Famotidine

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Famotidine
Famotidine.svg
Famotidine-from-xtal-polymorph-A-3D-balls.png
Systematic (IUPAC) name
3-([2-(diaminomethyleneamino)thiazol- 4-yl]methylthio)- N'-sulfamoylpropanimidamide
Clinical data
Trade namesPepcid
AHFS/Drugs.commonograph
MedlinePlusa687011
Licence dataUS FDA:link
Pregnancy cat.B1 (Au), B (U.S.)
Legal statusPharmacist only S3/S4(AU), General Availability (OTC)(UK),
Over the Counter(US)
RoutesOral (tablet form)
Pharmacokinetic data
Bioavailability40-45% (Oral)[1]
Protein binding15-20%[1]
Metabolismhepatic
Half-life2.5-3.5 hours[1]
ExcretionRenal (25-30% unchanged [Oral])[1]
Identifiers
CAS number76824-35-6 YesY
ATC codeA02BA03
PubChemCID 3325
DrugBankDB00927
ChemSpider3208 YesY
UNII5QZO15J2Z8 YesY
KEGGD00318 YesY
ChEBICHEBI:4975 YesY
ChEMBLCHEMBL902 YesY
Chemical data
FormulaC8H15N7O2S3 
Mol. mass337.449 g/mol
 YesY (what is this?)  (verify)
 
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Famotidine
Famotidine.svg
Famotidine-from-xtal-polymorph-A-3D-balls.png
Systematic (IUPAC) name
3-([2-(diaminomethyleneamino)thiazol- 4-yl]methylthio)- N'-sulfamoylpropanimidamide
Clinical data
Trade namesPepcid
AHFS/Drugs.commonograph
MedlinePlusa687011
Licence dataUS FDA:link
Pregnancy cat.B1 (Au), B (U.S.)
Legal statusPharmacist only S3/S4(AU), General Availability (OTC)(UK),
Over the Counter(US)
RoutesOral (tablet form)
Pharmacokinetic data
Bioavailability40-45% (Oral)[1]
Protein binding15-20%[1]
Metabolismhepatic
Half-life2.5-3.5 hours[1]
ExcretionRenal (25-30% unchanged [Oral])[1]
Identifiers
CAS number76824-35-6 YesY
ATC codeA02BA03
PubChemCID 3325
DrugBankDB00927
ChemSpider3208 YesY
UNII5QZO15J2Z8 YesY
KEGGD00318 YesY
ChEBICHEBI:4975 YesY
ChEMBLCHEMBL902 YesY
Chemical data
FormulaC8H15N7O2S3 
Mol. mass337.449 g/mol
 YesY (what is this?)  (verify)

Famotidine (INN) /fəˈmɒtɪdn/ is a histamine H2-receptor antagonist that inhibits stomach acid production, and it is commonly used in the treatment of peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD/GORD). It is commonly marketed by Johnson & Johnson/Merck under the trade names Pepcidine and Pepcid and by Astellas under the trade name Gaster. Unlike cimetidine, the first H2 antagonist, famotidine has no effect on the cytochrome P450 enzyme system, and does not appear to interact with other drugs.[2]

Medical use[edit]

Certain preparations of famotidine are available over the counter (OTC) in various countries. In the US 20 or more mg, sometimes in combination with a more traditional antacid, are available OTC. Larger doses still require a prescription.[citation needed]

Famotidine is given to surgery patients before operations to prevent postoperative nausea and to reduce the risk of aspiration pneumonitis. Famotidine is also given to some patients taking NSAIDs, to prevent peptic ulcers.[3] It serves as an alternative to proton-pump inhibitors.[4]

It is also given to dogs with acid reflux.

Famotidine has also been used in combination with an H1 antagonist to treat and prevent urticaria caused by an acute allergic reaction.[5]

Side-effects[edit]

Side-effects are associated with famotidine use. In clinical trials, the most common adverse effects were headache, dizziness, and constipation or diarrhea.[6] Antacid preparations such as famotidine, by suppressing acid-mediated breakdown of proteins, lead to an elevated risk of developing food or drug allergies. This happens due to undigested proteins then passing into the gastrointestinal tract where sensitization occurs. It is unclear whether this risk occurs with only long-term use or with short-term use as well.[7]

History[edit]

Famotidine was developed by Yamanouchi Pharmaceutical Co.[8] It was licensed in the mid-80s by Merck & Co.[9] 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 30 times more active than cimetidine.[citation needed]

It was first marketed in 1981. Pepcid RPD orally-disintegrating tablets were released in 1999. Generic preparations became available in 2001, e.g.Fluxid (Schwarz) or Quamatel (Gedeon Richter Ltd.).

