: Sedative doses of hydroxyzine or pentobarbital were tested in healthy volunteers in whom a challenging dose with mephentermine was employed to bring out subtle effects of these two drugs on the cardiovascular system. Both pentobarbital and hydroxyzine had significant cardiovascular effects. Pentobarbital increased systolic blood pressure and cardiac output while hydroxyzine decreased heart rate and cardiac output. Only hydroxyzine modified the effect of mephentermine on the circulation.
(C) 1966 American Society of Anesthesiologists, Inc.