[Experimental studies on therapeutic modification of sparteine poisoning]

We investigated the influence of an intoxication with sparteine (10 mg/kg X min i.v.) on heart rate, arterial blood pressure, cardiac output, stroke volume and total peripheral resistance in anesthetized rats. The leading feature of the cardiovascular activity of sparteine in rats was a strong bradycardia whereas blood pressure, cardiac output and peripheral resistance only slightly decreased and stroke volume even increased. The death of the rats occurred with a sudden stop of the QRS complexes in the ECG and an abrupt fall of blood pressure. Isoprenaline, orciprenaline, dopamine and prenalterol were compared with respect to their efficacy in reversing sparteine-induced toxicity in rats. Prenalterol proved to be the best antidote on account of its specific action on adrenergic beta 1-receptors. This result was affirmed in two experiments in pigs. Isoprenaline may also be used as an antidote for sparteine but decreases the blood pressure. Vasoconstrictors like dopamine should only be used in sparteine intoxication when a severe fall of blood pressure occurs which can not be overcome by prenalterol or isoprenaline.