Plasma level of lidocaine following intraoperative bolus injection and infusion in heart failure

: In two groups of ten patients each (group I: myocardial insufficiency, group II: no myocardial insufficiency) during anaesthesia arterial plasma levels of lidocaine were studied, following iv bolus administration (1 mg./kg. bw) and subsequent lidocaine infusion (2 mg./min.) for 15 minutes. With this dosage, recommended for antiarrhythmic therapy, plasma levels exceeded the therapeutic range in group I and in some patients reached almost toxic levels (10 micrograms./ml.). In group II lidocaine plasma levels were within the therapeutic range (1,5-4 micrograms./ml.). In patients with myocardial insufficiency and/or reduced hepatic metabolism antiarrhythmic therapy with lidocaine has to be performed with significantly reduced dosages; drug monitoring is recommended.