#245 Taking a hard look at the evidence: Phosphodiesterase-5-inhibitors in erectile dysfunction
CLINICAL QUESTION
What is the efficacy and safety of phosphodiesterase-5-inhibitors (PDE5 inhibitors) for erectile dysfunction?
BOTTOM LINE
PDE5 inhibitors increase the proportion of successful sexual intercourse attempts to ~65% versus ~30% for placebo. For every 3 men given a PDE5 inhibitor compared to placebo, an additional 1 will have “improved erections”.
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EVIDENCE
All results statistically significant unless indicated.
- Systematic review, 130 randomized controlled trials (RCTs) of most PDE5 inhibitors (sildenafil, vardenafil, tadalafil, mirodenafil, udenafil), over 30,000 patients with erectile dysfunction of any cause.1,2 After ~12 weeks:
- Proportion of successful sexual intercourse attempts (erection sufficiently hard and long lasting for satisfactory intercourse):
- ~65% versus ~30% (placebo).
- Proportion of patients with self-reported “improved erections” using PDE5 inhibitors:
- ~78% versus 31% (placebo), Number Needed to Treat (NNT)=3.
- Proportion of successful sexual intercourse attempts (erection sufficiently hard and long lasting for satisfactory intercourse):
- Systematic review, 118 RCTs, n=31,195, all PDE5 inhibitors:3
- Proportion of patients with “improved erections”: ~79% versus ~29% (placebo); NNT=2.
- Systematic review, 8 RCTs, n=1759, men with diabetes:4
- Proportion of patients with “improved erections”: ~58% for PDE5 inhibitors versus ~15% placebo; NNT=3.
- Adverse effects:
- Any adverse event:1 ~44% versus ~24% (placebo), mainly headache, flushing, dyspepsia.
- Withdrawal due to adverse effects: Sildenafil5, vardenafil2 not different from placebo, tadalafil 1.6-3.2% versus 1.3% placebo5, number needed to harm=52-333.
- Limitations:
- Majority of RCTs unclear randomization concealment/blinding methods.1,6,7
- Many RCTs industry supported.1,2
- Other systematic reviews inadequately reported symptom scores or used scales with limited clinical meaning.5,6,8,9
- Prevalence of erectile dysfunction is ~30-50% in men aged 40–70; increases with age and comorbidities.1,5
- Contraindicated with concurrent nitrate use.2
- All PDE5 inhibitors: $50-$65 for 4 tabs (or $13-$16/tablet independent of dose) and not generally covered by public drug plans.10
- Cost may be reduced by pill splitting.
- On-demand versus daily dosing of tadalafil: no clinically meaningful difference in change of erectile function and no difference in adverse event discontinuation rates.6,7
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