Canadian journal of anaesthesia = Journal canadien d'anesthésie
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The purpose of this study was to evaluate the effects of pretreatment with propranolol on the cardio-respiratory toxicity of bupivacaine, either plain or with epinephrine 1:200,000 (5 micrograms.ml-1) added. Adult male Sprague Dawley rats, anaesthetized with intraperitoneal pentobarbital, were divided into four groups. Groups I and III were pretreated with iv propranolol 150 micrograms.kg-1, and Groups II and IV received iv NS as a placebo. ⋯ Addition of epinephrine to the bupivacaine eliminated the protective effect of propranolol. All rats pretreated with propranolol (Group III) or NS (Group IV) died when given bupivacaine with epinephrine. In conclusion, acute propranolol pretreatment reduced the fatal cardiotoxicity due to iv bupivacaine in male Sprague Dawley rats, but the addition of epinephrine 5 micrograms.ml-1 to bupivacaine eliminated the protective effect of propranolol.