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Hypersensitivity to Adrenergic Stimulation after Propranolol Withdrawal in Normal Subjects
- HARISIOS BOUDOULAS, M.D.;
- RICHARD P. LEWIS, M.D.;
- ROBERT E. KATES, Ph.D.; and
- GEORGE DALAMANGAS, M.D.
Abstract
The cardiac response to isoproterenol after propranolol withdrawal was studied in six normal persons. Serial isoproterenol infusions were done before and after oral propranolol administration, 160 mg daily for 2 days. Changes in electromechanical systole corrected for heart rate (QS2I) and pulse pressure were used to assess the inotropic response to isoproterenol, and changes in heart rate were used to assess the chronotropic response. As shown in previous studies, the negative inotropic effect of propranolol lasted only 12 to 15 h, while the negative chronotropic effect lasted 24 to 36 h. After the disappearance of blockade a hypersensitivity to isoproterenol was found 24 to 48 h after propranolol withdrawal in all three measured determinants. The explanation of this phenomenon most likely lies in the nature of adrenergic receptors that become activated during long-term blockade.
Article and Author Information
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▸From the College of Pharmacy and the Department of Medicine, College of Medicine, Ohio State University; Columbus, Ohio.
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Grant support: in part by grants from the Central Ohio Heart Chapter of the American Heart Association; National Heart and Lung Institute Training Grant No. 5 T01 H105968; and Clinical Research Center Grant RR-34, National Institutes of Health.
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▸Requests for reprints should be addressed to Harisios Boudoulas, M.D.; Division of Cardiology, Ohio State University Hospitals, 466 West Tenth Ave.; Columbus, OH 43210.
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- Received March 28, 1977.
- Accepted July 13, 1977.
