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Viagra

Sildenafil
Sildenafil structure.svg
Sildenafil-from-xtal-3D-balls.png
Clinical data
Pronunciation sil-DEN-ə-fil
Trade names Viagra, Revatio, others
AHFS/Drugs.com Monograph
MedlinePlus a699015
License data
Pregnancy
category
  • AU: B1
  • US: B (No risk in non-human studies)
Routes of
administration
By mouth (tablets), IV
ATC code
Legal status
Legal status
  • AU: S4 (Prescription only)
  • CA: ℞-only
  • UK: POM (Prescription only)
  • US: ℞-only
  • In general: ℞ (Prescription only)
Pharmacokinetic data
Bioavailability 41% (mean)
Protein binding ~96%
Metabolism Liver: CYP3A4 (major route), CYP2C9 (minor route)
Metabolites N-desmethylsildenafil (~50% potency for PDE5)
Biological half-life 3–4 hours
Excretion Feces (~80%), urine (~13%)
Identifiers
CAS Number
PubChem CID
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
PDB ligand
ECHA InfoCard 100.122.676
Chemical and physical data
Formula C22H30N6O4S
Molar mass 474.5764 g/mol
3D model (Jmol)
 NYesY (what is this?)  

Sildenafil, sold as the brand name Viagra among others, is a medication used to treat erectile dysfunction and pulmonary arterial hypertension. Its effectiveness for treating sexual dysfunction in women has not been demonstrated.

Common side effects include headaches and heartburn, as well as flushed skin. Caution is advised in those who have cardiovascular disease. Rare but serious side effects include prolonged erections, which can lead to damage to the penis, and sudden-onset hearing loss. Sildenafil should not be taken by people who take nitrates such as nitroglycerin (glycerin trinitrate), as this may result in a severe and potentially fatal drop in blood pressure.

Sildenafil acts by inhibiting cGMP-specific phosphodiesterase type 5 (phosphodiesterase 5, PDE5), an enzyme that promotes degradation of cGMP, which regulates blood flow in the penis.

Pfizer scientists Andrew Bell, David Brown, and Nicholas Terrett originally discovered sildenafil as a treatment for various cardiovascular disorders. Since becoming available in 1998, sildenafil has been a common treatment for erectile dysfunction; its primary competitors are tadalafil (trade name Cialis) and vardenafil (Levitra).

The primary indication of sildenafil is treatment of erectile dysfunction (inability to sustain a satisfactory erection to complete intercourse). Its use is now one of the standard treatment for erectile dysfunction, including for men with diabetes mellitus.


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Wikipedia

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