Efficacy of epidural lidocaine combined with tramadol or neostigmine on perineal analgesia in the horse.
Authors: DeRossi R, Módolo T J C, Maciel F B, Pagliosa R C
Journal: Equine veterinary journal
Summary
# Editorial Summary Epidural lidocaine offers rapid-onset analgesia for perineal procedures in horses but suffers from a notably short duration of effect—a significant limitation in clinical practice. DeRossi and colleagues investigated whether combining epidural lidocaine with either tramadol or neostigmine could extend analgesia duration, using a randomised crossover design in six saddle horses receiving three treatments: lidocaine alone, lidocaine plus tramadol (0.5 mg/kg), and lidocaine plus neostigmine (1.0 μg/kg). The addition of tramadol substantially prolonged analgesia to approximately 210 minutes compared with 150 minutes for neostigmine and just 70 minutes for lidocaine monotherapy, whilst all combinations produced only mild to moderate motor block and no behavioural disturbances or serious adverse effects. For practitioners managing perineal pain—whether post-operative or diagnostic—tramadol co-administration offers a threefold extension of epidural lidocaine effect without compromising safety, potentially reducing the need for repeated injections during longer procedures. The findings warrant further investigation into tramadol and neostigmine's effectiveness for postoperative pain management in clinical settings, particularly where sustained perineal analgesia is required.
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Practical Takeaways
- •Adding tramadol to epidural lidocaine can triple the duration of perineal analgesia (from ~70 to ~210 minutes), offering practical advantage for surgical procedures in the saddle horse
- •Neostigmine addition provides intermediate benefit if tramadol is unavailable or contraindicated, extending analgesia to ~150 minutes
- •Motor block is manageable with all three protocols, but horses should be monitored post-operatively given the potential for motor dysfunction
Key Findings
- •Epidural lidocaine plus tramadol provided analgesia for 210 ± 12 minutes, significantly longer than lidocaine alone (70 ± 12 min)
- •Epidural lidocaine plus neostigmine provided analgesia for 150 ± 35 minutes, intermediate duration between tramadol and lidocaine monotherapy
- •All three treatments produced mild to moderate motor block without behavioral changes or observed adverse effects
- •Tramadol combination showed superior analgesic duration compared to neostigmine combination for perineal analgesia