Sildenafil
Viagra · PDE5 inhibitor
What it is
The original erectile-dysfunction drug — shorter-acting than tadalafil (~4-hour window vs ~36); also prescribed for pulmonary hypertension.
What human evidence shows
Among the best-evidenced drugs in this file — large RCTs, decades of use. The effect on erectile function is robust. Off-label cosmetic or training uses have no suitable trial evidence.
Risks
Headache, flushing, congestion, visual tinting; serious interactions with nitrates (dangerous blood-pressure drops) and caution with alpha-blockers. Rare but real: priapism, sudden hearing/vision events. Counterfeit tablets are a well-documented problem and often contain unlisted doses of the real drug.
Legal status
US: prescription-only.
Evidence base
established literature
Large human evidence base: several phase 3 or 4 trial reports, plus multiple meta-analyses or systematic reviews.
- phase 3/4
- 13
- randomised
- 727
- reviews
- 233
- human trials
- 1,055
Counts are of published papers, not distinct trials, and measure how much research exists — not whether this works or is safe for you.
Research (12)
- Sildenafil/Viagra in the treatment of premature ejaculationInt J Impot Res · 2019
- Direct comparison of tadalafil with sildenafil for the treatment of erectile dysfunction: a systematic review and meta-analysisInt Urol Nephrol · 2017
- Sildenafil in Combination Therapy against Cancer: A Literature ReviewCurr Med Chem · 2021
- Sildenafil's impact on male infertility: what has changed in 20 years?Int J Impot Res · 2019
- Sildenafil does not reliably improve exercise performance in hypoxia: a systematic reviewBMJ Open Sport Exerc Med · 2019
- A Systematic Review of Sildenafil Mortality Through the YearsCureus · 2022
- Sildenafil beyond erectile dysfunction and pulmonary arterial hypertension: Thinking about new indicationsFundam Clin Pharmacol · 2021
- Sildenafil-associated hepatoxicity: a review of the literatureEur Rev Med Pharmacol Sci · 2017
- Sildenafil in dialysis patientsInt J Artif Organs · 2006
- Exploring the Multifaceted Potential of Sildenafil in MedicineMedicina (Kaunas) · 2023
- Sildenafil in Term and Premature Infants: A Systematic ReviewClin Ther · 2015
- Viagra (sildenafil citrate) and ophthalmologyProg Retin Eye Res · 2002
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