Use of ketamine or lidocaine or in combination for subarachnoid analgesia in goats

Six adult goats were subjected to three treatments with a minimum of a 1-week interval between the treatments. All animals received 3.0 mg kg−1 ketamine (KE), 2.5 mg kg−1 lidocaine (LI) or 1.5 mg kg−1 ketamine and 1.25 mg kg−1 lidocaine (KELI). All the drugs were injected into the lumbosacral subarachnoid space. Analgesia, ataxia, sedation, cardiovascular and respiratory effects, and rectal temperature were recorded at different intervals before (baseline) and after drug administration. The duration of antinociception after subarachnoid ketamine/lidocaine administration was 127 ± 30 min (mean ± S.D.), i.e., more than twice that obtained with ketamine (49 ± 13 min) or lidocaine (66 ± 31 min) alone. After subarachnoid administration of ketamine, lidocaine, and ketamine/lidocaine, all goats had ataxia and subsequent sternal recumbency. None of the treatments significantly altered the cardiovascular and respiratory functions. Treatment with ketamine alone caused mild sedation. Subarachnoid administration of ketamine/lidocaine to goats resulted in longer duration of analgesia of the tail, perineum, hind limbs, flank, and caudodorsal rib areas, than the administration of ketamine or lidocaine alone. A longer duration of analgesia probably occurred as a synergistic effect of the two drugs. Thus, was concluded that this combination could be used subarachnoidally in goats requiring prolonged surgery.