Fildena 100 mg, containing sildenafil citrate, is a medication used to treat erectile dysfunction (ED) in men. Understanding its mechanism of action involves looking at how sildenafil citrate interacts with the body to facilitate erections. Here’s a detailed explanation of how Fildena 100 mg works:

1. Phosphodiesterase Type 5 (PDE5) Inhibition

• Role of PDE5: PDE5 is an enzyme found in various tissues in the body, including the corpus cavernosum of the penis. Its primary function is to break down cyclic guanosine monophosphate (cGMP), a molecule that regulates blood flow.
• Inhibition by Sildenafil: Sildenafil citrate, the active ingredient in Fildena 100 mg, inhibits the action of PDE5. By blocking PDE5, sildenafil prevents the degradation of cGMP, leading to increased levels of cGMP in the penile tissues.

2. Increased Levels of cGMP

• cGMP Production: Sexual stimulation triggers the release of nitric oxide (NO) in the corpus cavernosum. NO activates the enzyme guanylate cyclase, which increases the levels of cGMP.
• Role of cGMP: Elevated cGMP levels cause the smooth muscle cells in the walls of the blood vessels supplying the penis to relax. This relaxation results in the dilation of blood vessels, allowing increased blood flow into the corpus cavernosum.

3. Relaxation of Smooth Muscle and Vasodilation

• Smooth Muscle Relaxation: The increased concentration of cGMP leads to the relaxation of smooth muscles in the penile arteries and the trabecular smooth muscle.
• Enhanced Blood Flow: As the smooth muscles relax, blood vessels dilate, and the blood flow to the penile tissues increases. This enhanced blood flow is essential for the engorgement and expansion of the corpus cavernosum, which results in an erection.

4. Erection Formation

• Blood Trapping: The influx of blood fills the corpus cavernosum, causing the penis to become rigid and erect. The veins that normally drain blood from the penis are compressed, preventing the outflow of blood and maintaining the erection.
• Sexual Stimulation Requirement: It’s important to note that Fildena 100 mg requires sexual stimulation to be effective. The presence of sexual arousal is necessary to initiate the release of NO and the subsequent production of cGMP.

5. Duration of Effect

• Effective Window: The effects of Fildena 100 mg typically begin within 30 to 60 minutes after ingestion and can last for up to 4 to 6 hours. During this period, men can achieve and maintain an erection sufficient for sexual activity when sexually stimulated.

6. Metabolism and Excretion

• Liver Metabolism: Sildenafil citrate is metabolized primarily by the liver enzymes CYP3A4 (major route) and CYP2C9 (minor route).
• Excretion: The metabolites of sildenafil are excreted predominantly in the feces (approximately 80%) and to a lesser extent in the urine (approximately 13%).

Conclusion

The mechanism of action of Fildena 100 mg centers around its ability to inhibit the PDE5 enzyme, leading to increased levels of cGMP in the penile tissues. This results in the relaxation of smooth muscles and enhanced blood flow to the penis, facilitating the formation of an erection during sexual stimulation. By understanding this process, users can appreciate how Fildena 150 mg effectively treats erectile dysfunction and helps improve sexual performance.