Effect of aluminum hydroxide/magnesium hydroxide antacid and bismuth subsalicylate on gastric pH in horses.
OBJECTIVE
To assess the effect of aluminum hydroxide/magnesium hydroxide antacid and bismuth subsalicylate on gastric pH in clinically normal horses and to develop guidelines on the use of these agents for treatment of peptic ulcer disease in horses.


METHODS
Prospective, randomized, controlled trial.


METHODS
5 clinically normal adult horses with chronically implanted gastric cannulas.


METHODS
Each horse received all 5 treatments (30 g of aluminum hydroxide/15 g of magnesium hydroxide, 12 g of aluminum hydroxide/6 g of magnesium hydroxide, 10.5 g of bismuth subsalicylate, 26.25 g of bismuth subsalicylate, and 5% methylcellulose control) with only 1 experiment performed each day. Gastric pH was measured via a glass electrode inserted through the gastric cannula for 1 hour before treatment and continued for 2 hours after treatment. Food or water was not given to the horses during the experiment. Measurements of gastric pH obtained during posttreatment hours were compared with pretreatment gastric pH values.


RESULTS
Only a dose of 30 g of aluminum hydroxide/ 15 g of magnesium hydroxide resulted in a significant increase in gastric pH over baseline or control values. Mean pH was 5.2 +/- 0.62 and 4.59 +/- 0.48 for posttreatment hours 1 and 2, respectively.


CONCLUSIONS
Oral administration of 30 g of aluminum hydroxide/15 g of magnesium hydroxide to adult horses should result in a mean hourly gastric pH > or = 4.0 for at least 2 hours.
Clark
C K
CK
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610-0136, USA.
Merritt
A M
AM
Burrow
J A
JA
Steible
C K
CK
D000284:Administration, Oral; D000536:Aluminum Hydroxide / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D000863:Antacids / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D001729:Bismuth / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D005260:Female; D005745:Gastric Acidity Determination / Q000662:veterinary; D005753:Gastric Mucosa / Q000378:metabolism; D006734:Horse Diseases / Q000188:drug therapy; D006736:Horses / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008276:Magnesium Hydroxide / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D010437:Peptic Ulcer / Q000188:drug therapy / Q000662:veterinary; D011446:Prospective Studies; D012459:Salicylates / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D013270:Stomach / Q000187:drug effects*
D000863:Antacids; D009942:Organometallic Compounds; D012459:Salicylates; D000536:Aluminum Hydroxide; C015715:bismuth subsalicylate; D008276:Magnesium Hydroxide; D001729:Bismuth