We also looked at additional services, such as access to digital pharmacies and home delivery options. Your doctor may adjust your dose as needed and tolerated. Do not press on the plunger of the syringe. Generic vs. Use only the brand of this medicine that your doctor prescribed. · For oral dosage forms (suspension or tablets): Adults—20 milligrams (mg) 3 times a day. Your doctor may adjust your dose as needed and tolerated. However, the . Updated on April 21, Key takeaways: Viagra (sildenafil) is a prescription medication used to treat erectile dysfunction. Headache, flushing, and upset stomach are common . Key Specs Cost: Consultation prices vary based on the prescriber; $5 generic prescriptions Medical Consultation Required: Yes Medications Prescribed: .