The effects of triazolam on cerebral blood flow and metabolism in the dog

The new benzodiazepine triazolam was given to six initially awake dogs maintained with spinal anaesthesia and mechanical ventilation. Both cerebral blood flow (CBF) and cerebral metabolic rate for O2 (CMRO2) were significantly reduced after the initial dose of 0.1 mg X kg-1 triazolam, and the EEG changed from an awake to a sleep pattern in less than 20 s. CMRO2 was gradually reduced with increasing doses of triazolam (0.3, 1.0, 10.0 and 30.0 mg X kg-1) to 76% of control after the final 30 mg X kg-1 dose. CBF did not decrease further after the initial dose, and the addition of N2O after the final dose did not cause any significant change in CBF or CMRO2. The dogs were hemodynamically stable during the study. Small increases in brain lactate and pyruvate levels, but not in the L/P ratio were the only significant changes in brain metabolite levels. Triazolam appears to be a safe and rapidly acting induction agent in the dog.