Apomorphine is a non-selective D1/D2 receptor agonist with moderate efficacy and good tolerability in the treatment of mild ED (80). Apomorphine can be administered via subcutaneous injection or sublingually. However, studies have shows a lower efficacy for apomorphine compared to oral sildenafil (81,82). Apomorphine has a set role in the management of PD for non-motor symptoms, and has been reported to cause spontaneous erections and possible hypersexuality in PD men (83,84). Its role in the management of ED has been postulated for men with PD but should be considered as an alternative to sildenafil.
In some cases, however, these drugs may be unsuitable for patients with heart disease. If you are considering one of these drugs and you have heart disease, as many diabetics do, be sure to tell your doctor. In rare cases, the pills may create “priapism,” a prolonged and painful erection lasting six hours or more (although reversible with prompt medical attention).
Radical prostatectomy for the treatment of prostate cancer poses a significant risk of ED. A number of factors are associated with the chance of preserving erectile function. If both nerves that course on the lateral edges of the prostate can be saved, the chance of maintaining erectile function is reasonable. The odds depend on the age of the patient. Men younger than 60 years have a 75-80% chance of preserving potency, but men older than 70 years have only a 10-15% chance.
The Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) study, designed to determine whether an individual man’s sexual outcomes after most common treatments for early-stage prostate cancer could be accurately predicted on the basis of baseline characteristics and treatment plans, found that 2 years after treatment, 177 (35%) of 511 men who underwent prostatectomy reported the ability to attain functional erections suitable for intercourse. 
Alprostadil is injected into the side of penis with a very fine needle. It's of great value to have the first shot in the doctor's office before doing this on your own. Self-injection lessons should be given in your doctor's office by an experienced professional. The success rate for getting an erection firm enough to have sex is as high as 85% with this treatment. Many men who do not respond to oral PDE5 inhibitors can be ‘rescued' with ICI.