Pharmacokinetics and clinical effects of a subanesthetic continuous rate infusion of ketamine in awake horses

Abstract

Ketamine can be administered to awake horses at 0.4 or 0.8 mg/kg/h without adverse behavioral effects. The observed pharmacokinetic values are different than those reported for single-dose IV bolus administration of this drug.

Neuropathic Pain Management in Chronic Laminitis

“…138 Clinical effects of subanesthetic ketamine infusion (400 and 800 µg•kg -1 •hr -1 ) have been studied in awake horses. 139 During or following the 12 hr infusion no analgesic effects could be demonstrated and no signs of excitement or significant changes in measured physiological variables occurred. A CRI of 400-1500 µg•kg -1 •hr -1 has been used safely in conscious horses.…”

Continuous caudal epidural analgesia for perioperative pain control after bilateral mastectomy in a mare

“…Lidocaine alone or in combination has analgesic and anti-inflammatory effects in the conscious horse (Robertson and others 2005, Cook and others 2009), although central nervous system toxicity and cardiovascular system toxicity have been reported when higher plasma concentrations are reached during long-term therapy with systemic lidocaine in horses (Doherty and Seddighi 2010, Sanchez and Robertson 2014). Some adverse effects (increased heart and respiratory rate, excitation and muscle fasciculation) and ineffective analgesia have been reported in chronic pain studies after ketamine infusion (0.5–1 mg/kg/h) in standing horses (Fielding and others 2006, Muir 2010). To avoid the side effects and the practical implications of lidocaine or ketamine infusions in awake horses (need/care for intravenous catheter, syringe driver, etc), caudal epidural anaesthesia can be considered as an alternative to the use of systemic analgesics.…”

Managing orthopaedic pain in horses

“…Infusions of 0.4 and 0.8 mg/kg/hour have been shown to be tolerated well in conscious horses, with excitement seen at 1.6 mg/kg/hour, although no somatic analgesia was demonstrated (Fielding and others 2006). However, Peterbauer and others (2008) did demonstrate analgesic properties in conscious horses after 0.6 mg/kg intravenous bolus followed by 20 μg/kg/minute infusion.…”