SEDATIVE EFFICACY OF DROPERIDOL AND DIAZEPAM IN THE RAT

Droperidol and diazepam were evaluated for sedative properties in 12 m ale Sprague Dawley rats (Rattus norvegicus). Over a period of several weeks, each rat was treated subcutaneously with 0.5 mg droperidol/kg, 2.0 mg droperidol/kg, 5.0 mg diazepam/kg, 15.0 mg diazepam/kg, and phy siologic saline according to a randomized schedule. After each treatme nt, the animals were evaluated for their response to a series of four common clinical manipulations (tail-vein bleeding, orbital bleeding, t eeth clipping, and toenail bleeding) at five time points over the 90 m in following the injection. Rats were scored on the basis of their res ponses to each manipulation. Response to cardiac puncture was assessed once in each animal immediately prior to euthanasia. Histologic lesio ns associated with subcutaneous and intramuscular administration of th ese drugs were evaluated in a separate group of animals. Results indic ate that both droperidol and diazepam (at either dose) allow easier ma nipulation for toenail bleeding and teeth clipping when compared with saline control. There was no advantage in using these sedatives for ta il-vein bleeding. Orbital bleeding could not be performed humanely wit h either drug. Diazepam at a dose of 15.0 mg/kg allowed humane cardiac puncture. Subcutaneous injection of diazepam or 2.0 mg droperidol/kg resulted in various degrees of inflammation revealed by histologic exa mination, although no clinical signs were associated with these lesion s. Subcutaneous administration of droperidol at a dose of 0.5 mg/kg is recommended for nonpainful, noninvasive manipulations as it provides adequate sedation for most procedures without inducing the subcutaneou s inflammation observed with diazepam or 2.0 mg droperidol/kg. Diazepa m at a dose of 15.0 mg/kg appears to be a humane alternative to genera l anesthesia for cardiac puncture.