If you will be taking this medicine for pulmonary arterial hypertension, your doctor will want to check your progress at regular visits. Sildenafil Viagra is used to treat erectile dysfunction impotence; inability to get or keep an erection in men. Do not take more or less of it or take it more often than prescribed by your doctor. The penis is one of the areas where this enzyme works. Children 1 year of age and older weighing 20 kg or less—10 mg 3 times a day. If you see air bubbles in the syringe, repeat the steps. Make sure you tell your doctor if you have any other medical problems, especially: Abnormal penis, including a curved penis or birth defects of the penis—Chance of problems occurring may be increased and this medicine should be used with caution in these patients. · a light-headed feeling, like you might pass out. Common sildenafil side effects may include: flushing (warmth, redness, or tingly feeling); headache, dizziness; heartburn, nausea, or upset stomach. abnormal vision (blurred vision, changes in color vision) runny or stuffy nose, nosebleeds; sleep problems (insomnia); or.  · 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 of the areas where . AdSave Time & Money with Online Prescription for Viagra, Cialis, Sildenafil and Tadafil. Free & Private Online Consultant with Real Doctors. Reliable E.D. Meds Shipped : Hair Loss · Premature Ejaculation · Sexual Health · Privacy Policy.