Pharmacokinetics and pharmacodynamics of a new local anesthetic agent.

We compared the effects of local anesthetics procaine, amethocaine (dicaine), bupivacaine, and a new agent RU-1148 on hydrolytic activity of human plasma butyrylcholinesterase. The butyrylcholinesterase-blocking activity of the test substances decreased in the following order: bupivacaine>amethocaine>procaine>RU-1148. The study of the capacity of these agents to form complexes with human plasma proteins and serum albumin showed that RU-1148 in therapeutic concentrations was transported by human serum albumin,beta-globulin, and acid glycoproteins. Study of the mechanisms of pharmacodynamic interactions between clonidine and RU-1148 demonstrated good prospects of their combined use.