Physiological and analgesic effects of continuous-rate infusion of morphine, butorphanol, tramadol or methadone in horses with lipopolysaccharide (LPS)-induced carpal synovitis

• Published in: BMC veterinary research Vol. 10; no. 1; p. 966
• Main Authors: Carregaro, Adriano B, Freitas, Gabrielle C, Ribeiro, Martina H, Xavier, Nathalia V, Dória, Renata GS
• Format: Journal Article
• Language: English
• Published: England Springer-Verlag 21.12.2014; BioMed Central Ltd; BioMed Central
• Subjects: analgesia; Analgesia - methods; Analgesia - veterinary; Analgesics, Opioid - administration & dosage; Analysis; Animals; body temperature; butorphanol; Butorphanol - administration & dosage; Carpal Joints; digestive system; Health aspects; Horse Diseases - drug therapy; Horses; Infusions, Intravenous - veterinary; intravenous injection; lameness; Lameness, Animal; lipopolysaccharides; Lipopolysaccharides - pharmacology; methadone; Methadone - administration & dosage; Morphine; Morphine - administration & dosage; Pharmaceutical industry; Physiological aspects; synovitis; Synovitis - chemically induced; Synovitis - drug therapy; Synovitis - veterinary; Tramadol - administration & dosage; United States
• ISSN: 1746-6148; 1746-6148
• DOI: 10.1186/s12917-014-0299-z

BACKGROUND: Continuous-rate infusion (CRI) of drugs results in more stable plasma drug concentrations than administration of intermittent boluses, thus providing greater stability of physiological parameters. The aim of this study was to evaluate the physiologic and analgesic effects of the administration of morphine, butorphanol, tramadol or methadone by CRI in horses with induced synovitis of the radiocarpal joint. RESULTS: Increased values of cardiorespiratory parameters and body temperature were observed in all groups after initiation of opioid administration, and these increases were sustained throughout the CRI period. Morphine, butorphanol and methadone each caused a reduction in gut sounds, and this effect was greatest in animals that received morphine. Administration of morphine or methadone reduced the degree of lameness after the end of intravenous infusion. Administration of tramadol did not alter the degree of lameness in the animals. CONCLUSIONS: CRI of morphine or methadone, but not butorphanol or tramadol, provided analgesia in horses with carpal synovitis. All of these opioids increased cardiovascular and respiratory parameters and reduced gut sounds during CRI.