pharmacology test 3 Flashcards
drugs that mimic the effects of SNS neurotransmitters
Norepinephrine (NE), Epinephrine (EPI), Dopamine
Alpha1-adrenergic receptors
Located on postsynaptic effector cells (the cell, muscle, or organ that the nerve stimulates)
Alpha2-adrenergic receptors
Located on presynaptic nerve terminals (the nerve that stimulates the effector cells)
Control the release of neurotransmitters
Alpha-Adrenergic Agonist Responses
vasoconstriction and CNS stimulation
Beta1-adrenergic receptors
located primarily in the heart
Beta2-adrenergic receptors
located in smooth muscle of the bronchioles, arterioles, and visceral organs
Catecholamines
produces a sympathetic response
Endogenous: epinephrine, norepinephrine, dopamine
Synthetic: dobutamine, phenylephrine
Catecholamines are metabolized by
Monoamine oxidase (MAO) - wow you know like MAOI’s
Catechol ortho-methyltransferase (COMT)
Adrenergic Drugs Effect
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)
Increased force of contraction (positive inotropic effect)
Increased heart rate (positive chronotropic effect)
Increased conduction through AV node (positive dromotropic effect)
Adrenergic Indications: Respiratory
Bronchodilators: drugs that stimulate beta2-adrenergic receptors of bronchial smooth muscles, causing relaxation, resulting in bronchodilation
Examples: albuterol, ephedrine, epinephrine, formoterol, levalbuterol, metaproterenol, pirbuterol, and salmeterol
Adrenergic Indications: Nasal Congestion
Intranasal (topical) application causes constriction of dilated arterioles and reduction of nasal blood flow, thus decreasing congestion.
Examples: ephedrine, naphazoline, oxymetazoline, phenylephrine, and tetrahydrozoline
Adrenergic Indications: Ophthalmic
Temporary relief of conjunctival congestion (eyes)
Alpha-adrenergic receptors
Examples: epinephrine, naphazoline, phenylephrine, tetrahydrozoline
Reduction of intraocular pressure and dilation of pupils: treatment of open-angle glaucoma
Alpha-adrenergic receptors
Examples: epinephrine and dipivefrin
Adrenergic Indications: Overactive Bladder
Relaxes the detrusor muscle during the storage phase of the bladder fill cycle
Increases bladder storage capacity
mirabegron (Myrbetriq)
Cardiovascular Indications Vasoactive Adrenergics (Pressors, Inotropes)
Also called cardioselective sympathomimetics
Used to support the heart during cardiac failure or shock; various alpha and beta receptors affected
Vasoactive Sympathomimetics (Pressors, Inotropes): Examples
Dobutamine, ephedrine, fenoldopam, midodrine
Dopamine, epinephrine, phenylephrine, norepinephrine
Contraindications for Pressors
known allergy and severe hypertension
Adverse Effects of Alpha-adrenergic Drugs
Headache, restlessness, excitement, insomnia, euphoria
Chest pain, vasoconstriction, reflexive bradycardia, palpitations, dysrhythmias
Anorexia, dry mouth, nausea, vomiting, taste changes
Adverse Effects of Beta-Adrenergic Drugs
Mild tremors, headache, nervousness, dizziness
Increased heart rate, palpitations, fluctuations of blood pressure
Sweating, nausea, vomiting, muscle cramps
Adrenergic Drugs Overdose and Toxicity
From excessive CNS stimulation: seizures
Intracranial bleeding due to extreme elevation of blood pressure
Effective treatment: rapid acting sympatholytic drug. They have short half-lives, thus effects are short-lived
Symptom management and support the respiratory and cardiac systems
Adrenergic Drugs Interactions
Adrenergic antagonists
Anesthetic drugs
MAOIs
Antihistamines
Thyroid preparations
usually has a decreased effect of the meds
Dobutamine
similar to dopamine
Stimulates beta1 receptors on heart muscle (myocardium); increases cardiac output by increasing contractility (positive inotropy), which increases the stroke volume, especially in patients with heart failure.
Intravenous drug; given by continuous infusion
Short term treatment of heart failure. Beta1 selective vasoactive drug. Similar to dopamine but this is synthetic. Can give the patient chest pain, if the patient already has a heart problem it will make it worse.
