Determination of a sedative dose and influence of droperidol and midazolam on cardiovascular function in pigs.

Twelve pigs were randomly assigned to 1 of 2 groups, droperidol or midazolam, to determine a sedative dose of each drug that would facilitate handling of the pigs. Each pig in the group received all of the test doses with 5-7 d between treatments (droperidol--0.1, 0.3, 0.6 mg/kg, or midazolam--0.25, 0.5, 1.0 mg/kg) and saline (3 mL), i.m. One investigator, unaware of the treatment administered, assessed the time of onset, degree, and duration of sedation. The 0.3 mg/kg dose of droperidol and 0.5 mg/kg dose of midazolam were judged to be the most suitable for sedation and produced similar degrees of sedation, although the onset and duration of sedation was significantly longer for the droperidol group. The effects of these 2 doses on heart rate, respiratory rate, systolic blood pressure, and rectal temperature were assessed in 12 pigs randomly assigned to 1 of the 2 treatments. Respiratory rate decreased significantly with droperidol at 10, 15, and 30 min. Temperature was significantly decreased at 60 min following midazolam. This study demonstrates that 0.3 mg/kg i.m. of droperidol and 0.5 mg/kg i.m. of midazolam induce adequate sedation in pigs with minimal cardiorespiratory changes.