Remifentanil is an ultra-short-acting synthetic opioid analgesic used in veterinary medicine, including equine practice, for its rapid onset and ease of titration. It acts on the mu-opioid receptors to provide analgesia and sedation, making it a useful adjunct in anesthesia protocols for horses. Due to its pharmacokinetic properties, remifentanil is often employed in situations requiring precise control over anesthesia depth and duration. Its effects are quickly reversible, which can be advantageous in managing post-operative recovery. This page compiles peer-reviewed research studies and scholarly articles that explore the pharmacodynamics, administration protocols, and clinical applications of remifentanil in equine anesthesia and pain management.
Fujiyama M, Jones T, Duke-Novakovski T.To evaluate perioperative stress-related hormones in isoflurane-anesthetized horses administered infusions of dexmedetomidine alone or with butorphanol or remifentanil, compared with ketamine-morphine. Methods: Randomized, prospective, nonblinded clinical study. Methods: A total of 51 horses undergoing elective surgical procedures. Methods: Horses were premedicated with xylazine, anesthesia induced with ketamine-diazepam and maintained with isoflurane and one of four intravenous infusions. Partial intravenous anesthesia (PIVA) was achieved with dexmedetomidine (1.0 μg kg hour; group D; 12 hor...
Jones T, Bracamonte JL, Ambros B, Duke-Novakovski T.To evaluate effects of anesthesia induced with alfaxalone and maintained with alfaxalone, dexmedetomidine and remifentanil infusions in foals. Methods: Prospective, experimental study. Methods: A group of six healthy foals [median (range) 11 (8-33) days] undergoing abdominal surgery. Methods: Intravenous (IV) dexmedetomidine (3-7μgkg) provided sedation for insertion of a pulmonary artery catheter. IV anesthesia was induced with alfaxalone (2mgkg) and maintained with alfaxalone (6mgkghour), dexmedetomidine (1μgkghour) and remifentanil (3μgkghour). Foals were endotracheally intubated and lung...
Benmansour P, Billinsky J, Duke-Novakovski T, Alcorn J.To determine blood remifentanil concentration in isoflurane-anesthetized horses during and after a 1h remifentanil and dexmedetomidine infusion. Methods: Prospective study. Methods: Six adult mixed breed horses with (mean±SD) bodyweight of 507±61kg and 14±4years of age. Methods: Following sedation with xylazine IV, anesthesia was induced with ketamine IV mixed with diazepam IV. Anesthesia was maintained with isoflurane in oxygen. After 52±7min for instrumentation, dexmedetomidine (0.25μgkg(-1) followed by 1.0μg(-1)kg(-1)h(-1)) and remifentanil infusions (6μgkg(-1)h(-1)) were administere...
Benmansour P, Husulak ML, Bracamonte JL, Beazley SG, Withnall E, Duke-Novakovski T.To examine the cardiopulmonary effects of infusions of remifentanil or morphine, and their influence on recovery of horses anesthetized with isoflurane and dexmedetomidine. Methods: Randomized crossover study with 7-day rest periods. Methods: Six adult horses (507 ± 61 kg). Methods: After the horses were sedated with xylazine, anaesthesia was induced with ketamine and diazepam, and maintained with isoflurane. After approximately 60 minutes, a dexmedetomidine infusion was started (0.25 μg kg(-1) then 1.0 μg(-1) kg(-1) hour(-1) ) in combination with either saline (group S), morphine (0.15 mg ...
Benmansour P, Duke-Novakovski T.A 10-year old Arabian mare had a slow-growing mass on the lower right mandible and required a large partial mandibulectomy. Methods: No abnormalities were detected apart from the mass. Results: A temporary tracheostomy was performed pre-operatively. Anesthesia was induced with xylazine followed by ketamine and diazepam. For 13 hours, anesthesia was maintained using sevoflurane, dexmedetomidine and remifentanil infusions, with the exception of surgical preparation time. Intra-operatively, ventilation was delivered through the cuffed tracheotomy tube. Heart and respiratory rates, ECG, arterial ...
Lehner AF, Almeida P, Jacobs J, Harkins JD, Karpiesiuk W, Woods WE, Dirikolu L, Bosken JM, Carter WG, Boyles J, Holtz C, Heller T, Nattrass C....Remifentanil (4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic acid methyl ester) is a mu-opioid receptor agonist with considerable abuse potential in racing horses. The identification of its major equine urinary metabolite, 4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic+ ++ acid, an ester hydrolysis product of remifentanil is reported. Administration of remifentanil HCl (5 mg, intravenous) produced clear-cut locomotor responses, establishing the clinical efficacy of this dose. ELISA analysis of postadministration urine samples readily detected fentany...
