Viagra

Sildenafil
Clinical data


Pronunciation	sil-DEN-ə-fil
Trade names	Viagra, Revatio, others
AHFS/Drugs.com	Monograph
MedlinePlus	a699015
License data	EU EMA: Viagra US FDA: Sildenafil
Pregnancy category	AU: B1 US: B (No risk in non-human studies)
Routes of administration	By mouth (tablets), IV
ATC code	G04BE03 (WHO)
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
IUPAC name 5-{2-Ethoxy-5-[(4-methylpiperazin-1-yl)sulfonyl]phenyl}-1-methyl-3-propyl-1H,6H,7H-pyrazolo[4,3-d]pyrimidin-7-one
CAS Number	139755-83-2^Y Citrate: 171599-83-0^N
PubChem CID	5212
DrugBank	DB00203^Y
ChemSpider	5023^N
UNII	3M7OB98Y7H
KEGG	D08514^Y
ChEBI	CHEBI:9139^N
ChEMBL	CHEMBL192^Y
PDB ligand	VIA (PDBe, RCSB PDB)
ECHA InfoCard	100.122.676
Chemical and physical data
Formula	C₂₂H₃₀N₆O₄S
Molar mass	474.5764 g/mol
3D model (Jmol)	Interactive image
SMILES CCCC1=NN(C2=C1NC(=NC2=O)C3=C(C=CC(=C3)S(=O)(=O)N4CCN(CC4)C)OCC)C
InChI InChI=1S/C22H30N6O4S/c1-5-7-17-19-20(27(4)25-17)22(29)24-21(23-19)16-14-15(8-9-18(16)32-6-2)33(30,31)28-12-10-26(3)11-13-28/h8-9,14H,5-7,10-13H2,1-4H3,(H,23,24,29)^N Key:BNRNXUUZRGQAQC-UHFFFAOYSA-N^N
^NY (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