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

Cellular mechanisms due to free 1 receptors include an in SNS NE, HR, contractility, possible chest pain do to myocardial demand.

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