title: A study of the in vitro clinical interaction between lidocaine and premedications using rat liver microsomes.
abstract: In this study, we have investigated the relationship between lidocaine metabolism and premedication, i.e., psychotropic and anti-anxiety agents (diazepam, midazolam), hypnotics (pentobarbital, thiamylal), depolarizing muscular relaxants (vecuronium, pancuronium and suxamethonium), an active anti-hypertensive (clonidine) and an H2 receptor antagonist (cimetidine) using rat hepatic microsomes in vitro. Lidocaine metabolism was noncompetitively inhibited by midazolam (Ki=29.0 microM). Thilamylal was a moderate competitive inhibitor of lidocaine metabolism (Ki=77.8 microM). Pentobarbital, diazepam and cimetidine weakly inhibited lidocaine metabolism formation in a concentration-dependent manner at high substrate concentrations. On the other hand, vecuronium, pancuronium, suxamethonium and clonidine did not inhibit lidocaine metabolism over the therapeutic range. These results show that the interaction between lidocaine and midazolam and thiamylal, catalyzed by a similar cytochrome P450, is of potential importance in toxicological and clinical studies.
authors.affiliation: Institute of Community Medicine, University of Tsukuba, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Nagashima
authors.forename: E
authors.initials: E
authors.lastname: Tanak
authors.forename: S
authors.initials: S
authors.lastname: Inomata
authors.forename: S
authors.initials: S
authors.lastname: Misawa
mesh_terms: D000779:Anesthetics, Local / Q000493:pharmacokinetics / Q000494:pharmacology*; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D000959:Antihypertensive Agents / Q000494:pharmacology*; D003577:Cytochrome P-450 Enzyme System / Q000494:pharmacology; D004347:Drug Interactions; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008012:Lidocaine / Q000493:pharmacokinetics / Q000494:pharmacology*; D008297:Male; D008862:Microsomes, Liver; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000779:Anesthetics, Local; D014151:Anti-Anxiety Agents; D000959:Antihypertensive Agents; D006635:Histamine H2 Antagonists; D006993:Hypnotics and Sedatives; D009467:Neuromuscular Depolarizing Agents; D003577:Cytochrome P-450 Enzyme System; D008012:Lidocaine