Benmansour P, Husulak ML, Bracamonte JL, Beazley SG, Withnall E, Duke-Novakovski T.To examine the cardiopulmonary effects of infusions of remifentanil or morphine, and their influence on recovery of horses anesthetized with isoflurane and dexmedetomidine. Methods: Randomized crossover study with 7-day rest periods. Methods: Six adult horses (507 ± 61 kg). Methods: After the horses were sedated with xylazine, anaesthesia was induced with ketamine and diazepam, and maintained with isoflurane. After approximately 60 minutes, a dexmedetomidine infusion was started (0.25 μg kg(-1) then 1.0 μg(-1) kg(-1) hour(-1) ) in combination with either saline (group S), morphine (0.15 mg ...
Fujiyama M, Jones T, Duke-Novakovski T.To evaluate perioperative stress-related hormones in isoflurane-anesthetized horses administered infusions of dexmedetomidine alone or with butorphanol or remifentanil, compared with ketamine-morphine. Methods: Randomized, prospective, nonblinded clinical study. Methods: A total of 51 horses undergoing elective surgical procedures. Methods: Horses were premedicated with xylazine, anesthesia induced with ketamine-diazepam and maintained with isoflurane and one of four intravenous infusions. Partial intravenous anesthesia (PIVA) was achieved with dexmedetomidine (1.0 μg kg hour; group D; 12 hor...
Benmansour P, Duke-Novakovski T.A 10-year old Arabian mare had a slow-growing mass on the lower right mandible and required a large partial mandibulectomy. Methods: No abnormalities were detected apart from the mass. Results: A temporary tracheostomy was performed pre-operatively. Anesthesia was induced with xylazine followed by ketamine and diazepam. For 13 hours, anesthesia was maintained using sevoflurane, dexmedetomidine and remifentanil infusions, with the exception of surgical preparation time. Intra-operatively, ventilation was delivered through the cuffed tracheotomy tube. Heart and respiratory rates, ECG, arterial ...
Benmansour P, Billinsky J, Duke-Novakovski T, Alcorn J.To determine blood remifentanil concentration in isoflurane-anesthetized horses during and after a 1h remifentanil and dexmedetomidine infusion. Methods: Prospective study. Methods: Six adult mixed breed horses with (mean±SD) bodyweight of 507±61kg and 14±4years of age. Methods: Following sedation with xylazine IV, anesthesia was induced with ketamine IV mixed with diazepam IV. Anesthesia was maintained with isoflurane in oxygen. After 52±7min for instrumentation, dexmedetomidine (0.25μgkg(-1) followed by 1.0μg(-1)kg(-1)h(-1)) and remifentanil infusions (6μgkg(-1)h(-1)) were administere...
Jones T, Bracamonte JL, Ambros B, Duke-Novakovski T.To evaluate effects of anesthesia induced with alfaxalone and maintained with alfaxalone, dexmedetomidine and remifentanil infusions in foals. Methods: Prospective, experimental study. Methods: A group of six healthy foals [median (range) 11 (8-33) days] undergoing abdominal surgery. Methods: Intravenous (IV) dexmedetomidine (3-7μgkg) provided sedation for insertion of a pulmonary artery catheter. IV anesthesia was induced with alfaxalone (2mgkg) and maintained with alfaxalone (6mgkghour), dexmedetomidine (1μgkghour) and remifentanil (3μgkghour). Foals were endotracheally intubated and lung...
Lehner AF, Almeida P, Jacobs J, Harkins JD, Karpiesiuk W, Woods WE, Dirikolu L, Bosken JM, Carter WG, Boyles J, Holtz C, Heller T, Nattrass C....Remifentanil (4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic acid methyl ester) is a mu-opioid receptor agonist with considerable abuse potential in racing horses. The identification of its major equine urinary metabolite, 4-methoxycarbonyl-4-[(1-oxopropyl)phenylamino]-1-piperidinepropionic+ ++ acid, an ester hydrolysis product of remifentanil is reported. Administration of remifentanil HCl (5 mg, intravenous) produced clear-cut locomotor responses, establishing the clinical efficacy of this dose. ELISA analysis of postadministration urine samples readily detected fentany...