Efficacy of concurrent epidural administration of neostigmine and lidocaine for perineal analgesia in geldings.

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Efficacy of concurrent epidural administration of neostigmine and lidocaine for perineal analgesia in geldings.

Am J Vet Res. 2012 Sep;73(9):1356-62

Authors: DeRossi R, Maciel FB, Módolo TJ, Pagliosa RC

Abstract
OBJECTIVE: To evaluate perineal analgesic effects of 3 doses of neostigmine coadministered epidurally with lidocaine to geldings.
ANIMALS: 6 healthy geldings.
PROCEDURES: 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 AND CLINICAL RELEVANCE: 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.

PMID: 22924716 [PubMed – indexed for MEDLINE]