Erectile dysfunction as a marker for cardiovascular disease diagnosis and intervention: a cost analysis. Topicals tend to have a lower risk of side effects compared to oral medications, Dr. They are PDE5 inhibitors that allow for increased blood flow to the penis, leading to more frequent and harder erections. Side Effects Are Minimal. Take sildenafil as needed before sexual activity.AdSave Time & Money with Online Prescription for Viagra, Cialis, Sildenafil and Tadafil. Free & Private Online Consultant with Real Doctors. Reliable E.D. Meds Shipped test1.ru has been visited by 10K+ users in the past monthFree Shipping · Discreet Packaging · Real Doctors · Personalized Plan.  · Maximum dose: 20 mg orally three times a day. Injection: Initial dose: or 10 mg IV bolus three times a day. Comments: No greater efficacy was achieved with oral doses higher than the maximum recommended dose. A 10 mg injection dose is predicted to provide pharmacological effect equivalent to the 20 mg oral dose. Oral medications, like Viagra and Cialis, which require a prescription and are commonly used to treat ED, can take 30 minutes to take effect, she adds. Injections take less time .