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Comparison of the Inotropic and Chronotropic Effects of Metoprolol and Propranolol
Author(s) -
CONRAD KENNETH A.
Publication year - 1981
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1002/j.1552-4604.1981.tb02550.x
Subject(s) - chronotropic , metoprolol , inotrope , propranolol , medicine , cardiology , heart rate , blood pressure
The cardiovascular responses to intravenous doses of isoproterenol were measured in eight male volunteers before and during administration of 50 mg metoprolol, orally every 6 hours and 40 mg propranolol, orally every 6 hours for a total of five doses. The dose of isoproterenol required to produce an increase in heart rate of 25 beats/min (the ID 25 ) was 2.0 ± 1.4 μg before beta blockade, 6.2 ± 4.4 μg during metoprolol, and 44.4 ± 12.0 μ g during propranolol administration. Similar changes in diastolic blood pressure, QS 2 I , preejection period, and preejection period/left ventricular ejection time ratio occurred at the ID 25 during treatment with both metoprolol and propranolol. In volunteers, propranolol produces a much more intense blockade of the inotropic and chronotropic effects of isoproterenol than does metoprolol.