Intracavernous injection therapy is the most effective form of pharmacotherapy for ED
- does not require an intact nerve supply and can therefore be highly effective after spinal cord injuries and after major pelvic surgery such as after radical prostatectomy
 - due to the invasive nature of the procedure long-term compliance is poor
 
Alprostadil was the first and until recently was the only licensed drug approved for intracavernous ED treatment.
- this treatment is effective in providing adequate erections - up to 80% of patients respond to treatment with intracavernosal alprostadil (1)
 - erection occurs typically 5-15 minutes after penile injection and frequently last 30-40 minutes, although the duration can be dose dependent.
 - contraindications include 
- history of hypersensitivity to alprostadil
 - a risk of priapism
 - bleeding disorders
 
 - requires training, reasonable manual dexterity and eyesight. Partner participation in the consultation and training programme can be valuable and improve long-term compliance.
 - a common side effect include 
- penile pain on injection (usually mild)
 - priapism may occur
 - penile fibrosis may occur - reported incidence varies from <1% to >20%. (1)
 
 
Papaverine has also been given by intracavernosal injection for impotence and is still used ‘off-license’ in some patients as monotherapy but it has more complications than alprostadil
- a combination prepaeration of papaverine and alprostadil may be useful due to reduce side effects by using a lower dose of each drug
 
Recently a combination of aviptadil (formerly known as vaso-intestinal polypeptide), and phentolamine (a short-acting alpha-adrenoreceptor antagonist that also has a direct effect on smooth muscle, causing relaxation) was approved and licensed in several European countries for ED.
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