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Normal cardiac output during beta blockade with timolol in hypertensive patients
Author(s) -
Franciosa Joseph A.,
Freis Edward D.
Publication year - 1975
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 - 10.1002/cpt1975182158
Subject(s) - timolol , blockade , beta (programming language) , medicine , adrenergic beta antagonists , cardiology , anesthesia , propranolol , ophthalmology , glaucoma , computer science , receptor , programming language
Data published by this laboratory indicated that the beta adrenergic blocking drugs timolol and propranolol exerted equivalent beta blocking and antihypertensive actions in patients with mild essential hypertension, but that whereas cardiac output fell acutely with both drugs, it returned to normal after 5 wk of treatment with timolol, but remained depressed after propranolol. This preliminary observation needed further confirmation in a larger series of patients. In this study, 11 patients with initial diastolic blood pressures between 90 and 125 mm Hg were given timolol for 5 wk, Hemodynamic measurements were made before and at the end of treatment. Mean heart rate fell from 76.8 to 64.3 bpm (p < 0.001), and blood pressure was reducedfrom 179.4/99 mm Hg to 167.4/93.3 mm Hg (p < 0.02). Cardiac output averaged 6.29 L/min before timolol, and fell to 5.95 L/min (NS) after treatment. Stroke volume increased significantly, while total peripheral resistance was unchanged. These results confirm our earlier observations that timolol is an effective beta adrenergic blocking drug with antihypertensive action that does not reduce cardiac output significantly when given chronically. This drug merits further evaluation in other cardiovascular disorders since it may have advantages over other beta adrenergic blocking drugs.