Evaluation of the effects of the opioid agonist morphine on gastrointestinal tract function in horses

Pedro Boscan Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA 95616.

Search for other papers by Pedro Boscan in
Current site
Google Scholar
PubMed
Close
 DVM, PhD, MSc
,
Linda M. Van Hoogmoed Comparative Gastroenterology Laboratory, Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616.

Search for other papers by Linda M. Van Hoogmoed in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Thomas B. Farver Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616.

Search for other papers by Thomas B. Farver in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
, and
Jack R. Snyder Comparative Gastroenterology Laboratory, Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616.

Search for other papers by Jack R. Snyder in
Current site
Google Scholar
PubMed
Close
 DVM, PhD

Abstract

Objective—To evaluate the effects of morphine administration for 6 days on gastrointestinal tract function in healthy adult horses.

Animals—5 horses.

Procedures—Horses were randomly allocated into 2 groups in a crossover study. Horses in the treatment group received morphine sulfate at a dosage of 0.5 mg/kg, IV, every 12 hours for 6 days. Horses in the control group received saline (0.9% NaCl) solution at a dosage of 10 mL, IV, every 12 hours for 6 days. Variables assessed included defecation frequency, weight of feces produced, intestinal transit time (evaluated by use of barium-filled spheres and radiographic detection in feces), fecal moisture content, borborygmus score, and signs of CNS excitement and colic.

Results—Administration of morphine resulted in gastrointestinal tract dysfunction for 6 hours after each injection. During those 6 hours, mean ± SD defecation frequency decreased from 3.1 ± 1 bowel movements in control horses to 0.9 ± 0.5 bowel movements in treated horses, weight of feces decreased from 4.1 ± 0.7 kg to 1.1 ± 0.7 kg, fecal moisture content decreased from 76 ± 2.7% to 73.5 ± 2.9%, and borborygmus score decreased from 13.2 ± 2.9 to 6.3 ± 3.9. Mean gastrointestinal transit time was also increased, compared with transit times in control horses.

Conclusions and Clinical Relevance—Morphine administered at 0.5 mg/kg twice daily decreased propulsive motility and moisture content in the gastrointestinal tract lumen. These effects may predispose treated horses to development of ileus and constipation.

Abstract

Objective—To evaluate the effects of morphine administration for 6 days on gastrointestinal tract function in healthy adult horses.

Animals—5 horses.

Procedures—Horses were randomly allocated into 2 groups in a crossover study. Horses in the treatment group received morphine sulfate at a dosage of 0.5 mg/kg, IV, every 12 hours for 6 days. Horses in the control group received saline (0.9% NaCl) solution at a dosage of 10 mL, IV, every 12 hours for 6 days. Variables assessed included defecation frequency, weight of feces produced, intestinal transit time (evaluated by use of barium-filled spheres and radiographic detection in feces), fecal moisture content, borborygmus score, and signs of CNS excitement and colic.

Results—Administration of morphine resulted in gastrointestinal tract dysfunction for 6 hours after each injection. During those 6 hours, mean ± SD defecation frequency decreased from 3.1 ± 1 bowel movements in control horses to 0.9 ± 0.5 bowel movements in treated horses, weight of feces decreased from 4.1 ± 0.7 kg to 1.1 ± 0.7 kg, fecal moisture content decreased from 76 ± 2.7% to 73.5 ± 2.9%, and borborygmus score decreased from 13.2 ± 2.9 to 6.3 ± 3.9. Mean gastrointestinal transit time was also increased, compared with transit times in control horses.

Conclusions and Clinical Relevance—Morphine administered at 0.5 mg/kg twice daily decreased propulsive motility and moisture content in the gastrointestinal tract lumen. These effects may predispose treated horses to development of ileus and constipation.

All Time Past Year Past 30 Days
Abstract Views 255 0 0
Full Text Views 6973 6284 394
PDF Downloads 1352 838 85
Advertisement