Chp 18 Adrenergic Drugs Flashcards
Adrenergic agonists
Drugs that stimulate and mimic the actions of the sympathetic nervous system (sympathomimetics)
Catecholamines
Substances that can produce a sympathomimetic response. They are either endogenous catecholamines (such as epinephrine, norepinephrine, and dopamine) or synthetic catecholamine drugs (such as dobutamine and phenylephrine).
Adrenergic receptors
receptor sites (located throughout the body) for the sympathetic neurotransmitters norepinephrine and epinephrine
What three classes are adrenergic receptors divided into?
Alpha-adrenergic receptors
Beta-adrenergic receptors
Dopaminergic receptors
Alpha-adrenergic receptors
A type of adrenergic receptors that are further broken down into alpha1 and alpha2 adrenergic receptors which are differentiated by their location on nerves
Where are alpha1 receptors located?
on postsynaptic effector cells (the tissue, muscle, or organ that the nerve stimulates
Where are alpha2 receptors located?
on the presynaptic nerve terminals
What d alpha2 receptors control?
the release of neurotransmitters
Beta-adrenergic receptors
receptors located on postsynaptic cells that are stimulated by specific autonomic nerve fibers. (also broken down into beta1 and beta2)
Where are beta1 receptors located?
primarily in the heart
Where are beta2 receptors located?
in the smooth muscle fibers of the bronchioles, arterioles, and visceral organs.
Dopaminergic receptor
a type of adrenergic receptor located in various tissues and organs and activated by the binding of the neurotransmitter dopamine, which can be either endogenous or a synthetic drug form. (Respond only to dopamine)
What are the alpha-adrenergic agonist responses?
- Vasoconstriction
- CNS stimulation
What are the Beta-adrenergic agonist responses?
- Bronchial, GI, and uterine smooth muscle relaxation
- Glycogenolysis
- Cardiac stimulation
What do dopaminergic receptors do?
Causes dilation of the following blood vessels, resulting in increased blood flow: renal, mesenteric, coronary, cerebral
What are the three ways in which catecholamine drugs can induce a response?
- direct stimulation
- indirect stimulation
- Mixed-acting (combination of direct and indirect)
How do direct-acting sympathomimetic drugs work?
by binding directly to the receptor and causing a physiologic repsonse
How do indirect-acting sympathomimetic drugs work?
by causing a release of catecholamine from storage sites in nerve ending and then binding to receptors causing a physiologic response
How do mixed-acting sympathomimetic drugs work?
by directly stimulating the receptor by binding to it AND indirectly stimulating the receptor by causing the release of stored neurotransmitters from vesicles in the nerve endings.
What does stimulation of alpha-adrenergic receptors on smooth muscles result in?
- Vasoconstriction of blood vessels
- Relaxation of GI smooth muscles (decreased motility)
- Constriction of bladder sphincter
- Contraction of uterus
- Male ejaculation
- Contraction of pupillary muscles of the eye (dilated pupils)
What does cardiac stimulation of beta1-adrenergic receptors on the myocardium, atrioventricular (AV) node, and sinoatrial (SA) node result in?
- Increased force of contraction (positive inotropic effect)
- Increased heart rate (positive chronotropic effect)
- Increased conduction through AV node (positive dromotropic effect)
What does stimulation of beta2-adrenergic receptors on the airways result in?
Bronchodilation (relaxation of the bronchi)
What are some other effects of beta2-adrenergic stimulation?
- Uterine relaxation
- Glycogenolysis in the liver
- Increased renin secretion in the kidneys
- Relaxation of GI smooth muscles (decreased motility)
What are some examples of respiratory conditions that adrenergics are used to treat?
asthma and bronchitis (premature labor)
What is albuerol used for?
acute bronchospasms
What is salmeterol used for?
prevention of bronchospasms NOT management of acute symptoms
What is advair diskus used for?
daily maintenance of bronchospasms
What nasal condition do adrenergics treat and how?
congestion - causes constriction of dilated arterioles and reduction of nasal blood flow, thus decreasing congestion
What are some medication examples of adrenergics that treat nasal congestion?
ephedrine, naphazoline, oxymetazoline, pheylephrine, and tetrahydozoline
What are some ophthalmic conditions that adrenergics treat?
- Temporary relief of conjunctival congestion
- Reduction of intraocular pressure and dilation of pupils: treatment of open-angle glaucoma.
What are vasoactive adrenergics used for?
to support the heart during cardiac failure or shock
also called cardioselective sympathomimetics
What are some common vasoactive sympathomimetic drugs?
dobutamine dopamine ephedrine epinephrine fenoldopam phenylephrine midodrine norepinephrine
What adverse affect may happen when using an intravenous solution containing an adrenergic drug lead to?
infiltration of the solution leading to necrosis from excessive vasoconstriction around the intravenous site.
What is phentolamine often used for?
the treatment of infiltration
infiltration
the diffusion or accumulation (in a tissue or cells) of foreign substances or in amounts in excess of the normal. The material collected in those tissues or cells is called infiltrate.
What are the CNS adverse effects of alpha-adrenergics that can happen?
headache, restlessness, excitement, insomnia, euphoria
What are the cardiovascular adverse effects of alpha-adrenergics that can happen?
palpitations, tachycardia, vasoconstriction, hypertension
What are some miscellaneous adverse effects of alpha-adrenergics that can happen?
loss of appetite, dry mouth, nausea, vomiting, taste changes
What are the CNS adverse effects of beta-adrenergics that can happen?
mild tremors, headache, nervousness, dizziness
What are the cardiovascular adverse effects of beta-adrenergics that can happen?
increased heart rate, palpitations, fluctuations in BP
What are some miscellaneous adverse effects of beta-adrenergics that can happen?
sweating, nausea, vomiting, muscle cramps
What are the drugs that can interact with adrenergics?
Anesthetic drugs Tricyclic antidepressants MAOIs Antihistamines Thyroid preparation
What do adrenergic antagonist do to adrenergics?
directly anatgonize each other, resulting in reduced effects
What are the nursing implications when intravenously administering adrenergics?
- Check IV site often for infiltration
- use clear IV solutions
- Use an infusion pump
- infuse drug slowly to avoid dangerous cardiovascular effects
- monitor cardiac rhythm
What are the nursing implications when administering adrenergics to a patient with chronic lung disease?
- instruct patient to avoid factors that exacerbate their condition
- encourage fluid intake (up to 3000 mL/day if permitted
- educate patients about proper dosing, use of equipment, and equipment care
What should a nurse’s immediate assessment priority be when administering a nebulizer treatment with albuterol?
Monitor SpO2 with a pulse oximeter
What can happen if you administer two adrenergic drugs together?
it may precipitate severe cardovascular effects such as tachycardia or hypertension
What therapeutic effects should you monitor for when administering adrenergics for cardiovascular purposes?
- decreased edema
- increased urinary output
- return to normal vital signs
- improved skin color
- increased LOC (loss of consciousness)
What therapeutic effects should you monitor for when administering adrenergics for asthma purposes?
- return to normal respiratory rate
- improved breathing sounds, fewer crackles
- increased air exchange
- decreased cough
- less dyspnea
- improved blood gases
- increased activity tolerance
