Precautions It is important that you tell all of your doctors that you take sildenafil. Sildenafil is also sometimes used to treat pulmonary hypertension high blood pressure in the blood vessels that supply the lungs. Do not use more of it and do not use it more often than your doctor ordered. Dosing The dose of this medicine will be different for different patients. Some people may also have ringing in their ears tinnitus or dizziness. · 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. Viagra, the much-hyped drug that’s supposed to remedy “erectile dysfunction” in men, has made its way to the Philippines, thanks to a recent stamp of approval by the Philippine Department of. Sildenafil (Viagra) is a medicine used to treat erectile dysfunction (ED, also called impotence). Sildenafil works by helping to relax the blood vessels in the penis, allowing more blood to flow in and cause an erection. You should take sildenafil about an hour before planned sexual activity, so it has time to work.