Effect of acepromazine, diazepam, fentanyl-droperidol, and oxymorphone on gastroesophageal sphincter pressure in healthy dogs.

Treatment of healthy dogs with 4 commonly used psychotropic or analgesic agents significantly decreased resting gastroesophageal sphincter pressure (GESP). Acepromazine decreased GESP by 35% (P = 0.02); oxymorphone decreased GESP by 38% (P less than 0.005); diazepam decreased GESP by 42% (P = 0.005); and fentanyl-droperidol decreased GESP by 40% (P = 0.03). Therefore, esophageal manometric evaluation of gastroesophageal sphincter function should not be preceded by administration of these drugs.