Anticholinergics, Alpha and Beta Agents and Blockers Flashcards
what are the four “big” anticholinergic effects/side effects?
CAN’T SEE, CAN’T SPIT, CAN’T PEE, CAN’T SHIT
antihistamines, tricyclic antidepressants, and phenothiazine antipsychotics have strong ______ effects
anticholinergic
Atropine
Therapeutic uses
Bradycardia
Asthma/COPD
What are adverse effects of muscarinic antagonists/anticholinergic drugs?
CAN’T SEE - Blurred vision and photophobia, elevation of intraocular pressure (–> glaucoma)
CAN’T SPIT - Xerostomia (dry mouth)
CAN’T PEE - urinary retention
CAN’T SHIT - constipation
Can’t sweat - anhidrosis - can therefore overheat
Tachycardia
CNS effects: hallucinations, delirium
Solifenacin (VESIcare)
Class
Therapeutic Use
Adverse effects
Anticholinergic for OAB
Adverse effects:
Blurred vision
Dysrhythmia
Tolterodine (Detrol, Detrol LA)
Anticholinergic - nonselective muscarinic antagonist
Therapeutic use: OAB
Fewer anticholinergic side effects than Solifenacin (VESIcare)
What are the signs and symptoms of anticholinergic toxicity?
Blurred vision
Photophobia
Mydriasis (dilated pupils)
Dry mouth
Hot, dry, and flushed skin
Hyperthermia
CNS effects (delirium, hallucinations)
Physostigmine
antidote for anticholinergic toxicity
Inhibitor of acetylcholinesterase
Adrenergic agonists
Therapeutic uses
Congestive heart failure
Asthma
Preterm labor (beta 2)
Cathecholamines
Dopamine
Epinephrine
Norepinephrine
Catecholamines cannot be given through this route of administration
PO
Catecholamines have a ____ duration of action
brief
Can catecholamines cross the blood-brain barrier?
No
What advantages do non-catecholamines have over catecholamines?
-Can be given orally
-Metabolized slowly by MAO - longer half-life
-More able to cross the BBB
What receptors does albuterol bind to?
Beta 2
What receptors does Isoproterenol bind to?
beta 1 and beta 2
What receptors does epinephrine bind to?
Alpha 1 alpha 2
Beta 1 and beta 2
As ____ increases, some receptor selectivity is lost
dose
common alpha-1 adrenergic receptor agonists
epinephrine
norepinephrine
dopamine
phenylephrine
dobutamine
Alpha-1 agonists
Therapeutic uses
-Hemostasis (stops bleeding)
-Nasal decongestion
-Adjunct to local anesthesia
-Elevation of blood pressure (vasoconstriction)
-Mydriasis (dilation of pupils)
Alpha-1 agonists
Adverse effects
Hypertension (widespread vasoconstriction)
Necrosis (with extravasation from IV)
Beta 1 Agonists
Therapeutic Uses
Heart Failure
Shock
Bradycardia
Beta-1 activation
Adverse effects
-Tachycardia
-Dysrhythmia
-Angina pectoris (due to increased cardiac oxygen demand)
Beta-2
Therapeutic uses
BETA 2 - TWINS - TWINS OFTEN COME EARLY
-Asthma
-Delay of preterm labor
What are adverse effects of beta 2 activation?
-Hyperglycemia
-Tremor
What happens to urine output if you give a drug that activates dopamine receptors?
Dopamine receptors cause dilation of the vasculature of the kidneys, which increases renal blood flow and urine output. There is NO effect on the bladder though.
Hypotension, bronchoconstriction, and edema of the glottis are all symptoms of _____
anaphylaxis
What is the treatment for anaphylaxis?
IM Epinephrine
Because epi has a short half-life, about 20% of patients will require a second dose 5-15 minutes later
What are therapeutic uses of epinephrine (besides anaphylaxis)?
-Delays absorption of local anesthetic
-Elevates BP
-Mydriasis during opthalmologic procedures
-Restores cardiac function in arrest
What are adverse effects of epinephrine?
Hypertensive crisis
Dysrhythmias
Angina
Necrosis following extravasation
Hyperglycemia
Unlike epi, nor-epi does not activate _____ receptors
beta 1
Does nor-epi promote hyperglycemia?
No, because nor-epi does not activate beta 2 receptors, it does not promote hyperglycemia like epi does.
What is the chemical classification of isoproterenol?
catecholamine
What receptors does isoproterenol bind to?
beta 1 and beta 2
What is the therapeutic use of isoproterenol?
AV heart block
cardiac arrest
What are the adverse effects of isoproterenol?
-Fewer than those of NE or epinephrine
-Tachycardia
-Angina pectoris
-Hyperglycemia (DM pts)
What are drug interactions with isoproterenol?
MAOIs, TCAs, beta-adrenergic blockers
What is the route of administration for Isoproterenol?
IV, IM, intracardiac
What receptors does dopamine activate at LOW doses?
Dopamine only
What receptors does dopamine activate at very high doses?
Alpha1, beta 1, and dopamine
What are the therapeutic uses of dopamine?
-Shock (increases cardiac output, increases renal perfusion)
-Heart failure (increases force and contractability)
What are adverse effects of dopamine?
Tachycardia
Dysrhythmias
Angina
Necrosis with extravasation
Phenylephrine is a _____ agonist
alpha 1
Chemical classification for phenylephrine
Noncatecholamine
What is the therapeutic use of phenylephrine?
Reduces nasal congestion
Albuterol
Receptor Specificity
Beta 2
Albuterol
Chemical Classification
Noncatecholamine
What are the therapeutic applications of alpha blockade?
