may predispose them to priapism namely sickle cell anemia, multiple myeloma or leukemia. Agents for the treatment of ED should not be used in men for whom sexual activity is inadvisable. The safety and efficacy of combinations of Sildenafil with other treatments for ED have not been studied. Therefore, the use of such combinations is not recommended.
Caution is advised when Sildenafil is administered to patients taking an α-blocker, as the co-administration may lead to symptomatic hypotension in a few susceptible individuals. In order to minimize the potential of developing postural hypotension, patients should be hemodynamically stable on α-blocker therapy prior to initiating Sildenafil treatment. Initial intake of Sildenafil at lower doses should be considered. In addition, physicians should advise patients what to do in the event of postural hypotensive symptoms.
In vitro studies with human platelets indicate that Sildenafil potentiates the anti-aggregatory effect of sodium nitroprusside. There is no safety information on the administration of Sildenafil to patients with bleeding disorders or active peptic ulceration. Therefore, it should be administered with extreme caution to these patients.
A minority of patients with the inherited condition retinitis pigmentosa have genetic disorders of retinal phosphodiesterases. There is no safety information on the administration of Sildenafil to patients with retinitis pigmentosa, therefore Sildenafil should be administered with caution to these patients.
There are no recommendations with regards to detrimental effects on the ability to drive or operate machinery.