Neuroleptic Effects of Flunitrazepam in Dogs

Experiments were performed to investigate the n.euroleptic and circulatory effects following administration of flunitrazepam (Flu.), a new benzodiazepine delivertive, in comparison to diazepam (Dia.) . Twenty-eight adult mongrel dogs were divided into five groups, and these drugs were administrated intravenously (Flu. 0.3 and 0.1 mg/kg, and Dia. 3.0 mg/kg) and intramusculary (Flu. 0.5 and 0.3 mg/kg) . Physical status, systemic blood pressure, electrocardiogram, arterial blood gas tension, and arterial blood pH were investigated before and after administration of the drugs.The results were as follows:1. The neuroleptic effect of Flu. 0.3 mg/kg i.v. was better than that of Flu. 0.1 mg/kg i.v. and Dia. 3.0 mg/kg i.v.2. After administration, salivation was found 12.5% in Flu. groups and 75% in Dia. group.3. Systolic blood pressure transiently decreased immediately after administration in each group.4. Heart rate increased immediately after injection in each group, but it was not significant in Flu. groups, while it decreased significantly after increasing in Dia. group.5. Less obvious changes in electrocardiogram were found in all groups.6. No significant change in body temperature was seen in Flu. i.v. group, whereas a significant decrease occurred in Flu. i.m. and Dia. i.v. groups.7. Respiration rate increased in each group immediately after administration, thereafter decreased.8. Both Flu. and Dia. gave rise to slight decrease of ventilation volume accompanied with changes of arterial blood pH and gas tension.