Displacement of Nortriptyline and Uptake of 14C‐Lidocaine in the Lung after Administration of 14C‐Lidocaine to Nortriptyline Intoxicated Pigs

Abstract

Six anesthetized Swedish land-race pigs were intoxicated by an i.v. infusion of nortriptyline-hydrochloride (NT) up to a concentration of 4.58 .+-. 0.58 (.hivin.X .+-. SEM [standard error of the mean]) .mu.M in arterial whole blood. A rapid injection of 2 mg/kg by wt. lidocaine-hydrochloride in the right atrium was followed by a rise in arterial whole blood concentration of NT up to a maximum of 7.32 .+-. 0.28 .mu.M NT. Amount displaced NT from the cardio-pulmonary circulation after the 14C-lidocaine bolus, was calculated to be 0.66 .+-. 0.03 .mu.mol. Lung uptake of 14C-lidocaine during 1st pass through the lung was not influenced to any statistically significant degree compared to a control group. First pass uptake was 30 .+-. 8 (.hivin.X .+-. SEM) and 39 .+-. 5%, respectively. The duration of the QRS-complex of the ECG was increased (P < 0.01) during the infusion of NT from 0.07 .+-. 0.01 (.hivin.X .+-. SEM) s to 0.14 .+-. 0.02 s when 250 mg NT-HCl was administered. The QRS-duration was decreased (P < 0.01) after the injection of the 14C-lidocaine bolus to 0.09 .+-. 0.01 s. Mean arterial blood pressure and heart rate decreased slightly during the infusion of NT, but did not change immediately after the 14C-lidocaine bolus. Nortriptyline is a tricyclic antidepressant drug.