COMPARISON OF THE SEDATIVE AND ANTINOCICEPTIVE EFFECTS OF MIDAZOLAM AND DIAZEPAM IN HORSES (COMPARAÇÃO DOS EFEITOS SEDATIVOS E/OU ANTINOCICEPTIVOS DO MIDAZOLAM E DIAZEPAM EM EQÜINOS)

SUMMARY The aim of this study was to evaluate the antinociceptive and sedative effects of midazolam and diazepam in 10 Thoroughbred mares. The sedative effects of midazolam (0.05, 0.1 and 0.15 mg/kg iv) and diazepam (0.05, 0.15 and 0.25mg/kg iv) were investigated by determination of the spontaneous locomotor activity (SLA) in automated behavior stalls and by measuring the head ptosis (HP). The antinociceptive effect was determined using a heat-projecting lamp by measuring the hoof withdrawal reflex latency (HWRL) and the skin twich reflex latency (STRL). The differences were evaluated by Tukey’s test (p 10 sec) in all animals tested at a dose of 0.15 mg/kg, within 5 min. Midazolam produced a good sedative effect and diazepam a short acting antinociceptive effect.