antagonists - Sheet1 Flashcards
What does an alpha1 adrenergic antagonist do?
Decreases force of heart contraction, causes vasodilation (↓ BP), constricts pupils, increases GI secretions, and decreases bladder & prostate contraction.
What does a beta1 adrenergic antagonist do?
Decreases heart rate, force of contraction, BP, and renin secretion.
What does an alpha2 adrenergic antagonist do?
Increases norepinephrine release, causes vasoconstriction (↑ BP), and increases GI motility.
What does a beta2 adrenergic antagonist do?
Constricts bronchioles, increases GI and uterine contraction, and increases blood sugar (glycogenolysis).
What are examples of alpha-adrenergic antagonists?
Azosin, prazosin, doxazosin, terazosin, tamsulosin.
What are alpha1 adrenergic antagonists used for?
Hypertension (HTN), benign prostatic hyperplasia (BPH), pheochromocytoma, Raynaud’s disease.
What are adverse effects of alpha1 adrenergic antagonists?
Orthostatic hypotension, reflex tachycardia, nasal congestion, inhibition of ejaculation, sodium retention & increased blood volume.
What is the “First Dose” Effect of alpha1 antagonists?
Severe postural hypotension leading to syncope.
How can the “First Dose” Effect be prevented?
Start therapy with low doses and give the first dose at bedtime.
What are examples of cardioselective (β1) beta-blockers?
Metoprolol, atenolol, esmolol, bisoprolol.
What are examples of nonselective (β1 & β2) beta-blockers?
Propranolol, nadolol.
What are examples of alpha & beta blockers?
Carvedilol, labetalol.
What are the effects of beta-blockers on the heart (β1)?
Lowers heart rate, myocardial contractility, cardiac output, and AV node conduction.
What are the effects of beta-blockers on blood vessels (α1 blockade in some drugs)?
Causes vasodilation.
What are beta-blockers used for?
HTN, angina, tachydysrhythmias, heart failure, MI, hyperthyroidism, migraines, pheochromocytoma, glaucoma.
What is a key nursing consideration for beta-blockers?
If HR is under 50, hold the beta-blocker.
What are adverse effects of beta1 blockade?
Bradycardia, reduced cardiac output, AV block, orthostatic hypotension, rebound myocardial excitation.
What are adverse effects of beta2 blockade?
Bronchoconstriction, inhibition of glycogenolysis.
Why should beta2 blockers be avoided in asthmatics?
They cause bronchoconstriction.
What are key precautions for beta-blockers?
Pregnancy/lactation (risk of neonatal bradycardia, respiratory distress, hypoglycemia).
In what conditions should beta-blockers NOT be used?
AV block, sinus bradycardia, asthma (nonselective), diabetes, bronchospasm, heart failure, depression, hypotension, myasthenia gravis, peripheral vascular disease (PVD), older adults, severe allergies.
