Famotidine

Famotidine
Clinical data


Pronunciation	/fəˈmɒtɪdiːn/
Trade names	Pepcid, others
AHFS/Drugs.com	Monograph
MedlinePlus	a687011
License data	US FDA: Famotidine
Pregnancy category	AU: B1 US: B (No risk in non-human studies)
Routes of administration	Oral (tablets), Intravenous
ATC code	A02BA03 (WHO)
Legal status
Legal status	AU: S3 (Pharmacist only) /S4; pharmacist only UK: General sales list (GSL, OTC) US: OTC
Pharmacokinetic data
Bioavailability	40–45% (oral)
Protein binding	15–20%
Metabolism	hepatic
Biological half-life	2.5–3.5 hours
Excretion	Renal (25-30% unchanged [Oral])
Identifiers
IUPAC name 3-[({2-[(diaminomethylidene)amino]-1,3-thiazol-4-yl}methyl)sulfanyl]-N'-sulfamoylpropanimidamide
CAS Number	76824-35-6^Y
PubChem CID	3325
IUPHAR/BPS	7074
DrugBank	DB00927^Y
ChemSpider	3208^Y
UNII	5QZO15J2Z8
KEGG	D00318^Y
ChEBI	CHEBI:4975^Y
ChEMBL	CHEMBL902^Y
ECHA InfoCard	100.116.793
Chemical and physical data
Formula	C₈H₁₅N₇O₂S₃
Molar mass	337.449 g/mol
3D model (Jmol)	Interactive image
SMILES NS(=O)(=O)/N=C(\N)CCSCc1csc(n1)N=C(N)N
InChI InChI=1S/C8H15N7O2S3/c9-6(15-20(12,16)17)1-2-18-3-5-4-19-8(13-5)14-7(10)11/h4H,1-3H2,(H2,9,15)(H2,12,16,17)(H4,10,11,13,14)^Y Key:XUFQPHANEAPEMJ-UHFFFAOYSA-N^Y

Famotidine, sold under the trade name Pepcid among others, is a histamine H₂ receptor antagonist that inhibits stomach acid production. It is commonly used in the treatment of peptic ulcer disease and gastroesophageal reflux disease.

Unlike cimetidine, the first H₂ antagonist, famotidine has no effect on the enzyme system, and does not appear to interact with other drugs.

It was discovered in 1979.

Famotidine is also given to dogs and cats with acid reflux. Famotidine has been used in combination with an H₁ antagonist to treat and prevent urticaria caused by an acute allergic reaction.

Certain preparations of famotidine are available over the counter (OTC) in various countries. In the United States and Canada, 10 mg and 20 mg tablets, sometimes in combination with an antacid, are available OTC. Larger doses still require a medical prescription.

Formulations of famotidine in combination with ibuprofen were marketed by Horizon Pharma under the trade name Duexis.

Side effects associated with famotidine use include headache, dizziness, and constipation or diarrhea.

Famotidine was developed by Yamanouchi Pharmaceutical Co. It was licensed in the mid-1980s by Merck & Co. and is marketed by a joint venture between Merck and Johnson & Johnson. The imidazole ring of cimetidine was replaced with a 2-guanidinothiazole ring. Famotidine proved to be 9 times more potent than ranitidine, and 32 times more potent than cimetidine.

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Wikipedia