Since , Viagra (sildenafil) has been used for treating erectile dysfunction (ED). It’s available by prescription for males ages 18 years and older. Side effects are not frequent and usually.These medicines are called PDE5 inhibitors. Often, these are prescribed for chest pain called angina. These include a heart attack, stroke or a serious heart rhythm disorder in the past six months. Children 1 year of age and older weighing 45 kilograms kg or more—20 mg 3 times a day. Please expect up to 4 to 6 weeks for reimbursement.CHOOSE BRAND-NAME VIAGRA. The original little blue pill prescribed by doctors for over 20 years. Clinically proven to treat men with erectile dysfunction (ED) Ongoing commitment to product quality and safety monitoring. Since , Viagra (sildenafil) has been used for treating erectile dysfunction (ED). It’s available by prescription for males ages 18 years and older. Side effects are not frequent and usually. Viagra (sildenafil) is a brand-name prescription drug that’s used to treat erectile dysfunction (ED). Learn about side effects, warnings, dosage, and more.Its effects often last for 4 to 5 hours. Medicines that you take by mouth are called oral medicines. Storage Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. To use the oral liquid: Shake the bottle well for at least 10 seconds before each use. Different brands may not work the same way. It lasts 4 to 5 hours, or longer if you have mild to moderate ED. The most common side effects of VIAGRA: headache; flushing; upset stomach; abnormal vision, such as changes in color vision such as having a blue color tinge and blurred vision; stuffy or runny nose; back pain; muscle pain; nausea; dizziness; rash.