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Sildenafil and erectile dysfunction in diabetes

Study
Outcomes
Results
Adverse effects
Comment

Bandolier 53 reported on some of the first trials of sildenafil (Viagra). Those trials recruited patients with erectile dysfunction caused by a range of conditions. Only about 14% of the men had diabetes. A new report [1] concentrates on men with diabetes.

Study


It was conducted in 268 men with a mean duration of erectile dysfunction of 5.6 years with type I or type II diabetes with a mean duration of 12 years since diagnosis. The mean age was 57 years with a range of 27 to 79 years.

The study was properly randomised and double blind, and compared sildenafil against placebo over 12 weeks. The sildenafil dose was 50 mg initially, but could be increased to 100 mg or decreased to 25 mg. There were various obvious exclusions. Men with haemoglobin A1c values of more than 12% and a fasting plasma glucose of more than 16.6 mmol/L before the trial started were excluded.

Outcomes


The basic method used in the sildenafil study was that of a self-administered measure of erectile dysfunction, the international index of erectile dysfunction (IIEF) which was detailed in Bandolier 53 . Results on efficacy were taken from questions 3 ("When you attempted sexual intercourse, how often were you able to penetrate your partner?") and question 4 ("During sexual intercourse, how often were you able to maintain an erection after you had penetrated your partner?") of the IEFF index.

Results


At baseline, and after 12 weeks with placebo, the mean responses to questions 3 and 4 were at the level of "much less than half the time". After 12 weeks with sildenafil the mean responses were above the level of "about half the time". This response rate was similar to that of 50 mg of sildenafil found in the earlier studies ( Bandolier 53 ).

Successful sexual intercourse was reported by 48% of men on sildenafil and 12% of men on placebo during the last four weeks of treatment. Improved erections were reported by 74/131 men on sildenafil and 13/127 patients taking placebo. This gives a number needed to treat of 2.2 (95% confidence interval 1.8 to 2.8)

Adverse effects


More men taking sildenafil reported headache (11%) and dyspepsia (9%), as well as some respiratory tract disorders (6%), flushing (4%), rhinitis (4%) and abnormal vision (4%). Adverse effects were found in 22/136 men on sildenafil and 1/132 men taking placebo. The number needed to harm was 6.5 (4.6 to 11). Cardiovascular adverse effects occurred in 4/136 men on sildenafil and 6/132 men taking placebo.

Comment


The results for men with diabetes (predominantly type II) were much the same as those in men with other causes of their erectile dysfunction ( Bandolier 53 ). The effectiveness of sildenafil was much the same irrespective of age, duration of erectile dysfunction or duration of diabetes.

Reference:


  1. MS Rendell et al. Sildenafil for treatment of erectile dysfunction in men with diabetes. JAMA 1999 281: 421-426.

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