CARDIOVASCULAR PHARMACOLOGY
MNA Program
Fall 1999

Last updated 04/10/00 12:26 PM

3. Your patient has been treated for many years with propranolol to control his hypertension.  Explain why abrupt withdrawal of the ß-blocker would be deleterious in terms of the cardiovascular reflexes and cellular mechanism(s) that underlies these effects.

Due to the many years of continued use of propranolol, the ß receptors have up-regulated.  Therefore with an abrupt withdrawal you are going to have an increased number of free ß receptors.  That may cause a rebound hypertension.  Patient should be tapered off ß blockers therapy in order to avoid precipitation of arrhythmias.  

Cellular mechanisms due to free ß1 receptors include an in SNS NE, HR, contractility, possible chest pain do to myocardial demand.


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