Adrenergics Flashcards
Sympathomimetics can be __ acting, ___ acting, ___ and ___ acting
Direct, indirect, mixed
Direct acting sympathomimetics are agonists of ___ receptors
Alpha and beta
Indirect acting sympathomimetics MOAs
Promote NE release, inhibit NE reuptake, or inhibit NE activation
Catecholamine drugs
Dopamine
Norepinephrine
Epinephrine
Catecholamines are administered ___
By injection or inhalation
Catecholamines do/don’t cross the BBB
Don’t
Non-catecholamine sympathomimetics include:
Phenylephrine
Terbutaline
Receptor subtype selectivity depends on subtle changes in the ______ backbone
phenylethylamine
Alpha 1receptors are located in
Vascular smooth muscle
Iris radial muscle
Alpha 1 receptor functions
Vasoconstriction
Mydriasis without cycloplegia
Alpha 2 receptors are located in
Brainstem
Eye ciliary body
Alpha 2 receptor functions
Decrease sympathetic outflow to heart and vasculature
Decrease blood pressure
Decrease aqueous humor secretion
Decrease intraocular pressure (glaucoma)
Beta 1 receptor location
Heart
Beta 1 receptor functions
Cardiac stimulation
Beta 2 receptors locations
Bronchi
Uterus
Beta 2 receptor functions
Dilates bronchioles
Relaxes uterus
Decreases BP via vasodilation
Epinephrine can use which receptors?
Alpha 1
Alpha 2
Beta 1
Beta 2
Effects of epinephrine on vasculature
Reduced cutaneous blood flow
Can decrease (a1, low doses) or increase (B2, high doses) skeletal muscle blood flow
Controls MAP
Increase coronary blood flow (increase NO release)
Decrease renal blood flow
Respiratory effects of epinephrine
Relaxation of bronchial smooth muscle (B2)
Clinical uses of epinephrine
Increase duration of local anesthetic
Anaphylactic shock
Asthma
Topical hemostasis
Cardiac arrest
Frequent use of epinephrine for bronchodilation can cause
Tolerance via adrenergic receptor down regulation
Adverse effects of epinephrine
Hypertension
Arrhythmias
Angina
Necrosis if IV blows
Epinephrine drug interactions
General anesthetics
Alpha and beta blockers - reduce Epi efficacy
MAOIs
Tricyclic antidepressants
Norepinephrine acts on which receptors?
a1, a2, and B1
Clinical uses of norepinephrine
Severe hypotension
Vasopressor for septic shock
Isoproterenol acts on which receptors?
B1 and B2
Dopamine acts on what kind of receptors?
Dopaminergic (D1)
Has smaller effect on B1 and a1
Dopamine cardiovascular effects
Low dose: renal and coronary artery dilation
Medium dose: increase CO and stroke volume (not HR)
High dose: peripheral vasoconstriction, reduces CO by increasing afterload
When all adrenergic receptors are stimulated, which one predominates?
a1
Dopamine increases/decreases urine output
Increases (increased blood flow to kidneys)
Clinical uses of dopamine
Shock/sepsis to maintain BP
Phenylephrine acts on __ receptors
a1
Phenylephrine causes vaso______
Vasoconstriction
Clinical uses of phenylephrine
Nasal decongestant
Vasopressor
Mydriatic
Adverse effects of phenylephrine
Hypertension
Reflex bradycardia
Restlessness
Arrhythmias
Clonidine activates ___ receptors
a2 (presynaptic autoreceptor)
Clonidine MOA
Reduces sympathetic outflow from CNS to heart and blood vessels to lower blood pressure
Terbutaline activates ___ receptors
B2
Clinical uses of terbutaline
Decrease airway resistance in asthmatics
Tocolytic (suppress premature labor by relaxing uterine smooth muscle
Clinical uses of ephedrine
Nasal decongestion
Reversal of anesthesia induced hypotension
Ephedrine is controlled because it can be used to make ___
Methamphetamine
Amphetamine MOA
Promote release of NE and dopamine and inhibit their reuptake
Clinical uses of amphetamine
ADHD (adderall)
Narcolepsy
Adverse effects of amphetamine
Appetite suppression/growth retardation in children
Dependence/withdrawal/abuse
Insomnia
Adrenergic antagonists
Prazosin
Tamsulosin
Propranolol
Atenolol
Alpha 1 blockers clinical uses
Hypertension
Reynauds
BPH
Antidote of alpha 1 antagonist overdose
Beta 1 blocker clinical uses
Hypertension
Angina/MI
Hyperthyroidism
Glaucoma
CHF
Migraine prevention
Alpha 1 blockers
Prazosin
Tamsulosin
Prazosin MOA
Dilation of vessels
Relaxes bladder neck and prostate
Tamsulosin is different from Prazosin because ___
It favors blocking of prostate and bladder smooth muscle with little effect on blood pressure (acts specifically on a1A receptors)
Beta blockers
Propanolol
Atenolol
Propanolol cardiovascular effects
Decrease HR and contractility
Intitially raises BP but long-term reduces BP
Propanolol suppresses release of ___
Renin
Propanolol causes broncho____
Bronchoconstriction
Adverse effects of Propanolol
Fatigue
Coldness
Sexual dysfunction
Bradycardia
Contraindications of propanolol
Diabetes
Heart failure
Asthma/COPD
Why should diabetics not take propanolol?
Decreases glycogenolysis (can’t respond to hypoglycemia)
Atenolol is a B_ selective antagonist
B1
