ORIGINAL RESEARCH—PHARMACOTHERAPYThe Efficacy of Tadalafil in Clinical Populations
Introduction
Erectile dysfunction (ED) has become recognized as a significant health issue in a large percentage of men over the age of 40 years [1]. A number of factors can contribute to the development of ED, including aging, cardiovascular disease, diabetes, smoking, anxiety and/or depression, certain drugs including antidepressants and antipsychotics [2], and a variety of other organic or psychological factors [3, 4, 5]. Awareness of ED increased with the approval in 1998 of sildenafil citrate, an oral treatment that improves erectile function in men having ED of various etiologies [6, 7].
Tadalafil and sildenafil are inhibitors of phosphodiesterase type 5. Tadalafil primarily differs from sildenafil by having a duration of efficacy lasting up to 36 hours after a single dose compared with about 4 hours for sildenafil [8, 9], although a recently published small open‐label study in sildenafil responders suggested that sildenafil 100 mg might be effective in some men up to 12 hours after dosing [10]. Tadalafil has been shown to be efficacious and safe in a large number of patients with ED including men with diabetes mellitus [11, 12, 13, 14]. Additionally, a recent study demonstrated that tadalafil significantly improved erectile function in men with ED following bilateral nerve‐sparing radical retropubic prostatectomy [15]. In this article, 11 double‐blind placebo‐controlled trials were integrated and analyzed to determine the effectiveness of tadalafil in improving erectile function in more than a dozen clinical subpopulations.
Section snippets
Study Design
Data collected from 11 randomized, double‐blind, placebo‐controlled, parallel trials conducted worldwide at 174 centers in 18 countries from April 1999 to February 2003 were used in all of the analyses (Table 1). Details regarding the general study design, efficacy and safety measures, and statistical analysis were published previously [12, 13]. Patients were randomized to 12 weeks of treatment with placebo (N = 638) or tadalafil at fixed doses including 10 mg (N = 321) or 20 mg (N = 1,143)
Demographic and Baseline Characteristics
Demographic and baseline illness characteristics are shown in Table 2. The mean age was 56 years (range, 22–88 years) with most patients (88%) having ED for at least 1 year. The proportion of patients with mild, moderate, or severe ED was similar in all three treatment groups (P = 0.933). Hypertension (29%), diabetes mellitus (20%), and hyperlipidemia (16%) were common comorbid conditions.
The vast majority of patients taking tadalafil (10 mg, 88.5%; 20 mg, 89.7%) and placebo (86.8%) completed
Discussion
This analysis of 2,102 men with ED demonstrated that tadalafil 10 mg and 20 mg were effective in all clinical populations analyzed, including in patients with diabetes mellitus, who are considered difficult to treat. Tadalafil 20 mg showed numerically greater improvement than tadalafil 10 mg for each efficacy measure in most of the clinical populations.
Tadalafil showed improved efficacy among all racial groups. It would have been more informative if the number of Hispanics and patients of
Conclusions
The findings from this 11‐study integrated analysis of 2,102 men with ED demonstrate that tadalafil is effective in improving erectile function across a variety of patient demographics and illness characteristics including ED etiology, severity and duration, and comorbid conditions and treatments. Tadalafil also proved to be effective in the subpopulation of men with diabetes mellitus and ED, who are difficult to treat.
Conflict of Interest
Wei Christine Wang, Wei Shen, Daniel J. Walker, David G. Wong, and Sanjeev Ahuja are employees of Eli Lilly and Company.
References (39)
- et al.
Construction of a surrogate variable for impotence in the Massachusetts Male Aging Study
J Clin Epidemiol
(1994) - et al.
Epidemiology/risk factors of sexual dysfunction
J Sex Med
(2004) - et al.
The efficacy of sildenafil citrate (Viagra) in clinical populations: An update
Urology
(2002) - et al.
Efficacy of sildenafil citrate at 12 hours after dosing: Re‐exploring the therapeutic window
Eur Urol
(2004) - et al.
Efficacy and safety of tadalafil for the treatment of erectile dysfunction: Results of integrated analyses
J Urol
(2002) - et al.
Tadalafil in the treatment of erectile dysfunction following bilateral nerve‐sparing radical retropubic prostatectomy: A randomized, double‐blind, placebo‐controlled trial
J Urol
(2004) - et al.
The international index of erectile function (IIEF): A multidimensional scale for assessment of erectile dysfunction
Urology
(1997) - et al.
Diagnostic evaluation of the erectile function domain of the International Index of Erectile Function
Urology
(1999) - et al.
Impotence and its medical and psychosocial correlates: Results of the Massachusetts Male Aging Study
J Urol
(1994) - et al.
Efficacy and tolerability of vardenafil for treatment of erectile dysfunction in patient subgroups
Urology
(2003)
Erectile dysfunction and coronary risk factors: Prospective results from the Massachusetts Male Aging Study
Prev Med
The prevalence of hypertension, hyperlipidemia, diabetes mellitus and depression in men with erectile dysfunction
J Urol
Modifiable risk factors and erectile dysfunction: Can lifestyle changes modify risk?
Urology
Lower urinary tract symptoms and erectile dysfunction: Co‐morbidity or typical “Aging Male” symptoms? Results of the “Cologne Male Survey.”
Eur Urol
Lower urinary tract symptoms and male sexual dysfunction: The Multinational Survey of the Aging Male (MSAM‐7)
Eur Urol
One‐year follow‐up of 2829 patients with moderate to severe lower urinary tract symptoms treated with alfuzosin in general practice according to IPSS and a health‐related quality‐of‐life questionnaire. BPM Group in General Practice
Urology
Current drug use as risk factor for erectile dysfunction: Results from an Italian epidemiological study
Int J Impot Res
Definitions, classification and epidemiology of sexual dysfunction
Epidemiology of erectile dysfunction
Int J Impot Res
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