Canadian Journal of Anesthesia, Vol 24, 371-379, Copyright © 1977 by Canadian Anesthesiologists' Society

Urine Catecholamine Excretion After Large Doses of Fentanyl, Fentanyl and Diazepam and Fentanyl, Diazepam and Pancuronium

¹ Department of Anesthesiology, the University of Utah College of Medicine, 50 North Medical Drive, Salt Lake City, Utah, 84132

The effects of fentanyl (0.5 mg/kg iv), fentanyl with diazepam (1 mg/kg iv) and fentanyl, diazepam and pancuronium (0.1 mg/kg iv) on heart rate (HR), mean arterial blood pressure (BP), cardiac output (Q^·T), urine flow rate and urine epinephrine and norepinephrine excretion were determined in nine dogs. Fentanyl did not significantly change Q^·T or BP but did reduce HR and urine flow rate (P < 0.05). Urine epinephrine and norepinephrine excretion rates were significantly increased by fentanyl (P < 0.05). Diazepam caused no significant further changes in Q^·T, BP or HR 30 minutes after administration, but urine epinephrine and norepinephrine excretion rates were reduced to control (pre-fentanyl) levels. Addition of pancuronium after fentanyl and diazepam increased urine flow rate to prefentanyl levels and elevated Q^·T, BP and HR above controls but produced no significant change in urine epinephrine or norepinephrine excretion. These data suggest that fentanyl increases catecholamine blood levels and imply that the latter may be one mechanism by which cardiovascular dynamics are maintained stable during fentanyl anaesthesia. Our findings also demonstrate that cardiovascular stimulation after pancuronium is not associated with increased urinary catecholamine excretion.