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Sildenafil Shows Highest Efficacy Among All Four Approved PDE5 Inhibitors in Dose-Specific Network Meta-Analysis
Across 83 randomized placebo-controlled trials enrolling 6,029 participants, sildenafil 100 mg demonstrated the highest odds of achieving satisfactory erectile function among all approved on-demand PDE5 inhibitors, with roughly nine times greater odds than placebo (OR 9.06). Vardenafil 10 mg and sildenafil 50 mg followed closely, while avanafil showed the more modest effect sizes, and tadalafil occupied an intermediate position depending on dose.
What Was Studied
This analysis examined whether four FDA- and EMA-approved phosphodiesterase-5 inhibitors (PDE5is) — sildenafil, tadalafil, vardenafil, and avanafil — differ meaningfully in their dose-specific efficacy when used on demand for erectile dysfunction. Prior meta-analyses had compared these agents at a class level but had not systematically disentangled outcomes by individual dose, leaving a gap in the evidence needed to differentiate clinical utility across the specific approved dosing options. The primary outcome was the proportion of participants achieving satisfactory erectile function, defined as an International Index of Erectile Function (IIEF) domain score exceeding 26.
How It Was Studied
Researchers conducted a systematic review and network meta-analysis (NMA), a method that allows indirect comparisons across treatments even when head-to-head trials are unavailable. Eligible studies were randomized, double-blind, and placebo-controlled, restricted to on-demand dosing regimens. In total, 83 trials were identified, encompassing 6,029 adult participants with erectile dysfunction — 3,457 in active treatment arms and 2,572 in placebo arms. A threshold analysis was additionally performed to test how robust the comparative rankings were to moderate variations in the underlying data, providing a secondary layer of confidence assessment beyond conventional confidence intervals.
What Was Observed
- Sildenafil showed the strongest association with achieving satisfactory erectile function at both approved doses. Sildenafil 100 mg was associated with approximately nine times greater odds than placebo (OR 9.06), and sildenafil 50 mg with nearly eight times greater odds (OR 7.90). Threshold analysis confirmed the robustness of these estimates, with sildenafil 100 mg retaining a statistically significant advantage even under moderate variation (OR 2.20; 95% CI 1.78–2.63) and sildenafil 50 mg similarly stable (OR 2.10; 95% CI 1.69–2.50).
- Vardenafil 10 mg performed comparably to higher sildenafil doses, with roughly 7.8 times greater odds of satisfactory erectile function versus placebo (OR 7.78), placing it second in the overall comparative ranking despite only one dose being represented in the analysis.
- Tadalafil showed a meaningful dose-dependent gap between its two approved on-demand strengths. Tadalafil 20 mg was associated with about seven times greater odds than placebo (OR 7.13), whereas tadalafil 10 mg showed considerably lower odds, roughly three times that of placebo (OR 3.14), suggesting a clinically relevant difference between doses within the same agent.
- Avanafil demonstrated the lowest efficacy estimates among the four agents, with avanafil 200 mg producing about 3.4 times greater odds than placebo (OR 3.42) and avanafil 100 mg showing only modest separation from placebo (OR 1.75). Regarding safety, vardenafil was associated with the highest odds of treatment-related adverse events, followed by avanafil and sildenafil, while tadalafil showed the lowest adverse event burden relative to placebo.
Why This Matters
Erectile dysfunction is recognized as a multifactorial condition involving vascular, hormonal, neurological, psychological, and systemic contributors, and PDE5 inhibitors represent the established first-line pharmacological approach. Despite multiple existing meta-analyses evaluating these agents, none had previously mapped efficacy across all four approved drugs at the level of individual doses. This dose-specific comparative framework enables more granular differentiation of the agents and provides a structured evidence base for understanding how dose selection within and across agents may influence clinical outcomes.
How to Read This Result
This high-quality network meta-analysis draws on a substantial number of placebo-controlled trials and finds a consistent positive signal for sildenafil’s comparative efficacy, though the wide confidence intervals observed for several comparisons — particularly in adverse event analyses — indicate meaningful uncertainty in some estimates that warrants interpretive caution.
Limitations
Wide confidence intervals were present for a number of comparisons within the network, particularly for adverse event outcomes, reflecting substantial variability across the included studies and limiting the precision of certain effect estimates. This uncertainty is most pronounced in the safety analyses and may affect the reliability of adverse event rankings between agents.