Erectile Dysfunction: Treatment of Impotence
Review literature: (Lue, 2000) (Porst, 2004).
Medical and Conservative Treatment of Erectile Dysfunction
The renunciation of smoking, regular exercise, only moderate amounts of alcohol and a healthy diet can prevent the development of erectile dysfunction. A change in lifestyle in midlife with manifest erectile dysfunction is, however, often too late and has little therapeutic value in regard of erectile function within months. If a change in lifestyle is maintained over years, vascular changes are partly reversible and erectile dysfunction may improve (Esposito et al, 2004). Improvement in erectile dysfunction can also be expected in alcoholics with abstinence. The change of a medication with side effects on erectile function is a good option for improvement of ED, if the cardiological or neurological safety is maintained.
Physiotherapy and Sex Therapy
Physiotherapy (pelvic floor exercises) may show a therapeutic effect in erectile dysfunction due to mild venous insufficiency.
Sex therapy for erectile dysfunction is a therapeutic option in psychogenic erectile dysfunction, especially in young men. Because of the frequency of the disease, there is no capacity to offer sex therapy to all men with psychogenic erectile dysfunction. In the long-term, the success of sex therapy is poor (success rates of less than 50%).
Androgen Deficit of the Aging Male (ADAM)
Testosterone substitution should be considered in hypogonadism and erectile dysfunction. The effect of testosterone substitution on erectile function is only moderate, but improved libido and better effectiveness of oral drugs can be expected. Hypogonadism is frequently associated with a metabolic syndrome, testosterone substitution improves several parameters of the metabolic syndrome. Whether a long-term androgen therapy shows a benefit for the patients in regard of overall survival remains to be proven. Over the long term, risks of testosterone supplementation is poorly understood.
Other drugs as L-carnitine or DHEA are also used in the treatment of erectile dysfunction with symptoms of ADAM, however, there are no supporting controlled trials.
Phosphodiesterase type 5 (PDE5) Inhibitors
Phosphodiesterase type 5 (PDE 5) inhibitors have simplified the treatment of erectile dysfunction. PDE5 inhibitors offer, compared to other orally active drug, a superior efficacy. The success rates of PDE 5 inhibitors (successful sexual intercourse) is around 70-75% in patients with ED and with maximal dosage. The market share of new PDE5 inhibitors (vardenafil, tadalafil) is increasing to the expense of sildenafil. Tadalafil has a longer mechanism of action and is marketed as "weekend pill". Vardenafil has a faster onset of action and a favorable side-effect spectrum. General mechanisms of action, side effects and pharmacokinetics see section phosphodiesterase type 5 inhibitors. Dosage of PDE 5-inhibitors:
- Sildenafil: dosage 25 mg, 50 mg and 100 mg. Onset of action: 30–60 min. Duration 4–6 h.
- Vardenafil: dosage 10 mg and 20 mg. Onset of action: 30–60 min. Duration 4–8 h.
- Tadalafil: dosage 10 mg and 20 mg. Onset of action 60–120 min. Duration 12–36 h
Other Drugs used against Erectile Dysfunction
Due to the efficiency of PDE 5-inhibitors, drugs listed below have a minor role in treating erectile dysfunction.
Treatment of Hyperprolactinemia
Hyperprolactinemia is treated with oral dopamine agonists like cabergoline or bromocriptin.
Yohimbine is a competitive α-adrenergic antagonist with effect on the CNS. Yohimbine promotes erection by central mechanisms. Yohimbin has only effect in patients with psychologic or minor organic erectile dysfunction, since for the mechanims of action an organically intact erectile tissue and innervation is necessary. Dosage: 3 days starting on 3 × 5 mg p.o., afterwards 3 × 10 mg p.o.
Side effects of yohimbine: gastrointestinal symptoms, palpitations, headache, agitation, anxiety, hypertension (Cave: cardiovascular diseases).
Apomorphine is a dopaminergic agonist who activates D1 and D2 receptors in the hypothalamus (paraventricular nucleus, medial area praeoptica ...), a center of sexual desire. Apomorphine shows a dose-dependent effect: 2 mg vs. Placebo (46% vs. 32%), 4 mg vs. Placebo (52% vs. 35%) and 6 mg vs. Placebo (60% vs. 34%). However, this applies also nausea, the main side effect: 2%, 22% and 41% for 2, 4 and 6 mg. Other side effects: dizziness, vomiting, sweating, fatigue, syncope (very rare).
Apomorphine can be administered sublingually. An indication for apomorphine are patients with contraindications to PDE 5-inhibitors (e.g. nitrate therapy).
Trazodone is a non-tricyclic antidepressant with therapeutic effect in erectile dysfunction, especially in patients with depression or psychogenic erectile dysfunction. Dosage 50–150 mg/d.
Doxazosin is an α-blocker, which is used in patients with LUTS and erectile dysfunction.
