Beta Blockers Flashcards
Where are Beta adrenergic receptors found in the heart
Beta 1 and 2 receptors are found in the sinoatrial node, in ectopic pacemakers, and also in contractile muscle fibers.
Beta 2 by itself is found in skeletal muscle vessels and is responsible for relaxing skeletal muscle.
What is the relationship between beta blockers and the JGA in the kidney
Beta receptors on the JGA stimulate the release of renin when activated. beta blockers therefore block renin release
What are the effects of Beta blockers on norepinephrine and epinephrine actions
Beta blockers do nothing to the action of norep and ep
Beta blockers prevent isoproteronol from having an effect
true
First Beta Blocker and is it specific or nonspecific
Propanolol, Non-specific
Esmolol, whats so special about it
Ridiculously short half life (.15) which allows you to have very close control of drug levels.
Main beta blockers with membrane stabilizing activity
Propanolol, Acebutolol, Carvedilol
What is the mechanism of the membrane stabilizers
Bind and block fast Na channels which are responsible for the rapid depolarization of cardiac potentials. Decreases the amplitude of action potentials
ISA
intrinsic sympathomimetic activity
ISA drugs?
Pindolol and acebutolol
What does ISA mean they can do?
These drugs can stimulate the heart to provide relief from bradycardia (slow heart rate..under 60).
Pure sympathetic antagonist
propanolol
Beta blockers that have extended action as Alpha one receptor antagonists
Carvedilol, Labetalol
Antagonists with extended action as Calcium entry blockers
Carvedilol and betaxolol
Antagonists with extended action as nitric oxide producers
Cartelol, Nebivolol
Beta blockers don’t reduce bp in normotensive pts but do so in pts with hypertension
true
What Beta blocker is used to decrease renin when renin is elevated
propanolol
What drug has no effect on renin release
Pindolol
Long term effects of beta blockers?
Decrease vascular resistance
Beta blockers and CHF
BBs may lead to CHF in pts with predisposing heart conditions
BBs and bradycardia
Can be a problem in pts wth AV node conduction defects
BBs can lead to cold extremities from decreased peripheral vascular flow
true
When coming off a beta blocker should the dose be decreased gradually or abruptly
Gradually. Abrupt stoppage after long-term treatment can lead to angina and increase risk of death.
Off target pulmonary effects
Blockade of bronchial smooth muscle beta 2 receptors can lead to bronchoconstriction and life threatening airway resistance in pts with bronchospastic disease