Sildenafil works by inhibiting a specific enzyme called phosphodiesterase-5 (PDE5). This enzyme breaks down cyclic guanosine monophosphate (cGMP), a molecule crucial for achieving and maintaining an erection.
By blocking PDE5, sildenafil allows cGMP levels to rise. Increased cGMP relaxes the smooth muscles in the blood vessels of the penis, leading to increased blood flow.
The Role of Nitric Oxide
This process is initiated by nitric oxide (NO), a neurotransmitter released during sexual stimulation. NO triggers the production of cGMP, setting the stage for sildenafil’s action. Sildenafil enhances the effects of NO, making the process more efficient.
Simplified Summary
| 1. Sexual Stimulation | Releases nitric oxide (NO). |
| 2. NO Action | Increases cyclic GMP (cGMP) levels. |
| 3. Sildenafil’s Role | Inhibits PDE5, preventing cGMP breakdown. |
| 4. Result | Increased blood flow to the penis, facilitating an erection. |
Important Note:
Sildenafil requires sexual stimulation to be effective. It doesn’t directly cause an erection; it facilitates the physiological response to sexual stimulation.
