CARDIOVASCULAR EFFECTS OF AMITRIPTYLINE IN ANAESTHETIZED DOGS

1. The effect of amitriptyline on cardiovascular variables has been studied in anaesthetized dogs. 2. In small doses (0.25 mg/kg) amitryptyline caused small increases in heart rate, contractility, blood pressure, coronary blood flow and aortic flow. 3. Larger doses produced initial depressant effects on myocardial contractility and rate and blood pressure, which were followed by secondary reflex rises in these measurements. 4. The depressant effects were dose-related and were accompanied by marked increases in coronary flow and smaller increases in aortic flow. 5. The secondary reflex rises in cardiac parameters were abolished by propranolol and that of the blood pressure was much reduced.