Possible Interaction: Epinephrine and Labetalol

“ Adrenaline induced T wave flattening and QTc prolongation were also prevented by labetalol.”

“Pretreatment with labetalol completely blocked adrenaline induced hypokalaemia (3.92-3.95 mmol(mEq)/l).”

“The rise in systolic blood pressure and the fall in diastolic blood pressure observed after the infusion of adrenaline (0.06 micrograms/kg/min) were prevented by labetalol and no increase in blood pressure was seen.”

“Thus labetalol can prevent the electrocardiographic, haemodynamic, and hypokalaemic effects of increased circulating adrenaline in man.”

“3 During psychic stress the plasma concentration of adrenaline rose significantly by 135% after labetalol , by 110% after metoprolol and by 83% after propranolol.”

“We now report that significant direct interference of labetalol in the HPLC-ECD assay does indeed occur, and can yield spuriously raised adrenaline levels.”

“6 Since in the presence of la etalol bo th noradrenaline and adr enaline pr ofoundly reduce heart rate and cardiac output whilst increasing blood pressure, it may be unwise to use either of these catecholamines alone if attempts are being made to reverse excessive hypotension from labetalol overdose.”

“Plasma concentrations of noradrenaline and adrenaline after exogenous infusion were increased after labetalol compared with those levels before labetalol.”