Adrenergic Agonists/ Antagonists Flashcards
What is the major function of alpha 1
Vasoconstriction
What is the major function of alpha 2
Decreased release of NE from sympathetic neurons
What is the major function of beta 1
- Increase heart rate
- Increase heart contractility
What is the major function of beta 2
Bronchodilation (lungs)
What does epinephrine effect?
Potent stimulant of alpha and beta adrenergic receptors
What are the effects on epinephrine on blood pressure
Rapid spike in BP
1. Direct myocardial stimulation (positive inotropic effect)
2. Increase in HR (positive chronograph effect)
3. Vasoconstriction in vascular beds (alpha 1)
What are the effects of epinephrine on the myocardium
- Drastically increases myocardial oxygen demand
What are the effects of epinephrine on respiratory tract
- Very potent bronchodilator (beta 2)
What are the metabolic effects of epinephrine
Stimulation of beta 2 receptors increases glycogenolysis
What is the alpha 1 activity of norepinephrine
Vasoconstriction in vascular beds
What is the beta 1 activity of norepinephrine
- Direct myocardial stimulation
- Increase in HR
*less potent than epinephrine
What is the beta 2 activity of norepinephrine
- Very potent bronchodilator
*slightly less potent than epinephrine
What are the therapeutic uses of epinephrine and norepinephrine
- Hypersensitivity reactions (epinephrine)
- Cardiac arrest and post cardiac arrest
- Vasopressor therapy in critical care pharmacotherapy
What are the therapeutic effects beta 1 agonists
Chronotropic and inotropic effects in acute decompensated heart failure
What are the therapeutic uses for beta 2 agonist
Bronchodilation in treatment of asthma
What is the therapeutic use of dobutamine
Used to increase cardiac output in acute decompensated heart failure or cardiogenic shock
*increase HR and contractility
Why is the inhalation adminsitatiron of beta 2 agonist better?
Bc it decreases systemic absorption which can also lead to less side effects
What are the short acting beta 2 agonists
- Albuterol
- Levalbuterol
What are albuterol and levalbuterol used for?
Common agents used in acute treatment of asthma
What are the long acting beta 2 agonists (LABA)
- Salmeterol
*selectivity for beta 2 receptors is 50 fold greater than that of albuterol - Formoterol
What are the ADRS of beta 2 agonists (all types)
- Tremor
- Restlessness
- Tachycardia
- Hypokalemia
What are the therapeutic uses of alpha 1 agonists
- Treatment of hypotension and / or shock to increase systemic vascular resistance
- Nasal decongestant
What are the therapeutic uses of alpha 2 agonists
- Treatment of systemic hypertension
- Decrease intra-ocular pressure
- Central nervous system sedative
- Muscle relaxant
What is phenylephrine used for?
- Add on therapy as a vasopressor in treatment of shock
- Also used as a nasal decongestant
What is midodrine used for
Prodrug
1. Used in the treatment of orhtostatic hypotension
What is the use of Clonidine (alpha 2 agonists)
- Causes decreased release of norepinephrine from sympathetic nerves resulting in a decreased ability to constrict blood vessels
*anti hypertension medication PO
What med is more selective for alpha 2 receptor than Clonidine
Guanfacine
What is Tizanidine used for (alpha 2 agonist)
Muscle relaxant
What is the MOA of amphetamine (adderall)
Increase release of catecholamines from sympathetic nerve terminals
What are the effects on the cardiovascular system while taking aphetamine (adderall)
- Raises both systolic and diastolic blood pressure
- HR is often reflexes slowed
What are the effects of amphetamine (adderall) on the smooth muscle
- Increase contraction of sphincter on urinary bladder
- Can cause relaxation of the gut or stimulation of the gut
What are other therapeutic uses of sympathomimetic drugs
- Shock
- Hypotension
- Hypertension
- CHF
- Nasal de congestion
- Asthma
What is the main effect of alpha 1 antagonists
- Inhibits vasconstriction
- Decreased peripheral resistance = lower blood pressure
- Reflex tachycardia and natural fluid preservation
- Alleviate symptoms of benign prostatic hyperplasia
What is prazosin used for (alpha 1 antagonists)
- Hypertension treatment
What is terazosin used for (alpha 1 antagonists)
- In treatment of hypertension and or BPH
*can only be taken once daily
What is doxazosin used for (alpha 1 antagonist)
- Treatment of hypertension and BPH
What is tamsulosin (flomax) used for (alpha 1 antagonists)
- Treatment of BPH with little effect on blood pressure
- Favors selection of alpha 1 receptors in the prostate
What is a common ADR of Alpha 1 antagonists
- First dose effect
*postural hypotension and syncope - Reflex tachycardia
What are some conditions that beta antagonists aid in? (Beta Blockers)
- HTN
- Ischemic heart disease (coronary artery disease)
- Congestive heart failure
- Arrhythmias
What are the selective beta 1 blockers AABBEMN
- Acebutolol
- Atenolol
- Bisoprolol
- Betaxolol
- Esmolol
- Meataprolol
- Nebivolol
Which non selective beta blockers have alpha 1 antagonistic effects
- Carteolol
- Carvedilol
- Labetalol
*used in treatment for HTN
What are the ARDS of beta blockers
- May exacerbate heart failure in compensated heart failure or acute myocardial infarction
- Bradycardia
- Abrupt discontinuation can increase risk of sudden death
- Difficulty breathing
What beta blockers should you have caution with using other agents that slow conduction through the AV node
- Verapmail
- Digoxin
What are the therapeutic uses of beta blockers
- HTN (not first line)
- Angina
- Chronic heart failure
- Dissecting aortic aneurysm / aortic dissection
