CAS number  YesY
ChemSpider  YesY
ATC code V04
Jmol-3D images Image 1
Molecular formula C5H9N3
Molar mass 111.15 g mol−1
ATC code

Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N   YesY/N?)

Betazole is a histamine H2 receptor agonist. Also known as Ametazole. Betazole hydrochloride is known as gastramine and histalog.

It has been used as a gastric stimulant to test for maximal production of gastric secretion activity [1] The test can be used in diagnosis of diseases such as Zollinger-Ellison syndrome where there is excess acid production, in this case driven by over production of gastrin. The volume of acid secretion is measured following administration of betazole, diagnosis being secretion greater than 60% of the maximal acid secretion following betazole stimulation. This procedure can lead to complications and should be avoided in subjects with coronary artery disease [2] It is also used in diagnosis of gastritis in association with a test for secretin activity

Betazole is used as a stimulant in preference to histamine because of its specificity for the H2 receptor and its advantage of not generating the undesirable side effects that histamine would induce. It therefore does not require concomitant use of antihistaminic compounds to block the actions of histamine at other histamine receptor types.

Its action in stimulating histamine release can be of use when testing the effectiveness of H2 receptor blocking drugs such as Nizatidine.[3]


  1. ^ Wruble LD Cummins AJ Goldenberg J Schapiro H (1967). "The effect of intravenous histalog on gastric secretion in man". Digestive Diseases and Sciences 12 (11): 1087–1090.  
  2. ^ Stoller JL Holubitsky IB Harrison RC Munro AI (1970). "Complications of the histalog test of gastric acid secretion". Digestive Diseases and Sciences 15 (7): 647–651.  
  3. ^ Hammond JB, Offen WW (1988). "Effect of nizatidine and cimetidine on betazole-stimulated gastric secretion of normal subjects: comparison of effects on acid, water, and pepsin.". Am J Gastroenterol. 83 (1): 32–6.