Dopamine
Naturally occurring catecholamine neurotransmitter
Potent dopaminergic as well as beta1- and alpha1-adrenergic receptor activity
Low dosages: can dilate blood vessels in the brain, heart, kidneys, and mesentery, which increases blood flow to these areas (dopaminergic receptor activity)
Higher infusion rates: improve cardiac contractility and output (beta1-adrenergic receptor activity)
Highest doses: vasoconstriction (alpha1-adrenergic receptor activity)
preferred drug for patients in shock, IV on a titrated line
Epinephrine
Administered in emergency situations – epipen given subQ
One of the primary vasoactive drugs used in many advanced cardiac life support protocols
Can be given to dead people when trying to pull a Frankenstein
“ACLS think epi” -we can give it as long as we need to, there is no stopping point
Norepinephrine (Levophed)
Causes vasoconstriction
Direct-stimulating beta-adrenergic effects on the heart (beta1-adrenergic receptors)
No stimulation to beta2-adrenergic receptors of the lung
Treatment of hypotension and shock
Administered by continuous infusion titrated drip
Phenylephrine (Neo-Synephrine)
Used primarily for short-term treatment to raise blood pressure in patients in shock
Control of supraventricular tachycardias
Vasoconstriction in regional anesthesia
Topical ophthalmic drug: nasal decongestant
Adrenergic Drugs Nursing Implications
logical things also:
lung disease: Encourage fluid intake (up to 3000 mL/day) if permitted.
2 adrenergic drugs together increase effects so watch out for tachycardia and hypertension
Overuse of nasal decongestants may cause rebound nasal congestion or ulcerations.
using multiple adrenergic drugs can cause tachycardia and hypertension
adrenergic therapeutic effects: cardiac
Decreased edema
Increased urinary output
Return to normal vital signs
Improved skin color and temperature
Increased LOC
adrenergic therapeutic effects: respiratory
Return to normal respiratory rate
Improved breath sounds, fewer crackles
Increased air exchange
Decreased cough
Less dyspnea
Improved blood gases
Increased activity tolerance
Adrenergic Blockers
Adrenergic antagonists, sympatholytics
Alpha blockers, beta blockers, or alpha-beta blockers
Alpha 1 – heart
Beta 2 – lungs
Alpha blockers drug effects
Arterial and venous dilation (reduces blood pressure)
Prostate gland and bladder relaxes, decreasing urinary obstruction and BPH
Alpha blockers Indications
Hypertension (especially for those with pheochromocytoma), BPH, Raynaud’s disease, acrocyanosis, and frostbite
Alpha blockers adverse effects
Teach patients about how they’re likely to experience hypotension, orthostatic hypotension, and especially first dose hypotension
Palpitations, orthostatichypotension, tachycardia, edema, chest pain
Dizziness, headache, anxiety, depression, weakness, numbness, fatigue
Nausea, vomiting, diarrhea, constipation, abdominal pain
Incontinence, dry mouth, pharyngitis
Alpha blockers contraindications
Known allergies
Peripheral vascular disease
Hepatic/renal disease
Coronary artery disease
Peptic ulcer
Sepsis
Common Alpha Blockers
Phenoxybenzamine HCl (Dibenzyline)
Phentolamine (Generic)
Prazosin (Minipress)
Terazosin (Hytrin)
Alfuzosin (Uroxatral)
Tamsulosin (Flomax)
Doxazosin (Cardura)
Phentolamine (Regitine)
Alpha Blocker
for hypertension, to establish a diagnosis of pheochromocytoma, and if a vasoconstricting drug has been extraverted it can be used to reverse the effects
contraindicated in MI and coronary artery disease
Tamsulosin (Flomax)
for treatment of BPH and off-label for female patients with kidney stones
contraindicated in patients using drugs for limp dick disease such as sildenafil
causes severe hypotension in those cases
Adverse effects: headache, abnormal ejaculation, rhinitis, and others
Beta1 Receptors are located
primarily in the heart, they’re called cardioselective for this
Beta2 Receptors are located
Located primarily on smooth muscle of bronchioles and blood vessels
beta1 blockers (cardioselective) mechanism of action
Reduce SNS stimulation of the heart
Decrease heart rate
Prolong sinoatrial (SA) node recovery
Slow conduction rate through the AV node
Decrease myocardial contractility, thus reducing myocardial oxygen demand
nonselective beta blockers action
Nonselective beta blockers (beta1 and beta2)
Cause same effects on heart as cardioselective beta blockers
Constrict bronchioles, resulting in narrowing of airways and shortness of breath
Produce vasoconstriction of blood vessels
Other effects
Indications for Beta Blockers
angina, cardioprotective properties, dysrhythmias, migraine headache, hypertension, heart failure, glaucoma (topical)
beta blockers contraindications
Known drug allergy
Uncompensated heart failure
Cardiogenic shock
Heart block, bradycardia
Pregnancy
Severe pulmonary disease
Raynaud’s disease – makes it worse
beta blockers adverse effects
can be given for and cause heart failure
