RESUMO
REASONS FOR PERFORMING STUDY: Short duration of analgesia is among the limitations of a single epidural injection with lidocaine in horses. OBJECTIVES: To evaluate the effectiveness and safety of epidural lidocaine in combination with either tramadol or neostigmine for perineal analgesia in horses. METHODS: Epidural catheters were placed in 6 saddle horses that then were given 3 treatments: 2% lidocaine (0.2 mg/kg bwt) alone, 2% lidocaine (0.2 mg/kg bwt) plus tramadol (0.5 mg/kg bwt), and 2% lidocaine (0.2 mg/kg bwt) plus neostigmine (1.0 µg/kg bwt). The order of treatments was randomised. Haemodynamic variables, respiratory rate, rectal temperature, analgesia, motor block and behaviour scores were compared among the 3 treatments. These parameters were determined before drug administration (baseline), at 5, 10, 15, 30, 45, 60, 75 and 90 min, and every 30 min thereafter until loss of analgesia. RESULTS: Duration of analgesia was longer with lidocaine plus tramadol (210 ± 12 min) compared with lidocaine plus neostigmine (150 ± 35 min) or lidocaine alone (70 ± 12 min; P<0.05). All treatments produced mild or moderate motor block without behavioural changes. Other adverse effects were not observed in any of the horses. CONCLUSION AND POTENTIAL RELEVANCE: Further studies are required to demonstrate whether tramadol or neostigmine have a role in the management of post operative pain when coadministered with lidocaine.
