Erectile Dysfunction


patients in the finasteride group. The prevalence of decreased libido and ejaculatory disorders was significantly higher in patients treated with finasteride than in those taking placebo.9


In a meta-analysis


conducted by the American Urological Association (AUA) BPH guidelines committee, ED was the most common adverse effect identified, with a rate of 8% in the finasteride group compared with 4% in the placebo group.10


Finasteride also showed a significantly higher rate of these adverse effects compared with α1-blockers.11


Similar incidences of sexually related adverse events have been reported for dutasteride.12


One group that evaluated the efficacy of


dutasteride reported rates of 7.3% for ED (4% placebo), 4.2% for decreased libido (2.1% placebo) and 2.2% for ejaculatory dysfunction (0.8% placebo).13


dutasteride found similar incidences of sexual adverse effects.5


Sexual adverse events occur most frequently early in therapy and appear to decline over time in patients using dutasteride or finasteride. A phase III multicentre, randomised, placebo-controlled trial lasting for four years identified initial rates of sexual adverse effects to be 6.1% in dutasteride-treated patients, a rate that decreased with time.12


Alpha-blockers


A variety of α-ABs are available and all are selective inhibitors of α1 receptor activity. Their use generally results in a 6–31% improvement in symptom score within the first two to three weeks of treatment.14,15


A meta-analysis conducted by the AUA found that sexual erectile problems appeared in 3–5% of patients and decreased libido in 1–3% of patients.10


The α1-adrenergic receptor antagonists have no antiandrogenic effect and generally no negative effects on sexual desire or erectile function.8


Moreover, a study comparing finasteride and


In an observational study, men taking α1A-subtype non-superselective α-ABs appeared to have better erectile function than men taking 5-ARIs and better ejaculatory function than men taking the


α1A-subtype superselective α-AB tamsulosin, 5ARIs or α-ABs plus 5ARI combination therapy.21


Combination Therapy Combined therapy with 5-ARIs and α-1-ABs is recommended for patients with moderate to severe LUTS and a demonstrably enlarged prostate. However, combined therapy carries a larger cumulative risk of developing sexual adverse effects compared with the risk observed with either drug alone.9


In trials evaluating combination BPH treatment, sexual adverse effects were the most commonly reported drug-related side effects.22


It is not


clear whether combination therapy is associated with an increased rate of sexual adverse effects compared with 5-ARIs in monotherapy. In the MTOPS study, the frequency of ED in the combination-therapy group (doxazosin plus finasteride) was similar to that of the finasteride group, although abnormal ejaculation was more frequent.9


In the Combat study, the incidence of ED for the combined therapy (dutasteride and tamsulosin) was higher (9%) than that for either dutasteride (7%) or tamsulosin (5%) in monotherapy. RE and decreased libido also were more frequently reported for the combination therapy.23


Surgical Treatment


Presumed retrograde ejaculation (RE) is the most prevalent manifestation of the ejaculatory disorders, probably


Despite this, several clinical trials have demonstrated that this treatment is associated with an increased abnormal ejaculation rate (4–11% of patients).8


through the relaxing effect of α1-adrenergic receptor antagonists on the bladder neck. In addition, α1-adrenergic receptor blockade in the vas deferens, the seminal vesicles or the prostate might lead to a reduced or absent ejaculate volume.8


Terazosin and doxazosin are non-subtype-selective, although tamsulosin and alfuzosin are functionally uroselective. Tamsulosin is


the most potent adrenergic α1-antagonist used for treating BPH, with a uroselectivity 10 times greater than the non-selective drugs.16 Men treated with tamsulosin tend to preserve their sexual function better than similar populations treated with other non-selective α1-blockers,17


but for this uroselectivity tamsulosin is associated with


the highest reported rate of RE among all α-blockers, at 6% with the standard dose.18


Despite this effect on ejaculatory function in a minority of patients, several studies have shown a beneficial effect of α-ABs on overall sexual functioning.19


One hypothesis is that the improvement in sexual function is a consequence of a pharmacological effect


through the blockade of α1-adrenergic receptors in the penile arteries and/or corpora cavernosa.14


Contraction of penile smooth muscle, which results in retaining the penis in the flaccid state, is maintained


by the action of noradrenaline on α1-adrenergic receptors. Thus, blockade of these receptors by α1-blockers might result in


52


There are several surgical options for BPH treatment. These range from less invasive techniques such as transurethral incision of the prostate to more aggressive options such as transurethral resection and open prostatectomy. Surgical treatment for BPH can cause undesirable changes in sexual function. Likewise, it has long been postulated that ED is a side effect of prostate surgery.24


Reported


rates of ED range widely depending on the study and the methodology used for detection.25


Data suggest that post-operative impotence can be temporary and may improve with time.26


However, it has been reported that


prostatectomy affects sexual function to no greater extent than other operations of the same severity on patients of the same age.27 Nevertheless, differences have been found in ED between subjective patient reports and objective impotence tests such as nocturnal penile tumescence monitoring. In many cases, the patient claims to be impotent while nocturnal penile tumescence recording indicates normality.28


smooth-muscle relaxation and increased blood flow into the lacunar spaces of the corpora cavernosa, improving erectile function.20


There have been attempts to explain the high rate of self-reported ED based on the fact that patients may consider RE to represent ED. Two-thirds of patients who claim ED actually have RE when interviewed correctly.29


A few risk factors are associated with post-operative ED. In several studies, older age appeared to constitute an adverse factor by increasing the risk.26,30


Another associated risk has been reported to


be surgery on small prostates, perhaps because of the greater proximity of the neurovascular bundles to the surgical site. This factor may account for the finding that capsular perforation, particularly of the posterior area, is associated with an increased probability of post-operative ED.31,32


EUROPEAN UROLOGICAL REVIEW


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