bradycardia, depression, constipation, impotence, fatigue
may interfere with normal signs of hypoglycemia
beta blockers overdose management
Symptomatic and supportive care
Atropine for bradycardia
Cardiac pacing
Vasopressors for severe hypotension
Hemodialysis to enhance elimination in severe overdoses
beta blocker interaction with antacids
decreased absorption, reduced beta blocker activity
beta blocker interaction with antimuscarinics
antagonism, reduced beta blocker effects
beta blocker interaction with digoxin, diuretics and neuromuscular blocking drugs
additive effects, increases bradycardia (dig), hypotension (diuretics), and prolonged neuromuscular blockade
beta blockers and diabetes mellitus
can mask the signs and symptoms of hypoglycemia
Atenolol (Tenormin)
cardioselective beta blocker - oral
Commonly used to prevent future heart attacks in patients who have had one
Hypertension and angina
Management of thyrotoxicosis to help block the symptoms of excessive thyroid activity
Carvedilol (Coreg)
Nonselective beta blocker, an alpha1-blocker, a calcium channel blocker, and possibly an antioxidant
Slows progression of heart failure and to decrease the frequency of hospitalization
Most commonly added to digoxin, furosemide, and angiotensin-converting enzyme inhibitors when used to treat heart failure
Esmolol (Brevibloc)
Very strong short-acting beta1-blocker - IV only
acute situations to provide rapid temporary control of the ventricular rate in patients with supraventricular tachydysrhythmias
Metoprolol (Lopressor)
beta1 blocker
Oral and injectable
Monitoring required when giving IV – must be on tele monitor
Has been shown to increase survival in patients who have had an MI
Propranolol (Inderal)
Prototypical nonselective beta1 and beta2-blocking drug
Tachydysrhythmias, subaortic stenosis, migraine headaches, essential tremor, hypertension, cardioprotective after MI
Oral and injectable form
Sotalol (Betapace)
Nonselective beta blocker - oral
Potent antidysrhythmic properties
Indicated for management of difficult-to-treat dysrhythmias
non selective beta blockers
Carvedilol (Coreg, Coreg CR)
Labetalol (Normodyne, Trandate)
Nadolol (Corgard)
Penbutolol (Levatol)
Pindolol (Visken)
Propranolol (Inderal)
Sotalol (Betapace)
Timolol (Blocadren, Timoptic)
cardioselective beta blockers
Acebutolol (Sectral)
Atenolol (Tenormin)
Betaxolol (Kerlone)
Esmolol (Brevibloc)
Nebivolol (Bystolic)
Metoprolol (Lopressor, Toprol-XL)
beta blockers nursing implications
Assess for allergies and history of COPD, hypotension, cardiac dysrhythmias, bradycardia, heart failure, and other cardiovascular problems.
Any pre-existing condition that might be exacerbated by the use of these drugs might be a contraindication to their use.
Adrenergic-Blocking Drugs: Nursing Implications
change positions slowly
avoid caffeine (excessive irritability)
avoid alcohol ingestion and hazardous activities until blood levels become stable
Instruct patients to notify their physicians if palpitations, dyspnea, nausea, or vomiting occurs.
adrenergic blocking drugs therapeutic effects
Decreased chest pain in patients with angina
Return to normal BP and heart rate
Other specific effects, depending on the use
beta blockers nursing implications
Rebound hypertension if meds stopped abruptly
call doctor if you’re too sick to take the meds
might be a decrease in activity tolerance (bitches get dizzy)
hot tubs and saunas may increase hypotension
call doc if
Weight gain of more than 2 lb in 1 day or 5 lb in 1 week
Edema of the feet or ankles
SOB, fatigue, weakness, syncope, dizziness
Pulse less than 60
Cholinergic Drugs Overview
aka cholinergic agonists or parasympathomimetics
mimick acetylcholine (ACh)
In the CNS functions as an inhibitory neurotransmitter affecting learning, memory, attention
In the peripheral nervous system functions as an excitatory neurotransmitter inducing muscle contraction
parasympathetic response
eyes: constricted pupil
lungs: constricts bronchioles and increase secretions
heart: decreased heart rate
blood vessels: dilate
GI: Increase peristalsis and digestion
mechanism of action: direct-acting cholinergic agonists
binds directly to cholinergic receptors
mechanism of action: indirect-acting cholinergic agonists
Inhibit the enzyme acetylcholinesterase, which breaks down ACh
Results in more ACh available at the receptors
indirect-acting cholinergic agonists reversible vs irreversible
Reversible: bind to cholinesterase for a short period of time
Irreversible: binds to cholinesterase for a long period of time
or binds to cholinesterase and form a permanent covalent bond. The body must make new cholinesterase to break these bonds.
indications for direct acting cholinergic agonists
Reduce intraocular pressure
Useful for glaucoma and intraocular surgery (Acetylcholine, Carbachol)
Pilocarpine – for glaucoma. Given topically.
Depress inner canthus to minimize general absorption