Drug therapy in impotence has evolved so as to minimise the side effects. Prostaglandin E1 is now commonly used, one of its benefits being a lower risk of experiencing priapism (persistent and painful erections). The dose required is patient-dependant and determined by measuring the response of the patient to several dosages and then adjusting the amount required for the desired effect.
The patient should be shown the correct injection technique, at the lateral base of the penis, and taking care to avoid the urethra ventrally and the neurovascular bundle dorsally. All patients should be made aware of the risks involved, such as priapism and fibrosis at the site of injection. Patients should report to their clinician if an erection is experienced for more than 4 hours.
Many patients find this method for treating impotence uncomfortable or inconvenient, and as a result there is a high drop out rate of up to 50%.