Other contraindications include hypersensitivity to any component of the formulation, pulmonary veno-occlusion, left ventricular outflow obstruction, PAH associated with sickle cell anemia, and multiple system atrophy. ED is associated with depression, anxiety, and loss of self-esteem. No personal identifiers were included in the questionnaire and confidentiality of the information was assured in such a way that no disclosure of the collected data was made apart from the study purpose. Epistaxis was reported higher in sildenafil-treated patients with a concomitant oral vitamin K antagonist. This could be convincing because ED is usually common in older age and chronic diseases such as hypertension and type II diabetes.Sildenafil is a medicine used to treat erection problems (erectile dysfunction). Sildenafil is also sometimes used to treat pulmonary hypertension (high blood pressure in the blood vessels that supply the lungs). If you have erection problems sildenafil works by temporarily increasing blood flow to your penis when you get sexually excited.  · 10 tips to use sildenafil (aka Viagra) effectively. A set of instructions should be given to patients on sildenafil: A minimum wait of 45 minutes to 1 hour is required between taking the tablet.  · Maximum dose: 20 mg orally three times a day. Injection: Initial dose: or 10 mg IV bolus three times a day. Comments: No greater efficacy was achieved with oral doses higher than the maximum recommended dose. A 10 mg injection dose is predicted to provide pharmacological effect equivalent to the 20 mg oral dose.