title: Efficacy of concurrent epidural administration of neostigmine and lidocaine for perineal analgesia in geldings.
abstract: OBJECTIVE
  To evaluate perineal analgesic effects of 3 doses of neostigmine coadministered epidurally with lidocaine to geldings.
  
  
  METHODS
  6 healthy geldings.
  
  
  METHODS
  A few days before each treatment, a catheter was inserted between the first and second coccygeal vertebrae via the caudal approach in each gelding; the catheter tip was threaded approximately 10 cm cranial into the midsacral region. Each horse received 4 epidural treatments: 2% lidocaine (0.2 mg/kg) alone and 3 doses of neostigmine (0.5, 1, or 2 μg/kg) coadministered with that same dose of lidocaine. Horses were restrained in stocks in a standing position. Heart rate, blood pressure, respiratory rate, rectal temperature, intestinal motility, analgesia, behavior, and ataxia were determined before treatment (time 0; baseline); at 5, 10, 15, 30, 45, 60, 75, and 90 minutes; and every 30 minutes thereafter until the cessation of analgesia.
  
  
  RESULTS
  All doses of neostigmine coadministered with lidocaine improved and extended the duration of analgesia in the perineal region of the geldings. Total duration of analgesia was not a dose-dependent effect (120, 150, and 150 minutes for 0.5, 1, and 2 μg/kg, respectively). All treatments induced mild or moderate ataxia. Cardiovascular changes were within acceptable limits.
  
  
  CONCLUSIONS
  Administration of neostigmine (1 μg/kg) combined with lidocaine (0.2 mg/kg) in the caudal epidural space induced analgesia for 2.5 hours with a low prevalence of adverse effects in standing conscious geldings. Epidural doses of neostigmine greater than these should be avoided because they may cause undesirable effects in geldings.
authors.affiliation: Department of Veterinary Medicine, Surgery and Anesthesiology, Faculty of Veterinary Medicine and Animal Science, Federal University of Mato Grosso do Sul, Caixa Postal 549, Campo Grande, 79070-900, MS, Brazil. rafael.rossi@ufms.br
authors.forename: Rafael
authors.initials: R
authors.lastname: DeRossi
authors.forename: Felipe B
authors.initials: FB
authors.lastname: Maciel
authors.forename: Tiago J C
authors.initials: TJ
authors.lastname: Módolo
authors.forename: Ronaldo C
authors.initials: RC
authors.lastname: Pagliosa
mesh_terms: D015360:Analgesia, Epidural / Q000379:methods / Q000662:veterinary*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D001259:Ataxia / Q000662:veterinary; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology; D002800:Cholinesterase Inhibitors / Q000008:administration & dosage*; D004359:Drug Therapy, Combination / Q000662:veterinary; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006736:Horses / Q000502:physiology*; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D009388:Neostigmine / Q000008:administration & dosage*; D012119:Respiration; D018709:Statistics, Nonparametric
chemical_list: D000779:Anesthetics, Local; D002800:Cholinesterase Inhibitors; D009388:Neostigmine; D008012:Lidocaine