Circulation, Vol 64, 1130-1134, Copyright © 1981 by American Heart Association
P Bolli, FR Buhler, EA Raeder, FW Amann, M Meier, H Rogg and D Burckhardt
The possibility of beta-adrenoreceptor hypersensitivity after abrupt
withdrawal of long-term therapy (8-18 months) with the slow-release (SR)
formulation of oxprenolol (160-320 mg/day) was assessed in six patients
with uncomplicated essential hypertension. The chronotropic dose 25 of
isoproterenol (the dose that increases the resting heart rate by 25
beats/min), plasma concentration of catecholamines, triiodothyronin and
thyroxin, plasma renin activity and aldosterone, hemoglobin, hematocrit and
oxyhemoglobin dissociation were measured on the last day of oxprenolol SR
intake and 1, 2, 3, 6 and 13 days after abrupt replacement by identical
placebo tablets. The chronotropic dose 25 of isoproterenol (microgram/m2),
which was greater than 25.6 in all patients on the last day of oxprenolol
SR, fell to 4.83 +/- 2.03 on the second day and to 3.50 on the third day
after its abrupt withdrawal and reached a minimal value on the thirteenth
day (2.78 +/- 0.30). Throughout the study, plasma concentrations of
catecholamines, triiodothyronin and thyroxin and oxyhemoglobin dissociation
remained unchanged. Plasma renin activity and plasma aldosterone, which
were suppressed during oxprenolol administration, rose significantly during
placebo, coinciding with a significant fall in hematocrit and hemoglobin.
No major subjective symptoms were reported by the patients. Thus,
hypersensitivity of beta-adrenoreceptor-mediated responses was not
demonstrated after sudden withdrawal of oxprenolol SR.
ARTICLES
Lack of beta-adrenoreceptor hypersensitivity after abrupt withdrawal of long-term therapy with oxprenolol
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