The Journal of pharmacology and experimental therapeutics
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J. Pharmacol. Exp. Ther. · Nov 1984
Treatment of ventricular tachyarrhythmias resulting from amitriptyline toxicity in dogs.
This study was designed to analyze the effects of lidocaine and sodium bicarbonate on ventricular arrhythmias resulting from amitriptyline infusion in dogs. Amitriptyline was infused i.v. at 0.5 mg/kg/min for 30 min, followed by 1 mg/kg/min to dogs anesthetized with morphine and alpha-chloralose. When arrhythmia occurred, the infusion rate was reduced by one-third and the effect of various interventions studied. ⋯ Administration of hypertonic sodium chloride in equimolar quantities to sodium bicarbonate failed to affect amitriptyline-induced ventricular arrhythmias significantly, but hyperventilation to a pH similar to that produced by sodium bicarbonate (7.48) significantly reduced the frequency of amitriptyline-induced ventricular ectopy. When amitriptyline was infused into dogs ventilated with various respiratory rates, ventricular arrhythmia resulted in 18 of 18 (100%) dogs with pH less than 7.42, 2 of 4 (50%) dogs with pH between 7.48 and 7.51 and 0 of 8 (0%) dogs with a pH between 7.59 and 7.65 (P less than or equal to .001). These results suggest that sodium bicarbonate is effective treatment for amitriptyline-induced cardiac arrhythmias with beneficial effects largely due to alkalinization.(ABSTRACT TRUNCATED AT 250 WORDS)