ISSN:
1432-1041
Keywords:
α- and β-blockade
;
systolic time intervals
;
oxprenolol
;
phentolamine
;
man
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Medicine
Notes:
Summary The effects of single oral doses of oxprenolol (20 and 80 mg), phentolamine (20 and 40 mg), and combinations of oxprenolol and phentolamine (80:20 and 20:40 mg, respectively) on blood pressure, heart rate and the systolic time intervals (Q—S2c, PEPc, LVETc and PEP/LVET) have been studied under double-blind conditions in seven healthy volunteers during recumbency and passive tilting. Heart rate was slowed by oxprenolol and slightly increased by phentolamine, but was not affected by either of the combinations. There were only minimal non-significant changes in blood pressure in the subjects, all of whom were normotensive. Of the systolic time intervals, PEPc was most affected: it was prolonged by oxprenolol because of reduction in myocardial contractility, and shortened by phentolamine as a result of the cardiostimulant effect of this compound. When the two drugs were administered in combination, the negative inotropic effects of the β-blocker always predominated. The changes induced by the drugs were more pronounced during upright titling than in the recumbent position. Measurement of PEPc provides a suitable means of assessing the influence of cardiovascular drugs on left ventricular function in pharmacological studies in man.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00614383
