adrenergic agonists (alpha and beta) - Sheet1 (1) Flashcards
What are adrenergic agonists also known as?
Sympathomimetics
What do adrenergic agonists activate?
Sympathetic receptors in the sympathetic nervous system
Name some drugs that are adrenergic agonists.
Norepinephrine, epinephrine, dopamine
What response do adrenergic agonists induce?
Fight-or-flight response
What receptors do adrenergic agonists act on?
Alpha and Beta receptors
What can be the effects of adrenergic agonists?
Therapeutic or adverse, depending on the patient’s condition
What does an alpha1 adrenergic agonist do?
It affects vascular tissue and smooth muscle.
What are the effects of alpha1 adrenergic agonists on the heart?
Increases the force of heart contraction.
How does an alpha1 adrenergic agonist affect blood pressure?
Causes vasoconstriction, which increases blood pressure.
What effect does an alpha1 adrenergic agonist have on pupils?
Dilates pupils (mydriasis).
How does an alpha1 adrenergic agonist affect GI secretions?
Decreases GI secretions.
What effect does an alpha1 adrenergic agonist have on the bladder and prostate?
Increases contraction of the bladder and prostate.
What is the effect of a beta1 adrenergic agonist on the heart?
Increases heart rate and force of contraction.
What effect does a beta1 adrenergic agonist have on blood pressure?
Increases blood pressure.
What does a beta1 adrenergic agonist stimulate in the kidneys?
Increases renin secretion.
Where do alpha2 adrenergic agonists act?
On sympathetic nerve endings.
What does an alpha2 adrenergic agonist do to norepinephrine?
Decreases norepinephrine release.
How does an alpha2 adrenergic agonist affect blood pressure?
Causes vasodilation, which lowers blood pressure.
What effect does an alpha2 adrenergic agonist have on GI motility?
Decreases GI motility.
What are the effects of a beta2 adrenergic agonist on the lungs?
Dilates bronchioles.
What effect does a beta2 adrenergic agonist have on the uterine muscles?
Causes relaxation.
How does a beta2 adrenergic agonist affect arterioles in skeletal muscles, heart, and lungs?
Causes vasodilation.
What effect does a beta2 adrenergic agonist have on blood sugar?
Increases blood sugar through glycogenolysis.
What does a dopamine agonist do to the kidneys?
Causes renal vasodilation, increasing renal perfusion.
What are catecholamines?
Adrenergic agonists that are short-acting and must be given IV.
What are some catecholamine drugs?
Epinephrine, dopamine, dobutamine, isoproterenol, norepinephrine
What are noncatecholamines?
Adrenergic agonists that have longer duration and can be given orally.
What are some noncatecholamine drugs?
Albuterol, ephedrine
What receptors does epinephrine act on?
Alpha1, Beta1, Beta2
What are the alpha1 effects of epinephrine?
Vasoconstriction, increased BP, slowed absorption of local anesthesia, decreased nasal congestion, and reduced superficial bleeding.
What are the beta1 effects of epinephrine?
Increased HR, myocardial contractility, AV node conduction, cardiac output, and tissue perfusion.
What conditions does epinephrine treat?
Anaphylactic shock, cardiac arrest, AV block, heart failure, shock.
What receptors does dopamine act on at a low dose?
Dopamine receptors (renal blood vessel dilation).
What conditions is low-dose dopamine used for?
Shock, heart failure, acute kidney injury.
What receptors does dopamine act on at a moderate dose?
Dopamine + Beta1
What effects does moderate-dose dopamine have?
Renal blood vessel dilation, increased HR, contractility, AV node conduction.
What conditions is moderate-dose dopamine used for?
Shock, heart failure.
What receptors does dopamine act on at a high dose?
Dopamine + Beta1 + Alpha1
What effects does high-dose dopamine have?
Renal vasodilation, increased HR, contractility, AV node conduction, vasoconstriction, mydriasis.
What conditions is high-dose dopamine used for?
Shock, heart failure.
What receptor does dobutamine act on?
Beta1
What effects does dobutamine have?
Increased heart rate, myocardial contraction, cardiac output, and AV node conduction.
What condition is dobutamine used to treat?
Heart failure.
How are adrenergic agonists administered?
IV continuous infusion with an IV pump.
How should adrenergic agonist doses be adjusted?
Titrated based on BP.
What should be monitored during adrenergic agonist therapy?
EKG, BP, chest pain, cardiac output, pulmonary capillary wedge pressure, central venous pressure, urine output.
Why is urine output monitored with adrenergic agonists?
Indicates effective perfusion (≥ 30 mL/hr is ideal).
What blood sugar complication can adrenergic agonists cause?
Hyperglycemia (especially epinephrine, isoproterenol, and albuterol).
What is a major risk of alpha1 activation?
Hypertensive crisis, leading to cerebral hemorrhage.
What should be monitored to prevent hypertensive crisis?
EKG and BP.
What is a major risk of beta1 activation?
Dysrhythmias and angina due to increased cardiac workload and oxygen demand.
What should be monitored for beta1 activation complications?
Urine output, EKG, BP, chest pain (angina).
What is a major risk of extravasation of alpha1 agonists?
Necrosis due to vasoconstriction.
What drug is used to counteract necrosis from alpha1 agonists?
Phentolamine (alpha blocker).
What drugs interact with adrenergic agonists?
MAOIs, tricyclic antidepressants, general anesthesia.
What drugs block adrenergic agonist effects?
Alpha and beta blockers.
What are examples of centrally-acting alpha2 agonists?
Clonidine, Guanfacine, Methyldopa
What are centrally-acting alpha2 agonists used for?
Hypertension (HTN), severe pain, ADHD
Why are centrally-acting alpha2 agonists used for ADHD?
They help counteract stimulants and amphetamines, making it easier to sleep.
What are the effects of centrally-acting alpha2 agonists?
Bradycardia, decreased cardiac output, vasodilation.
What are common adverse effects of centrally-acting alpha2 agonists?
Drowsiness/sedation, xerostomia (dry mouth), rebound hypertension, constipation, impotence, gynecomastia, CNS effects.
What is an important caution for using centrally-acting alpha2 agonists?
Pregnancy.
Which centrally-acting alpha2 agonist is safe during pregnancy and lactation?
Methyldopa.
What population is at risk for abusing centrally-acting alpha2 agonists?
Older adults.
