At a glance
Effects
- Erectile function: Facilitates and sustains erection in response to sexual stimulation by prolonging cGMP-mediated smooth muscle relaxation in the corpus cavernosum [3].
- Pulmonary vasodilation: Reduces pulmonary arterial resistance by relaxing vascular smooth muscle via NO–cGMP pathway; approved for PAH management [4][5].
- Systemic vasodilation: Causes mild, dose-dependent lowering of systemic blood pressure due to PDE5 expression in peripheral vasculature [2][6].
- Improved endothelial function: PDE5 inhibition increases cGMP and improves endothelial function across multiple vascular beds [2].
- Possible cardiovascular remodelling: Emerging research suggests sildenafil may promote collateral artery growth (arteriogenesis) in cardiovascular occlusive disease models [6].
PDE5 inhibitor
~4 hours (sildenafil + active metabolite) [4][9]
Oral (tablet / orodispersible film) [4]
30–60 min (peak plasma ~60 min fasted) [4]
Up to ~4–6 hours clinically [2]
About Sildenafil
Every point here is drawn from public medical and harm-reduction sources. A bracketed number after a claim — like [1]— is a reference: tap it to open the exact source it's based on (numbered list at the bottom). It is not a rating or score. Educational information, not medical advice.
Product specifics
- Est. delivery
- 3–7 business days · EU tracked
Product details as stated by the vendor (claims, not independently verified). Delivery is our standard EU estimate.
What it is
Sildenafil (brand names Viagra® and Revatio®) is a phosphodiesterase type 5 (PDE5) inhibitor used medically to treat erectile dysfunction (ED) and pulmonary arterial hypertension (PAH) [1][2]. It is the original and most widely recognised drug in its class, acting selectively on vascular smooth muscle to increase blood flow [3].
How it works
Sexual stimulation triggers the release of nitric oxide (NO) in the corpus cavernosum; NO activates guanylyl cyclase, producing cyclic GMP (cGMP), which relaxes smooth muscle and allows arterial blood inflow to produce an erection [3]. PDE5 is the enzyme that normally breaks cGMP down and terminates erection. Sildenafil competitively inhibits PDE5 (IC₅₀ 3.5 nM), preventing cGMP degradation and amplifying the NO signal — but only when sexual stimulation is present [1][3]. In pulmonary vasculature, the same mechanism causes smooth muscle relaxation, lowering pulmonary artery resistance [2][4].
Risks & side effects
Most important: The single most critical risk is severe — potentially fatal — hypotension when sildenafil is combined with any organic nitrate (e.g. nitroglycerin, isosorbide, recreational 'poppers'): nitrates raise cGMP while sildenafil blocks its breakdown, producing a synergistic blood pressure crash [7][8]. This combination is an absolute contraindication; no safe interval shorter than 24 hours exists after a sildenafil dose [7].
Common
Serious
- Severe hypotension — especially in combination with nitrates or alpha-blockers [7][8]
- Priapism (erection lasting >4 hours): medical emergency requiring immediate treatment to prevent permanent penile damage [11][12]
- Cardiovascular events (MI, stroke, arrhythmia) in patients with pre-existing heart disease who exert themselves sexually [10][13]
- Sudden hearing loss (rare post-marketing reports) [9]
Safety & harm reduction
- Concomitant use of any organic nitrate (nitroglycerin, isosorbide, amyl nitrite/'poppers') — risk of fatal hypotension [7][8]
- Concomitant use of soluble guanylate cyclase stimulators (e.g. riociguat) [3]
- Severe hypotension at baseline (BP <90/50 mmHg) [10]
- Recent history of stroke, MI, or life-threatening arrhythmia [10]
- Coronary artery disease causing unstable angina [10]
- Previous episode of NAION [11]
- Severe hepatic impairment [10]
- Known hypersensitivity to sildenafil or excipients [7]
- PAH associated with sickle cell anaemia (Revatio indication) [7]
- Pulmonary veno-occlusive disease [7]
- Blood pressure before and during use, especially in patients on antihypertensive therapy [6]
- Cardiac status assessment before prescribing — patients for whom sexual activity is inadvisable should not use sildenafil [12]
