Do synthetic adrenergic agents interfere with the measurement of endogenous plasma catecholamine concentrations?
OBJECTIVE
It is common to administer synthetic sympathomimetic and sympatholytic agents in the intensive care unit and operating room. The present study examines whether such agents, as well as the products of catecholamine metabolism, interfere with the quantitation of endogenous catecholamines by high-performance liquid chromatography.


METHODS
Samples of drugs and metabolites were assayed before and after alumina extraction and their relative retention times were compared with dopamine, norepinephrine, and epinephrine relative retention times. Blood samples from patients receiving these drugs were also assayed for their interferences with catecholamine determination.


RESULTS
Phenylephrine interfered with the quantitation of epinephrine. Isoproterenol's peak was so delayed it appeared in the following chromatogram. Dobutamine had two small peaks in vitro, whereas in the patient samples only one peak was identified; the other was probably masked by the dopamine peak. Labetalol had one peak when the pure drug was assayed but multiple peaks in patient samples, that were probably caused by metabolites of labetalol.


CONCLUSIONS
Synthetic adrenergic agents and catecholamine metabolites can potentially interfere with the quantitation of the endogenous catecholamines. Thus, it is important to examine whether such interference occurs when conducting high-performance liquid chromatography assays.
Weissman
C
C
Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York 10032, USA.
Jamdar
S C
SC
Soo
E
E
D018663:Adrenergic Agents / Q000493:pharmacokinetics / Q000627:therapeutic use*; D015982:Bias; D002395:Catecholamines / Q000097:blood* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004353:Drug Evaluation, Preclinical; D004347:Drug Interactions; D006801:Humans
D018663:Adrenergic Agents; D002395:Catecholamines