In the United States and Canada, a product called Pepcid Complete, which combines famotidine with an antacid in a chewable tablet to quickly relieve the symptoms of excess stomach acid, is available. In the UK, this product is known as Pepcidtwo.

Famotidine suffers from poor bioavailability (50%), as it is poorly soluble in the low pH of the stomach. Famotidine used in combination with antacids promotes local delivery of these drugs to the receptor of the parietal cell wall. Therefore, researchers are developing innovative formulations of tablets, such as gastroretentive drug delivery systems. Such tablets are retained in the stomach for a longer period of time, thereby improving the bioavailability of drugs. Local delivery also increases bioavailability at the stomach wall receptor site and increases the efficacy of drugs to reduce acid secretion.[10]

Research[edit]

Famotidine has been investigated as an adjunct in treatment-resistant schizophrenia. In one trial it caused a 10% reduction in schizophrenic symptom severity in treatment-resistant patients.[11]

See also[edit]

References[edit]

  1. ^ a b c d Truven Health Analytics, Inc. DRUGDEX® System (Internet) [cited 2013 Oct 10]. Greenwood Village, CO: Thomsen Healthcare; 2013.
  2. ^ Humphries TJ, Merritt GJ (August 1999). "Review article: drug interactions with agents used to treat acid-related diseases" (pdf). Aliment. Pharmacol. Ther. 13 (Suppl 3): 18–26. doi:10.1046/j.1365-2036.1999.00021.x. PMID 10491725. 
  3. ^ "Horizon Pharma, Inc. Announces FDA Approval of DUEXIS(R) for the Relief of the Signs and Symptoms of Rheumatoid Arthritis and Osteoarthritis and to Decrease the Risk of Developing Upper Gastrointestinal Ulcers" (Press release). Horizon Pharma. 2011-04-25. 
  4. ^ Brauser D (Jul 13, 2009). "Famotidine May Prevent Peptic Ulcers, Esophagitis in Patients Taking Low-Dose Aspirin". Medscape. 
  5. ^ Fogg TB, Semple D (29 November 2007). "Combination therapy with H2 and H1 antihistamines in acute, non compromising allergic reactions". BestBets. Manchester, England: Manchester Royal Infirmary. Retrieved 26 April 2011. 
  6. ^ "Pepcid Side Effects & Drug Interactions". RxList.com. 2008. Retrieved 2008-07-31. 
  7. ^ Pali-Schöll I, Jensen-Jarolim E (April 2011). "Anti-acid medication as a risk factor for food allergy". Allergy 66 (4): 469–477. doi:10.1111/j.1398-9995.2010.02511.x. PMID 21121928. 
  8. ^ US patent 4283408, HIRATA YASUFUMI; YANAGISAWA ISAO; ISHII YOSHIO; TSUKAMOTO SHINICHI; ITO NORIKI; ISOMURA YASUO; TAKEDA MASAAKI, "Guanidinothiazole compounds, process for preparation and gastric inhibiting compositions containing them", issued 1981-08-11 
  9. ^ "Sankyo Pharma". Skyscape Mediwire. 2002. Retrieved 2009-10-30. [dead link]
  10. ^ "Formulation and Evaluation of Gastroretentive Floating Tablets of Famotidine". Farmavita.Net. 2008. Retrieved 2009-01-30. 
  11. ^ Meskanen, K; Ekelund, H; Laitinen, J; Neuvonen, PJ; Haukka, J; Panula, P; Ekelund, J (August 2013). "A randomized clinical trial of histamine 2 receptor antagonism in treatment-resistant schizophrenia.". Journal of Clinical Psychopharmacology 33 (4): 472–478. doi:10.1097/JCP.0b013e3182970490. PMID 23764683.