Reduced survival after isoprenaline/ dopamine in d,l-propranolol intoxicated rats

toxic effects of β-blocker overdose. Respiratory arrest is the primary cause of death in β-blocker intoxicated rats. 2 The effect of β-adrenoceptor agonists on respiratory and cardiovascular failure in β-blocker overdose was investigated in a model of acute d,l-propranolol (30 mg kg-1h-1) intoxication in spontaneously breathing rats. 3 Neither the aselective, hydrophilic β-agonist isoprena-line (10, 25, 50 μg kg-1 min-1), nor the β1-sel ctive, lipophilic β-agonist flerobuterol (1,3,10 μg kg-1 min-1) and the β2-sel ctive, lipophilic β-agonist clenbuterol (10, 25, 50 μg kg-1 min-1) had any beneficial effect on cardiovascular and respiratory variables or survival time in d,l-propranolol intoxicated spontaneously breathing rats. 4 Isoprenaline (10 μg kg-1 min-1) had no favourable effect on haemodynamic and respiratory variables in artificially ventilated d,l-propranolol intoxicated rats either. 5 Addition of dopamine to isoprenaline resulted in a significant reduction of survival time, primarily caused by a decrease in mean arterial blood pressure, in artificially ventilated d,l-propranolol intoxicated rats. Addition of glucagon to isoprenaline did not affect survival time. 6 Artificial ventilation is the most important supportive measure in d,l-propranolol intoxication in the rat