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Biphasic pattern of hypersensitivity following acute propranolol withdrawal in normal subjects
J J Krukemyer1, H Boudoulas, P F Binkley
1Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee, Memphis.
Abstract:
The effect of abrupt propranolol withdrawal on exercise-induced changes in heart rate and blood pressure was studied in six normal volunteers. Response to exercise was measured on two occassions during propranolol treatment and 1, 2, 3, 4, 5 and 7 days after the last dose of propranolol. Exercise-induced changes in heart rate were significantly lower than control during propranolol treatment (p less than 0.005). Following propranolol cessation, all subjects showed a biphasic pattern of hypersensitivity. Heart rate response was significantly greater than control 2, 3 and 7 days after the last propranolol dose (p less than 0.05) and not significantly different from control 1, 4 and 5 days after the last dose of propranolol. Exercise-induced changes in pulse pressure showed a biphasic pattern similar to the changes in heart rate.