Erectile Function, Erection Hardness and Tolerability in Men Treated With Sildenafil 100 mg vs. 50 mg for Erectile Dysfunction

M. Kirby; D. L. Creanga; V. J. Stecher

Disclosures

Int J Clin Pract. 2013;67(10):1034-1039. 

In This Article

Results

The five fixed-dose DBPC studies contained more than 1500 men who were enrolled and received at least one dose of placebo (n = 619), sildenafil 50 mg (n = 522) or sildenafil 100 mg (n = 523), for whom the mean ages were 56 years, 57 years and 56 years, respectively, with more than 85% of each treatment group aged ≥ 45 years. Most of the men (88%) were white. At the time of enrolment, ED had persisted, on average, for 4.3 years; it was most frequently organic in origin. The most common concomitant illnesses were of cardiovascular aetiology or associated with cardiovascular risk factors [i.e. hypertension, diabetes mellitus (non-insulin dependent), hypercholesterolaemia/hyperlipidaemia, ischaemia heart disease and a history of myocardial infarction]. Benign prostatic hyperplasia and a history of localised prostate cancer were also relatively common, as were other conditions associated with an elderly or ageing population (e.g. osteoarthritis, gastroesophageal reflex disease, depression and visual disturbance). Thus, the DBPC database includes a heterogeneous ED population that is representative of the ED population as a whole.

Erectile Function

Across all five DBPC studies that assessed a fixed dose of sildenafil 50 mg and a fixed dose of sildenafil 100 mg, and measured the change in the IIEF-EF score from baseline to the end of 8–12 weeks of DBPC treatment, improvements were significantly greater for both doses compared with those for placebo (p < 0.0001). In each trial, there was a larger improvement in the IIEF-EF score in the 100-mg sildenafil group than in the 50-mg sildenafil group, but the difference between doses was not statistically significant for any of the individual studies (Table 1).

Data were pooled for studies 148–106 and 148–361 because they had similar study designs. The improvement from baseline in the IIEF-EF score was significantly greater in the 100-mg sildenafil group than in the 50-mg sildenafil group (10.7 ± 0.64 vs. 8.9 ± 0.83, p = 0.0287).

Erection Hardness

In both DBPC studies that assessed a fixed dose of sildenafil 50 mg and a fixed dose of sildenafil 100 mg, and measured EHS at week 2 and at week 8, the odds of achieving EHS4 erections were several times greater for the sildenafil dose groups than for the placebo group [range of odds ratios (OR) across studies, dose groups and assessment times = 4.45–18.52, p < 0.001]. In general, the odds of achieving EHS4 erections were greater for the 100-mg group compared with the 50-mg group, significantly so during the first 2 weeks of treatment in one of the two studies in which assessment at this time point was conducted (Table 2). During the first 2 weeks of treatment in this study, the odds of achieving EHS4 erections were almost doubled for the 100-mg group compared with the 50-mg group [OR = 1.77 (95% CI, 1.03–3.06); p = 0.0398]. Differences in outcomes between the two studies could have been influenced by clinical research variation in patient populations.

Tolerability

Common treatment-related adverse events in men treated with sildenafil were those related to the pharmacology of PDE5 inhibition, such as headache and flushing (Table 3). These were reported in a higher incidence of men treated with sildenafil than with placebo.

Except for an increased incidence of headache, dyspepsia and visual disturbance at the 100-mg dose compared with the 50-mg dose, the tolerability profiles of sildenafil 100 mg and 50 mg in the DBPC studies were generally comparable (Table 3). Indeed, for some adverse events, the incidence was slightly higher among those receiving 50 mg than among those receiving 100 mg. For example, flushing [16% (50 mg) vs. 14% (100 mg)] was more prevalent in the lower dose group.

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