Large dose of flunitrazepam attenuates baroreflex control of heart rate in man.

The effects of intravenous tranquilizers such as flunitrazepan, diazepam and droperidol on baroreflex control of heart rate were investigated using both pressor and depressor tests. The dose-dependency was also studied by the administration of the drugs at the usual or twofold dosage. The usual dosage caused no significant change in neuronal controlling mechanism of circulation. However, flunitrazepam at double the usual dosage produced a decrease in baroreflex sensitivity at depressor tests. The results suggest that flunitrazepam when given repeatedly might accelerate hemodynamic derangements induced by an acute decrease in blood pressure.