Improving the duration of erection in males with ED

Considered as one of the most commonly occurring male sexual disorders, erectile dysfunction places a significant burden on male health and interpersonal relationships.1-6 Erectile dysfunction is considered a sentinel marker of underlying vascular abnormalities7-9 with approximately 70% of males with erectile dysfunction having coexisting hypertension, hyperlipidaemia, diabetes mellitus or depression.5

Dr Peter Lowy at the Sydney Centre for Men’s Health says erectile dysfunction is often a sign of another underlying or succeeding condition.

"It is a window into the body and often precedes other conditions, so we’re taking a much more aggressive look at a patient who presents with erectile dysfunction," said Dr Lowy.

"Inversely, if a patient comes in with diabetes, then you have to investigate beyond just this condition."

In addition, depression is often a co-existing condition, but can be treated simultaneously by treating an erectile dysfunction, according to Dr John Cherry at the Perth Human Sexuality Centre.

"Most often, when you successfully treat the erectile dysfunction, then you treat the depression," he says.

The three currently available pharmacological treatments for erectile dysfunction include:¹⁰

• Vardenafil (Levitra); 
• Sildenafil (Viagra); and
• Tadalafil (Cialis).

The regulatory approval of these PDE5 inhibitors was based on results obtained from patient diaries and questionnaires including:¹¹

• Erectile function domain of the International Index of Erectile Function (IIEF-EF);
• Sexual Encounter Profile (SEP); and
• Global Assessment question (GAQ): "Has the treatment you have been taking over the past 4 weeks improved your erections?"

The ENDURANCE study¹¹ is the first of its kind to incorporate the use of a novel stop watch assessment tool to measure the duration of erection. This was defined as the time from erection perceived hard enough for penetration until withdrawal from the partner’s vagina. The ENDURANCE study investigated the relative effectiveness of 10 mg vardenafil, compared with placebo, in increasing the duration of erection leading to successful intercourse.¹¹

Males aged 18–64 in a stable heterosexual relationship (> 6 months duration) and experiencing erectile dysfunction for more than 6 months (according to the National Institutes of Health Consensus Statement) were enrolled into the study. A number of exclusion criteria applied including premature ejaculation, penile anatomical abnormalities and surgical prostatectomy.¹¹

The study design included a 4-week treatment free period in which participants were instructed to attempt intercourse on four separate days. Those with greater than 50% unsuccessful attempts qualified for randomisation to either 10mg vardenafil (taken 60 minutes prior to attempting intercourse) or placebo for 4 weeks followed by a 1-week wash out period. Patients were then crossed over to receive the alternate treatment for the remainder of the study.¹¹

Dr Lowy says, in normal practice, the 10 mg dose of vardenafil prior to a sexual encounter is the regular treatment he prescribes in a clinical setting.

"The only time it really changes is if the patient is older, and then I may increase the dose to 20 mg," he says.

One hundred and seventy five of the 201 participants completed the study. The mean age of participants was 49 years of age with a 3.9 year mean duration of erectile dysfunction. Vardenafil resulted in a greater than two fold increase in the mean duration of erection leading to successful intercourse (p < 0.001). The mean difference between the two treatments was 7.36 minutes. In addition, patients reported a statistically significant improvement in erectile function with vardenafil compared to placebo. More patients answered "yes" to the question "Has the treatment you have been taking over the past 4 weeks improved your erections?" when treated with vardenafil compared to placebo (p < 0.001).¹¹

In a clinical interface, Dr Lowy says the study findings accurately represent the patients he sees from day to day.

"While I’m not sure of specificities, as it can vary from patient to patient, it is certainly prolonging the erection duration," he says.

Medication safety and patient tolerability were assessed on the basis of adverse events, clinical chemistry, haematology, urinalysis, 12-lead electrocardiograph (ECG) and vital signs. The majority of adverse events where mild–moderate with headache (3%) and flushing (5%) the most commonly reported. One patient discontinued treatment following an episode of moderate syncope while receiving vardenafil. There were no relevant effects of vardenafil on laboratory parameters, vital signs or ECGs.¹¹

Dr Lowy says he is not concerned about any serious side effects.

"There may be the usual headache or blocked nose as can happen with many medications, but there certainly isn’t anything serious."

The authors concluded that in a general population of men with erectile dysfunction vardenafil 10 mg produces a statistically superior duration of erection compared to placebo. The use of the stopwatch to assess erection duration as a primary efficacy endpoint was well correlated with currently accepted patient-reported outcome measures including the SEP and IIEF. This suggests that the stopwatch method is a reliable measure of erectile function and may be suitable for use in future efficacy trials.¹¹

While some may consider erectile dysfunction to be a man’s problem, it is a couple’s concern and effective treatment has the potential to restore both the man’s self esteem and the couple’s relationship.¹⁰

Dr Cherry says erectile function is tantamount to the mental health and well-being of any man.

"We have to remember the male is pelvically oriented, ever since they’ve been knee-high to a grasshopper," he says.

"Adequacy is totally intertwined with their personality, sexuality is about being able to get an erection, so it is also a symbol of manhood.

"So when that goes, depression can follow and self-esteem issues, so successful treatment is incredibly important for overall health."

For more information on erectile dysfunction, its types, causes and treatments, and tips for dealing with it, see Erectile Dysfunction.

References

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2. Rosen RC. Prevalence and risk factors of sexual dysfunction in men and women. Curr Psychiatry Rep. 2000; 2(3): 189-95.
3. McKinlay JB. The worldwide prevalence and epidemiology of erectile dysfunction. Int J Impot Res. 2000; 12(Suppl 4): S6-11.
4. NIH Consensus Conference. Impotence. NIH consensus development panel on impotence. JAMA. 1993; 270(1): 83-90.
5. Seftel AD, Sun P, Swindle R. The prevalence of hypertension, hyperlipidemia, diabetes mellitus and depression in men with erectile dysfunction. J Urol. 2004; 171(6 Pt 1): 2341-5.
6. Laumann EO, Paik A, Rosen RC. Sexual dysfunction in the United States: Prevalence and predictors. JAMA. 1999; 281(6): 537-44.
7. Thompson IM, Tangen CM, Goodman PJ, Probstfield JL, Moinpour CM, Coltman CA. Erectile dysfunction and subsequent cardiovascular disease. JAMA. 2005; 294(23): 2996-3002.
8. Jackson G. Erectile dysfunction: A marker of silent coronary artery disease. Eur Heart J. 2006; 27(22): 2613-4.
9. Jackson G, Rosen RC, Kloner RA, Kostis JB. The second Princeton consensus on sexual dysfunction and cardiac risk: New guidelines for sexual medicine. J Sex Med. 2006; 3(1): 28-36.
10. Jackson G. ENDURANCE: Getting the timing right. Int J Clin Pract. 2009; 63(1): 1-6.
11. Rosenburg MT, Adams PL, McBride TA, Roberts JN, McCallum SW. Improvement in duration of erection following phosphodiesterase type 5 inhibitor therapy with vardenafil in men with erectile dysfunction: The ENDURANCE study. Int J Clin Pract. 2009; 63(1): 27-34.