However, the dose is usually not more than 80 mg 3 times a day. The combination can cause a dangerous fall in your blood pressure. If you are taking sildenafil to treat erectile dysfunction, follow your doctor’s directions and the guidelines in this paragraph. Children 1 year of age and older weighing 20 kg or less—10 mg 3 times a day. To use the oral liquid: Shake the bottle well for at least 10 seconds before each use. If you already use medicine for high blood pressure hypertension , sildenafil could make your blood pressure go too low. Check with your doctor immediately if any of the following side effects occur: Less common burning feeling in the chest or stomach burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feelings cloudy or bloody urine.Viagra (sildenafil) is a prescription drug that’s used to treat erectile dysfunction (ED). The drug comes as a tablet you’ll take by swallowing. It’s usually taken as needed about 1 hour. Rarely reported side effects include: an erection that will not go away (priapism). If you have an erection that lasts more than 4 hours, get medical help right away. If it is not treated right away, priapism can permanently damage your penis. sudden vision loss in one or both eyes. meijer specialty pharmacy. You can get your specialty medications at any of our Meijer pharmacies. We’ll even deliver them to your home. Because you’ve got enough things to .