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Acute effect of labetalol on blood pressure in relation to the sympathetic nervous system and plasma renin activity
Author(s) -
Vlachakis Nicolas D,
Barr John,
Velasquez Manuel,
Alexander Natalie,
Maronde Robert
Publication year - 1984
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1984.112
Subject(s) - labetalol , plasma renin activity , sympathetic nervous system , blood pressure , renin–angiotensin system , medicine , sympathetic activity , anesthesia , heart rate
A single oral dose of 300 mg labetalol was given to 10 subjects with uncomplicated primary hypertension; its effects on blood pressure, heart rate (HR), plasma renin activity (PRA), and plasma concentration of catecholamines and of their major metabolites, octopamine (OTP), and dopamine‐β hydroxylase (DbH) were investigated. Although HR did not change after dosing, both systolic and diastolic blood pressure decreased in 2 hr and remained below control up to 12 hr. There was symptomatic orthostatic hypotension in two subjects in the first 2 hr after dosing. PRA decreased in the first 2 hr and followed a gradual rise that became significant at 24 hr. Although DbH did not change, plasma concentrations of norepinephrine (NE) and its major metabolites and of OTP increased between 2 and 4 hr after dosing and remained elevated up to 12 hr. There was no correlation between change in blood pressure and control levels or changes of PRA or NE concentrations. Clinical Pharmacology and Therapeutics (1984) 35 , 782–787; doi: 10.1038/clpt.1984.112