Summary
THE clinical, pharmacodynamic and haemodynamic effects of combined alpha and beta-blockade induced by the intravenous infusion of labetalol were evaluated in 32 patients with uncomplicated acute myocardial infarction admitted to a coronary care unit. Labetalol infusion induced linear dose-related falls in systemic blood pressure, and a quadratic reduction in cardiac output; heart rate and left heart filling pressure were unchanged. There was a linear reduction in calculated systemic vascular resistance. The pharmacodynamic activity of the drug was closely correlated with the plasma concentration; differences in patient sensitivity resulted in the absence of any simple relationship between pharmacodynamic activity and cumulative intravenous dosage.
These studies demonstrate that balanced alpha and beta-blockade with labetalol in patients immediately following infarction favourably affects some of the major determinants of myocardial oxygen consumption without producing undue depression of left ventricular performance. They also demonstrate the haemodynamic safety of labetalol; however individual patient dose-titration against blood pressure is mandatory if continuous intravenous infusion of the drug is contemplated.
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Silke, B., Nelson, G.I.C., Ahuja, R.C. et al. Pharmacokinetic and haemodynamic studies with labetalol in acute myocardial infarction. Ir J Med Sci 152, 179–186 (1983). https://doi.org/10.1007/BF02954714
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DOI: https://doi.org/10.1007/BF02954714