Gastroenterology Book

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H2 Receptor AntagonistAka: H2 Antagonist, Famotidine, Pepcid, H2 Blocker, Ranitidine, Zantac, Cimetidine, Tagamet, Nizatidine, Axid

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  1. Mechanism
    1. Inhibits histamine action at parietal cell H2 receptor
    2. Decreases basal and food stimulated acid secretion
    3. Inhibits 50-80% of daily gastric acid secretion
  2. Preparations
    1. Ranitidine (Zantac)
      1. Bolus IV Dosing: 50 mg IV q6-8h
      2. Continuous IV Dosing: 6.25 mg/h IV
      3. Oral Dosing: 150 mg PO bid
    2. Cimetidine (Tagamet)
      1. Bolus parenteral dosing: 300 mg IV or IM q6h
      2. Continuous IV Dosing: 37.5 mg/h IV
      3. Oral Dosing: 400 mg PO bid
    3. Famotidine (Pepcid)
      1. Oral dosing: 20 to 40 mg PO bid
    4. Nizatidine (Axid)
      1. Oral dosing: 150 mg PO bid
  3. Efficacy
    1. Similar efficacy among all 4 agents
    2. H2 Blockers are not as effective in Tobacco abuse
      1. Carafate and Prilosec preferred in this population
    3. Symptomatic relief of GERD in weeks in 70% of cases
      1. Devault (1999) Am J Gastroenterol 94:1434
  4. Disadvantages
    1. Even generic costs still approch Proton Pump Inhibitors
      1. (2003) Red Book, Medical Economics Data, Montvale, NJ
  5. Adverse Effects
    1. Cimetidine has more drug interactions and side effects

Cimetidine (C0008783)

Definition (MSH)A histamine congener, it competitively inhibits HISTAMINE binding to HISTAMINE H2 RECEPTORS. Cimetidine has a range of pharmacological actions. It inhibits GASTRIC ACID secretion, as well as PEPSIN and GASTRINS output. It also blocks the activity of CYTOCHROME P-450 which might explain proposals for use in NEOADJUVANT THERAPY.
Definition (CSP)histamine congener; competitively inhibits histamine binding to H2 receptors, inhibits gastric acid secretion, pepsin, and gastrin output, and blocks the activity of cytochrome P-450.
Definition (NCI)A drug usually used to treat stomach ulcers and heartburn. It is also commonly used in a regimen to prevent allergic reactions.
Definition (PDQ)A histamine H(2)-receptor antagonist. Enhancing anti-tumor cell-mediated responses, cimetidine blocks histamine's ability to stimulate suppressor T lymphocyte activity and to inhibit natural killer (NK) cell activity and interleukin-2 production. Cimetidine also may inhibit tumor growth by suppressing histamine's growth-factor activity and blocking histamine-induced stimulation of vascular endothelial growth factor (VEGF), a pro-angiogenic growth factor. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=39185&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=39185&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C374" NCI Thesaurus)
Definition (NCI)A histamine H(2)-receptor antagonist. Enhancing anti-tumor cell-mediated responses, cimetidine blocks histamine's ability to stimulate suppressor T lymphocyte activity and to inhibit natural killer (NK) cell activity and interleukin-2 production. Cimetidine also may inhibit tumor growth by suppressing histamine's growth-factor activity and blocking histamine-induced stimulation of vascular endothelial growth factor (VEGF), a pro-angiogenic growth factor. (NCI04)
ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
MSHD002927
EnglishCimetidine, CIMETIDINE PREPARATION
Spanishcimetidina
Parent ConceptsHeterocyclic Compounds, 1-Ring (C0019399), Anti-Ulcer Agents (C0003216), Guanidines (C0018320), Imidazoles (C0020924), Chemo Immunostimulant Adjuvant (C1516461), Endothelial Cell Inhibitor (C1516868), Histamine Antagonists (C0019590), Histamine H2 Antagonists (C0019593)
SourcesAOD, CSP, LCH, LNC, MSH, MTHSPL, NCI, NDFRT, PDQ, RXNORM, SCTSPA, SNOMEDCT, USPMG, VANDF
Derived from the NIH UMLS (Unified Medical Language System)


Famotidine (C0015620)