- Vision: seek urgent care for any sudden visual change or loss [11]
- Erection duration: seek emergency care if erection lasts >4 hours [11]
- Organic nitrates (any form) — absolute contraindication, severe hypotension [7]
- Alpha-blockers (doxazosin etc.) — additive hypotension; separate doses by ≥4 hours [8]
- CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir, clarithromycin) — markedly raise sildenafil plasma levels; dose reduction or avoidance required [10]
- HIV protease inhibitors — limit sildenafil to 25 mg every 48 hours [5]
- Erythromycin, cimetidine — can prolong sildenafil half-life [5]
- Antihypertensive agents — additive vasodilation; monitor blood pressure [6]
- Grapefruit juice — may increase sildenafil plasma levels via CYP3A4 inhibition [14]
- Take 30–60 minutes before sexual activity; may be taken up to 4 hours before [4]
- High-fat meals delay absorption and can reduce peak concentrations — take in fasted or low-fat state for best onset [3]
- Start at the lowest effective dose (25 mg in higher-risk individuals) and titrate upward only if tolerated [10]
- Do not administer a nitrate for at least 24 hours after the last sildenafil dose [7]
- If used alongside alpha-blockers, maintain a separation interval of at least 4 hours [8]
Dosage context
For erectile dysfunction: commonly reported starting dose is 50 mg oral, taken approximately 1 hour before sexual activity; may be adjusted to 25 mg (tolerability) or 100 mg (inadequate response), taken no more than once per day [10]. For pulmonary arterial hypertension (Revatio®): the FDA-approved dose is 20 mg three times daily [4]. These are documented clinical doses, not prescriptive recommendations — always follow a prescribing clinician's guidance.
Sources
- 1.PubMed — Sildenafil pharmacology, PDE5 inhibition (IC50 3.5 nM)
- 2.ClinicalTrials.gov — Sildenafil mechanism, half-life (~4 h), endothelial effects
- 3.Pharmacology Mentor — PDE5 inhibitor class, mechanism, interactions
- 4.Wikipedia — PDE5 inhibitor class overview, contraindications
- 5.Wikipedia — Sildenafil: CYP interactions, alpha-blocker risk, protease inhibitors
- 6.PMC — PDE5 inhibitors: pharmacology and clinical applications (20-year review)
- 7.StatPearls / NIH — Sildenafil: indications, contraindications, nitrate interaction, NAION
- 8.Medicine.com — Sildenafil dosing, contraindications, alpha-blocker caution
- 9.ClinicalTrials.gov — Sildenafil adverse effects (PAH trial), half-life 4 h
- 10.Medscape — Sildenafil interactions (CYP3A4, alpha-blockers, antihypertensives)
- 11.FDA — Viagra (sildenafil) full prescribing label: NAION, priapism, nitrate contraindication
- 12.Healthline — Sildenafil (Viagra) side effects: priapism, NAION, blood pressure
- 13.BuzzRx — Sildenafil side effects: NAION, priapism, cardiovascular risk
- 14.Factually — PDE5 inhibitor short- and long-term side effects, drug interactions
- 15.PMC — Sildenafil arteriogenesis / collateral vessel growth research
This information is provided for educational and harm-reduction purposes only. It is not medical advice. These substances can carry serious health risks; effects and safe use vary by individual. Consult a qualified healthcare professional before use. Legal status varies by country — it is your responsibility to know your local law. We do not encourage misuse.
Other options for Sildenafil· 6 offers
Same compound from different labs/brands and pack sizes. Tap a row to switch brand — the price and buy button update instantly.
| Brand | Form | Strength | Pack | Price | Per mg |
|---|---|---|---|---|---|
CenforceSelected | blister-pack | 200 mg/tab | 10 tab | 21,90 € | €0.011/mg |
Cenforce | blister-pack | 200 mg/tab | 3 tab | 27,90 € | €0.047/mg |
Cenforce | blister-pack | 200 mg/tab | 20 tab | 31,90 € | €0.008/mg |
Cenforce | blister-pack | 200 mg/tab | 50 tab | 54,90 € | ★€0.005/mg |
Cenforce | blister-pack | 200 mg/tab | 10 tab | 84,90 € | €0.042/mg |
Cenforce | blister-pack | 200 mg/tab | 15 tab | 109,99 € | €0.037/mg |
Substance reviews(1)
Independent reviews of this compound from the wider market — about the substance, not our delivery.
- ★★★★★2 months ago
NDD, 10|10, SUPER FAST SHIPPING, RECOMMENDED