My Cart

0 Item(s): $0.00

You have no items in your shopping cart.

Sildenafil Mechanism

Sildenafil Mechanism


sildenafil mechanism is a vasoactive agent used to treat erectile dysfunction and reduce symptoms in patients with pulmonary arterial hypertension (PAH). Sildenafil elevates levels of the second messenger, cGMP, by inhibiting its breakdown via phosphodiesterase type 5 (PDE5). PDE5 is found in particularly high concentrations in the corpus cavernosum, erectile tissue of the penis. It is also found in the retina and vascular endothelium. Increased cGMP results in vasodilation which facilitates generation and maintenance of an erection. The vasodilatory effects of sildenafil also help reduce symptoms of PAH.

The molecular mechanisms of the effects of sildenafil, a specific inhibitor of cyclic guanosine monophosphate (cGMP) phosphodiesterases are briefly reviewed. The second messenger cGMP as well as its molecular targets (with the exception of the photoreceptor signal transduction machinery) have long played an underdog role compared with cyclic adenosine monophosphate and other signalling molecules such as inositoltrisphosphate.

how does it work (mechanism of action)?

sildenafil mechanism is an oral drug that is used for treating impotence. It is in a class of drugs called phosphodiesterase inhibitors (PDE-5 inhibitors) that also includes.

Mechanism Of Action

The sildenafil mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. Sildenafil enhances the effect of NO by inhibiting phosphodiesterase type 5 (PDE5), which is responsible for degradation of cGMP in the corpus cavernosum.

What is the dosage for sildenafil?

The usual recommended dose is 25 to 100 mg 1 hour before sexual activity. The maximum dose is 100 mg daily.The elderly (over 65 years of age) should start at 25 mg before sexual activity.

sildenafil mechanism is rapidly absorbed. Maximum observed plasma concentrations are reached within 30 to 120 minutes (median 60 minutes) of oral dosing in the fasted state. When sildenafil mechanism is taken with a high fat meal, the rate of absorption is reduced, with an average delay in the time to maximal concentration of 1 hour.

Effects and mechanism of action of sildenafil

All studies, conducted in four separate series of experiments, followed a randomized, controlled, paired design. In each experiment, 4 chorionic rings, each 3 mm in length, from a single chorionic plate artery were isolated, mounted in physiologic saline solution at 37°C, and equilibrated with 95% O2 – 5% CO2 in tissue baths (10 ml capacity) as previously described [16, 17] (Figure 1). Samples of the solution were intermittently analyzed for PO2, PCO2 and pH, using an automated blood-gas analyzer (ABL500, Radiometer Copenhagen, Denmark).

sildenafil mechanism side effect

  • Cardiovascular
  • Prolonged Erection and Priapism
  • Effects on the Eye
  • Hearing Loss
  • Hypotension when Co-administered with Alpha-blockers or Anti-hypertensives
  • Adverse Reactions with the Concomitant Use of Ritonavir
  • Combination with other PDE5 Inhibitors or Other Erectile Dysfunction Therapies
  • Effects on Bleeding


Phosphodiesterase-5 is present in the feto-placental circulation. Sildenafil citrate vasodilates the feto-placental circulation via a cGMP dependent mechanism involving increased responsiveness to NO.