Definition (MSH)A competitive histamine H2-receptor antagonist. Its main pharmacodynamic effect is the inhibition of gastric secretion.
Definition (NCI)A propanimidamide and histamine H2-receptor antagonist with antacid activity. Famotidine is a competitive inhibitor of histamine H2-receptors located on the basolateral membrane of the parietal cell, thereby reducing basal and nocturnal gastric acid secretion, resulting in a reduction in gastric volume, acidity, and amount of gastric acid released in response to stimuli.
ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
MSHD015738
EnglishFamotidine, FAMOTIDINE PREPARATION
Spanishfamotidina
Parent ConceptsThiazoles (C0039859), Histamine H2 Antagonists (C0019593), Histamine Antagonists (C0019590), [GA303] H.PYLORI AGENTS (C0973551)
SourcesAOD, LNC, MSH, MTHSPL, NCI, NDFRT, RXNORM, SCTSPA, SNOMEDCT, USPMG, VANDF
Derived from the NIH UMLS (Unified Medical Language System)


Ranitidine (C0034665)

Definition (MSH)A non-imidazole blocker of those histamine receptors that mediate gastric secretion (H2 receptors). It is used to treat gastrointestinal ulcers.
Definition (CSP)N-2-(5-dimethylamino)methyl-2- furanylmethyl thioethyl-N'-methyl-2-nitro-1,1 -ethenediamine; cimetidine analog; H2 histamine receptor antagonist used to treat gastric ulcers.
Definition (NCI)A member of the class of histamine H2-receptor antagonists with antacid activity. Ranitidine is a competitive and reversible inhibitor of the action of histamine, released by enterochromaffin-like (ECL) cells, at the histamine H2-receptors on parietal cells in the stomach, thereby inhibiting the normal and meal-stimulated secretion of stomach acid. In addition, other substances that promote acid secretion have a reduced effect on parietal cells when the H2 receptors are blocked.
ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
MSHD011899
EnglishRanitidin, Ranitidine, RANITIDINE PREPARATION
Spanishranitidina
Parent Conceptsfuran (C0060850), Anti-Ulcer Agents (C0003216), Furans (C0016850), Histamine H2 Antagonists (C0019593), Histamine Antagonists (C0019590), [GA303] H.PYLORI AGENTS (C0973551)
SourcesAOD, CSP, LCH, LNC, MSH, MTHSPL, NCI, NDFRT, RXNORM, SCTSPA, SNOMEDCT, USPMG, VANDF
Derived from the NIH UMLS (Unified Medical Language System)


Nizatidine (C0085154)

Definition (MSH)A histamine H2 receptor antagonist with low toxicity that inhibits gastric acid secretion. The drug is used for the treatment of duodenal ulcers.
Definition (NCI)A competitive and reversible histamine H2-receptor antagonist with antacid activity. Nizatidine inhibits the histamine H2-receptors located on the basolateral membrane of the gastric parietal cell, thereby reducing basal and nocturnal gastric acid secretion, resulting in a reduction in gastric volume, acidity, and amount of gastric acid released in response to stimuli.
ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
MSHD016567
EnglishNizatidine, NIZATIDINE PREPARATION
Spanishnizatidina
Parent ConceptsThiazoles (C0039859), Histamine H2 Antagonists (C0019593), Histamine Antagonists (C0019590), [GA303] H.PYLORI AGENTS (C0973551)
SourcesLNC, MSH, MTHSPL, NCI, NDFRT, RXNORM, SCTSPA, SNOMEDCT, USPMG, VANDF
Derived from the NIH UMLS (Unified Medical Language System)


Tagamet (C0592157)

ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
MSHD002927
EnglishTagamet
SourcesCSP, MSH, NCI, PDQ, RXNORM
Derived from the NIH UMLS (Unified Medical Language System)


Zantac (C0592278)

ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
MSHD011899
EnglishZantac
SourcesMSH, NCI, RXNORM
Derived from the NIH UMLS (Unified Medical Language System)


Pepcid (C0678119)

ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
MSHD015738
EnglishPepcid
SourcesMSH, NCI, RXNORM
Derived from the NIH UMLS (Unified Medical Language System)


Axid (C0678129)

ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
MSHD016567
EnglishAxid
SourcesMSH, NCI, RXNORM
Derived from the NIH UMLS (Unified Medical Language System)



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