Side effects Side effects of oral ED medicines are often mild. The information provided is for educational purposes only and is not intended to replace discussions with a healthcare provider. This medication is taken with or without food an hour before sex. It might work longer if you have mild to moderate erectile dysfunction. Kidney disease that needs to be treated with dialysis. Pearlman says the availability of an easy-to-access treatment for men dealing with ED is welcome news. These medicines all work well for ED.Viagra can help you have an erection when sexual stimulation occurs. An erection will not occur just by taking a pill. Follow your doctor’s instructions. provides . Currently, there are no over the counter alternatives to Viagra available. Viagra (sildenafil) is a prescription medication, meaning it’s not available over the counter from your local. generic Revatio and Viagra Used for Pulmonary Hypertension and Erectile Dysfunction MORE expand_more Check your prescription Prescription 20mg sildenafil (30 tablets) .