Only a moderate effect could be demonstrated in randomized trials for the efficiancy of topical treatment (creams, etc.) . At least in psychogenic erectile dysfunction, this is an interesting therapeutic option. The following drugs are used for topical treatment in erectile dysfunction: testosterone, vasoactive substances such as prostaglandins, ergotamine or nitrates.
Effective natural products:
The following natural products showed efficiency in erectilye dysfunction in randomized trials: Butea superba, Korean Ginseng.
Treatment of Erectile Dysfunction with Intracavernosal Injections and Devices
Intracavernosal Injection Therapy
The indications for intracavernosal injections (ICI) are patients with poor efficacy of oral therapy or contraindications to PDE 5-inhibitors. In diagnostic ICI, the dose of alprostadil (prostaglandin E1
) is determined, which usually lies between 5 and 20 mg alprostadil. After instruction of the patient in the technique of ICI, success rates of 94% have been reported.
Side effects of intracavernosal injections: painful injection, which can be avoided by slow injection. 5% prolonged erection, 1% risk of priapism. Fibrosis of the erectile tissue 2%. hematoma 8% .
If ICI with alprostadil shows no or not enough response, intracavernosal injections are possible with papaverine (opium alkaloid) and/or phentolamine (α-blocker). Either can be given alone or in combination, the side effect spectrum is considerably higher.
Transurethral administration of Alprostadil (MUSE)
Transurethral administration of alprostadil in form of a gel is an effective treatment option, which is helpful in patients with fear of intracavernosal injections. The abbreviation MUSE stands for Medicated Urethral System for Erection. The effectiveness is controversial.
Vacuum Constriction Device for Erectile Dysfunction
Vacuum therapy uses a plastic cylinder, which is placed over the penis and sealed at the base. By creating a vacuum with a hand pump, the penis is filled passively with blood untill an erection is reached. After removal of the cylinder, the erection is maintained with the help of a penis ring at the base of the penis.
There is good objective success rate of vacuum therapy, which can be improved with the combination of vacuum therapy with intracavernosal injections or PDE 5-inhibitors. The high rate of side effects (pain, difficult ejaculation, ecchymosis) and the availability of effective alternative lead to an acceptance rate of only 30–70%.
Surgical Therapy of Erectile Dysfunction
Ligation of the Penile Veins:
The ligation of penile veins (most common dorsal veins of the penis) is indicated in venous insufficiency of isolated veins due to trauma or congenital diseases. Suitable patients are young with no evidence of arterial insufficiency. The diagnostic work-up should include Doppler sonography with intracavernosal injection and Cavernosographie. The dorsal penile veins are exposed via an infrapubic incision an the dorsal veins are ligated at the base of the penis. Crural veins are exposed via a perinal incision. Due to the low morbidity, ligation of penile veins is therapeutic option is selected young patients. In older patients with veno-occlusive dysfunction, moderate to disappointing results are realistic.
Penile Arterial Revascularization:
Indications for penile revascularization exist in young patients with isolated arterial stenosis of extrapenile arteries and lack of efficacy with intracavernosal injections. Venous insufficiency should be excluded before revascularization. Poor results are to be expected in patients with diabetes mellitus or peripheral arterial disease. There are different surgical procedures, general complications are shunt occlusion, hyperemia of the glans and poor long-term results (30-40%).
Michal I procedure:
Anastomosis of the inferior epigastric artery with the Corpus cavernosum. Historic procedure, is not performed any more.
Michal II procedure:
Anastomosis of the inferior epigastric artery with the dorsal penile artery.
Anastomosis of the inferior epigastric artery with the vena dorsalis penis, acceptable long-term results.
Anastomosis of the inferior epigastric artery simultaneously with dorsal penile artery and vein (AV-fistula). The high blood flow in the AV-fistula prevents a thrombosis of the anastomosis. Acceptable long-term results.
Penile prothesis for treatment of erectile dysfunction are indicated after failure of intracavernosal injection or vacuum therapy in motivated patients. Patients have to be advised about the different prothesis systems including costs and technical differences, surgical risks (infection, perforation) and possible mechanical failure. letzter Satz auch ins deutsche.
Malleable (semiregide) penile prosthesis:
Advantages of semirigid penile prosthesis are the easy implantation, low risk of mechanical failure and low costs. The disadvantage is the permanent semiregide erection, which can bother in everyday life.
Inflatable penile prostheses:
The basic structure of the inflatable penile prosthesis is similar to an artificial urinary sphincter and consists of a three-piece construction: paired penile cylinders as implant for the corpus cavernosum, fluid reservoir and a scrotal pump (inflatable penile prothesis AMS 700). The advantage of inflatable prosthesis is the better functionality, disadvantages are the costs and the risk of mechanical failure.
Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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Linkenheim-Hochstetten : Aesopus Verlag, 2004