Small molecule
PubChem CID 135398744
Sildenafil
Viagra
- Mechanism of action
- Phosphodiesterase-5 (PDE5) inhibitor
- In plain language
- Relaxes blood vessels in specific tissues, boosting blood flow where the body's natural chemical signal for it is already active.
- How it works
- Sildenafil is a selective inhibitor of phosphodiesterase type 5 (PDE5), the enzyme responsible for degrading cyclic guanosine monophosphate (cGMP) in vascular smooth muscle. By inhibiting PDE5, sildenafil prolongs the local accumulation of cGMP generated in response to nitric oxide release during sexual stimulation, producing smooth muscle relaxation and increased arterial inflow into the corpus cavernosum. This effect is dependent on sexual stimulation to trigger nitric oxide release. The same PDE5-inhibition mechanism, applied to pulmonary vascular smooth muscle, underlies its use in pulmonary arterial hypertension.
- Therapeutic applications
- As Viagra, indicated for the treatment of erectile dysfunction in men. The same active ingredient, marketed as Revatio, is indicated to reduce pulmonary vascular resistance in pulmonary arterial hypertension; the two products should not be co-administered.
- Class
- Small molecule
- Therapeutic area
- Vascular
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