First-line medical therapy with a phosphodiesterase-5 enzyme (PDE-5) inhibitor is recommended because of its efficacy, favourable side-effect profile and ease of use.
ED FAST FACTS
- ED is the consistent or recurrent inability to acquire or sustain an erection of sufficient rigidity and duration for sexual intercourse
- Estimates suggest as many as 40% of men over 40 will deal with ED.
- Erection: Sexual stimulation releases nitric oxide (NO), which mediates the release of cyclic guanosine monophosphate (cGMP), which triggers smooth muscle relaxation and increases flow of blood into penile tissues, producing an erection.
- Sustained erection is dependent on cGMP levels (and other levels eg. NO)
- PDE-5 selectively hydrolyses cGMP
- ED can be a warning sign of silent vascular disease or diabetes.
TREATMENT OF ED
Take a thorough patient history to help identify cause: organic (eg low testosterone levels, underlying cardiovascular disease or neurogenic cause), drug-induced, psychosocial or combined.
- First-line treatment = alter modifiable risk factors and causes
- Second-line treatment = PDE-5 inhibitors, counselling and education
- Third- line treatment = alprostadil injections (prostaglandin E1)
- Fourth-line treatment = surgical treatment (penile implants).
Treatment with PDE-5 inhibitors is not considered a failure until full dose is trialled seven to eight times. According to Marais (2015) of the University of Pretoria, ED is a common condition and is vastly undertreated. Association with an increased risk of cardiovascular disease and mortality should make physicians more vigilant and proactive in managing ED. Serum testosterone levels should be regularly checked in men with features of metabolic syndrome and ED.
Stigma around the condition should be eliminated by proper education. Patients should be encouraged to report any symptoms to their healthcare provider, including primary care workers and pharmacists. Levine (2003) found that sildenafil has a duration of action of about four hours. Vardenafil’s duration of action is similar, but tadalafil’s is substantially longer, approaching 36 hours. According to Wrishko et al (2009), the following patients would benefit from tadalafil, due to its duration of action: those for whom planning, and timing of treatment undermines their sexual satisfaction, those whose partners tend to initiate sex, and those whose natural sexual pattern includes a time interval from first sexual thought to sexual activity.
In a study by Tolrà et al (2006), of 132 patients, 52% patients who chose tadalafil above sildenafil (27%) and vardenafil (20%), because they stated that it was the one that enabled them to achieve a more intense and longer-lasting erection. Three patients chose it because of the flexibility it provided them by being able to take it at any time of the day (not dependant on food consumption). For five participants, the feeling that they could have intercourse again the following day, even if they ended up not doing so, was what tipped the scale in favour of tadalafil.
References available on request.