Comparative Pharmacology
Head-to-head clinical analysis: SILDENAFIL CITRATE versus VIAGRA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SILDENAFIL CITRATE versus VIAGRA.
SILDENAFIL CITRATE vs VIAGRA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Sildenafil citrate inhibits phosphodiesterase type 5 (PDE5) in the corpus cavernosum, increasing cGMP levels and enhancing nitric oxide-mediated smooth muscle relaxation, leading to penile erection. It also inhibits PDE5 in pulmonary vasculature, causing vasodilation and reducing pulmonary artery pressure.
Sildenafil inhibits phosphodiesterase type 5 (PDE5), increasing cGMP levels in corpus cavernosum, leading to smooth muscle relaxation and blood flow into the penis.
50 mg orally as needed approximately 1 hour before sexual activity; range 25-100 mg based on efficacy and tolerability; maximum dosing frequency once per day.
50 mg orally once as needed approximately 1 hour before sexual activity; range 25-100 mg based on efficacy and tolerability. Maximum dosing frequency: once per day.
None Documented
None Documented
Terminal elimination half-life 3-5 hours; clinical effect duration shorter due to distribution.
Terminal elimination half-life approximately 4 hours (range 3–5 hours). No significant accumulation with recommended dosing.
Approximately 80% fecal, 13% renal as metabolites; <1% unchanged in urine.
Renal (approximately 80% as metabolites, 20% as unchanged drug in feces), biliary/fecal (about 13% unchanged in feces). Total clearance 41 L/h.
Category A/B
Category C
PDE5 Inhibitor
PDE5 Inhibitor