title: Effects of cimetidine and ranitidine on basal gastric pH, free and total acid contents in horses.
abstract: The basal gastric pH, free and total acid contents from five adult horses were determined at two-hour intervals for six- to eight-hour periods. The basal gastric pH, free and total acid contents varied from 2.14 +/- 0.08 to 2.41 +/- 0.14, 28.63 +/- 8.27 to 17.89 +/- 2.86 mmol litre-1 and 41.38 +/- 9.72 to 37.38 +/- 3.70 mmol litre-1, respectively. Cimetidine (8.8 mg kg-1 orally) and ranitidine (2.2 mg kg-1 orally) increased the basal gastric pH to above 3.6 (P less than 0.05) with a concomitant reduction of 75 per cent and 75 to 100 per cent in the basal gastric free acid content, respectively, for an eight-hour period. Cimetidine (4.4 mg kg-1, intramuscularly) and ranitidine (1.4 mg kg-1, intramuscularly) increased the basal gastric pH to above 3.6 with a concomitant reduction of 54 to 93 per cent and 69 to 100 per cent in the basal gastric free acid content, respectively, for an eight-hour period. This study shows that the horse is a basal acid secretor, and that cimetidine and ranitidine, two widely used histaminergic-H2 type antagonists in human clinical practice are effective in horses with ranitidine being approximately four times more potent than cimetidine.
authors.affiliation: Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078.
authors.forename: S
authors.initials: S
authors.lastname: Sangiah
authors.forename: C C
authors.initials: CC
authors.lastname: McAllister
authors.forename: H R
authors.initials: HR
authors.lastname: Amouzadeh
mesh_terms: D000818:Animals; D002927:Cimetidine / Q000494:pharmacology*; D005744:Gastric Acid / Q000378:metabolism*; D005745:Gastric Acidity Determination / Q000662:veterinary; D006736:Horses / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D011899:Ranitidine / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D002927:Cimetidine; D011899:Ranitidine