-Hypertension (lowers blood pressure by blocking alpha 1 receptors on blood vessels, causing vasodilation)
-Reversal of toxicity of alpha 1 agonists
-PROSTATE PROBLEMS: Benign prostatic hyperplasia (reduced contraction of smooth muscle in the bladder neck and prostatic capsule)
Alpha blockers
Adverse effects
Adverse effects from alpha 2 blockers are minor.
Adverse effects of alpha 1 blocker:
Orthostatic hypotension
Reflex tachycardia
Nasal congestion
Inhibition of ejaculation
Blockade of these receptors may cause orthostatic hypotension as follows:
reduced muscle tone in the venous wall –> upon standing blood pools in the veins –> the return of blood to the heart is reduced –> cardiac output is reduced –> the blood pressure drops
Alpha 1 blockers
Why are alpha 1 blockers usually prescribed along with a diuretic?
Alpha 1 blockers may cause a dramatic drop in BP. The kidneys respond to reduced blood flow by retaining sodium and water, so there is an increase in blood volume.
Prazosin:
Receptor Specificity
Therapeutic use
Alpha 1 blocker
Treats hypertension
Beta blockers
Therapeutic uses
Angina pectoris
Hypertension
Cardiac dysrhythmias
Myocardial infarction
Heart failure
Beta blockers
Adverse effects
Bradycardia
Precipitation of heart failure
AV heart block
Rebound cardiac excitation (beta blockers need to be tapered to prevent rebound HTN and tachycardia)
Beta 2 blockers
adverse effects
Bronchoconstriction
Hypoglycemia
Beta 2 blockers should be used with caution is patients with these conditions
Asthma/COPD - Beta 2 blockers can cause bronchoconstriction, which can lead to dyspnea
Diabetes - Beta 2 receptors on the liver and skeletal muscles regulate glycogenolysis –> so beta 2 blockers can lead to reduced glucose in the bloodstream
Propranolol
Receptor Specificity
Propranolol is a NON-SELECTIVE beta-blocker
Propranolol
Adverse effects
Bradycardia
AV heart block
Heart failure
Bronchoconstriction
Inhibition of glycogenolysis
Depression
What education is important for a diabetic who is taking propranolol?
Beta 2 blockade inhibits the production of glucose. Propranolol may also mask the symptoms of hypoglycemia such as anxiety and tremors
Propranolol
Drug interactions
Calcium channel blockers
Insulin
What does it mean for a drug to have a positive inotropic effect?
When a drug has a positive inotropic effect, it enhances the heart’s ability to contract more forcefully, leading to an increase in cardiac output
Atropine
Pharmacological effects
-Mydriasis (dilated pupils) and cycloplegia (blurry vision)
-Increases HR
-Relaxes smooth muscle (bladder and bronchi)
-CNS: Mild excitation to hallucinations and delirium
Anticholinergics
Therapeutic uses
Bradycardia
Asthma/COPD
OAB
Atropine
Drug interactions
Avoid combining atropine with other drugs capable of causing muscarinic blockade
Mechanisms of Adrenergic
Receptor Activation
Direct receptor binding
Promotion of norepinephrine (NE) release
Inhibition of NE reuptake
Inhibition of NE inactivation
This drug treats necrosis caused by extravasation from IV by blocking alpha-1 adrenergic receptors and reversing the vasoconstrictive effects, restoring blood flow and preventing further tissue damage
Phentolamine
Propranolol vs metoprolol
Receptor Specificity
Propranolol is a non-selective beta-adrenergic antagonist, meaning it blocks both beta-1 and beta-2 adrenergic receptors
Metoprolol is a selective beta-1 adrenergic antagonist. It primarily blocks beta-1 adrenergic receptors with a higher affinity, while having less effect on beta-2 receptors.
Why would you choose metoprolol over propranolol in a patient with Asthma/COPD or diabetes?
Metoprolol has a lower risk of bronchospasm and hypoglycemia compared to propranolol due to its beta-1 selectivity.
Beta-2 agonists
Adverse effects
Hyperglycemia
Tremor
Signs of anaphylactic shock
Skin reactions: itching, hives, redness, swelling.
Respiratory symptoms: wheezing, shortness of breath, difficulty breathing.
Cardiovascular symptoms: rapid or weak pulse, low blood pressure, lightheadedness.
Gastrointestinal symptoms: nausea, vomiting, abdominal pain, diarrhea.
Swelling of throat and tongue.
Anxiety, feeling of impending doom.
How do monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) affect catecholamines and non-catecholamines differently?
Catecholamines are susceptible to rapid metabolism by these enzymes, non-catecholamines have structural differences that make them less prone to enzymatic degradation
Signs / Symptoms of Heart failure
“Crackles” may be heard when listening over the lungs with a stethoscope.
When pressure backs up in the vasculature of the lungs, fluid “transudes” into the spaces surrounding the air sacs, causing them to collapse. As the patient breathes in deeply, the air sacs are forced open and this sounds like “crackle.”
Given the above, it makes sense that someone with heart failure would have some shortness of breath, and perhaps low oxygen levels noted when we place a pulse oximeter on their finger. It also makes some sense that they might have an elevated respiratory rate.
Pedal edema (swelling of the feet) occurs in heart failure. It is a result of the release of renin –> angiotensin –> aldosterone. This happens in response to poor perfusion of the kidneys by the failing heart. Aldosterone causes the kidneys to hold on to excess water and sodium. The extra water can accumulate in gravity-dependent areas.
