METABOLIC AND HEMODYNAMIC-EFFECTS OF DOPAMINE PLUS DOMPERIDONE IN VOLUNTEERS

There are no studies of the relationship between infusion rate of dopa mine and the arterial and venous dopamine plasma concentration and the resulting haemodynamic and metabolic effects. Dopamine was administer ed to seven volunteers using five infusion rates (1, 3, 6, 9, 13 mug/k g per minute) in an escalating sequence lasting for 30 min for each st ep. Since dopamine can cause nausea and vomiting, this relationship wa s investigated after administration of domperidone for infusion rates above 3 mug/kg per minute. Haemodynamic effects were assessed using 2- dimensional echocardiography. During the highest infusion rate the art erial plasma dopamine concentration reached 1,379 +/- 181 nmol/l. Ther e was a linear correlation between the dopamine infusion rate and both the arterial and the venous plasma concentration. There was no signif icant change in heart rate or diastolic blood pressure. Systolic blood pressure, ejection fraction and cardiac index increased in a dose-dep endent manner. Systemic vascular resistance decreased during the two l ow doses of dopamine and was not different from baseline values during the three high infusion rates. The plasma concentrations of glucose a nd non-esterified fatty acids increased from 5.3 +/- 0.4 to 6.8 +/-0.9 nmol/l, and from 360 +/- 119 to 971 +/- 307 mumol/l, respectively, du ring the 13 mug/kg per minute infusion rate. As the plasma noradrenali ne concentration increased up to 7.84 +/- 2.46 nmol/l in correlation t o the dopamine plasma concentration, an indirect sympathomimetic effec t may contribute to the actions of dopamine plasma concentration.