Adrenergic Drugs Flashcards
Epinephrine Uses
Anyphylactic shock, asthmatic attacks, cardiac arrest, local anesthetics
Norepinephrine Uses
Tx shock bc it incrases vascular resistance and increases BP
*dopa is better bc it doesn’t dec blood flow to the kidney
Dopamine Uses
Tx severe CHF, cardiogenic and septic shock, management of shock
(Based on doses dopamine activates D1 > β1 > α1)
Fenoldopam
Selective D1 agonist
Use: tx HTN
Isoproterenol
β1 and β2-agonist
Effects: bronchodilator (β2), increased HR (β1), decreases peripheral resistance by dilating skeletal m arterioles (β2)
Use: in ED so stimulate HR in pt w/ bradycardia or heart block
Dobutamine
Selective β1-agonist
MOA: potent inotrope w/ mild chronotropic effects
Effects: mild vasodilation, increases myocardial O2 consumption
Use: acute heart failure, cardiogenic shock
*given for stress echo bc it increases cardiac O2 consumption
Albuterol and Terbutaline
Short-acting β2-agonists
Use: asthma
Salmeterol and Formoterol
Long-acting β2-agonist (12h)
Use: not suitable for prompt relief of breakthrough bronchospasm attacks (prophylaxis)
SE: tremor, restlessness, anxiety, tachycardia, apprehension
Phenylephrine
Selective α1-agonist
Effects: vasoconstriction
Use: nasal decongestant, mydriatic, increase BP in hypotension resulting form vasodilation in septic shock or anesthesia, terminates supraventricular tachycardia
Clonidine
Partial α2-agonist (central receptors)
Effects: reduces sympathetic outflow, reducing BP
SE: lethargy, sedation, xerostomia
Methyldopa
α2-agonist
MOA: converted to α-methylNE which activates central α2 receptors
Use: decrease BP, drug of choice for tx of HTN during pregnancy
SE: sedation, impaired concentration, xerostomia
Brimonidine
Selective α2-agonist
Effects: reduces aqueous humor production and increases outflow
Use: decrease IOP in glaucoma
Amphetamine
Target: α1 on vasculature and β on heart
MOA: central stimulatory action
Methylphenidate
Chem: analogue of amphetamine
Use: ADHD in children
Tyramine
Found in fermented foods (ripe cheese and chianti wine)
MOA: oxidized by MAO
Effects: precipitates vasopressor episodes if pt is taking MAOI
Cocaine
MOA: blocks reuptake of monoamines in cleft
Effects: potentiation and prolongation of central and peripheral actions
Atomoxetine
MOA: selective inhibitor of NE reuptake transporter
Use: ADHD
Modafinil
Chem: psychostimulant
MOA: inhibits NE and dopa transporters
Effects: increases concentration of NE/dopa/serotonin/Glu in synapse and decreases GABA levels
Use: narcolepsy
Ephedrine
Chem: has CNS effects
Target α and β, releasing NE from nerve endings
MOA: long duration
Effects: increases BP, bronchodilation, increases alertness, decreases fatigue
Uses: pressor agent during spinal anesthesia when hypotension occurs frequently
Pseudoephedrine
Chem: ephedrine enantiomer
Use: otc as decongestant
Phenoxybenzamine
Irreversible α-antagonist
Use: pheochromocytoma prior to surgery, or chronic management of pheochromocytoma
Phentolamine
Reversible α1 and α2 antagonist
Use: pheochromocytoma tx during surgery, blocking test to dx pheo, prevention of dermal necrosis after extravasation of NE, HTN crisis d/t stimulant OD, tx cocaine induced coronary syndrome, HTN crisis d/t Clonidine withdrawal or sympathomimetic amines
Prazosin
Selective α1-antagonist
Use: tx HTN
Terazosin and Doxazosin
α1-antagonists w/ longer t1/2 than Prazosin
Use: tx HTN and BPH
Tamsulosin
Selective α1A receptor antagonist
Use: BPH
(little effect on PB, less likely to cause orthostatic hypotension)
Yohimbine
α2-antagonist
Use: tx ED (in the past but replaced by phosphodiesterase type 5 inhibitors)
Propranolol / Nadolol
β-antagonist
Atenolol / Metoprolol
Selective β1-antagonist
Indication: HTN pt w/ impaired pulmonary fxn, DM HTN pt’s who are receiving insulin or oral hypoglycemic agents
USE: HTN, angina pectoris, MI
Labetalol
α1 and β-antagonist
Timolol
Non-selective β-antagonist
Use: decrease IOP in glaucoma
Labetalol
Competitive α1 and β-antagonist (potency = β > α)
Use: HTN
Carvedilol
Competitive α1 and β-antagonist
Use: HTN and CHF
*has antioxidant properties
Pindolol
Partial agonist w/ intrinsic sympathomimetic activity (ISA)
α-methyltyrosine (Metyrosine)
Competitive inhibitor of Tyrosine Hydroxylase
Use: management of malignant pheo or pre-op prep for pheo resection
Reserpine
Irreversibly blocks VMAT
MOA: vesicles cannot store NE and dopa
Effects: gradual decrease in BP and slowing of cardiac rate
Use: tx HTN (in the past)
Tetrabenazine
Reversible inhibitor of VMAT
MOA: presynaptic depletion of catecholamines
Indicated: tx of chorea assoc. w/ Huntington’s Dz
Epinephrine Cardio effects w/ high dose
β1 predominates so increased ventricular contraction, increased HR, and additionally some vasoconstriction by the α1 receptors
Epinephrine Cardio effects w/ low dose
β2 predominates so there is drop in diastolic pressure d/t decrease of peripheral resistance controlled by β2 receptors then HR increases d/t β1
Epinephrine Metabolic Effects
Increase glycogenolysis in liver (β2) Increase lypolysis (β1 and β2)
NE w/ pre-tx of Atropine
Causes tachycardia when NE is given after Atropine
Norepinephrine
Potent agonist of α1, α2, β1 (little effect on β2)
Effects: vasoconstriction (α1), increase BP, baroreceptor reflex initiated d/t incrase in BP inducing rise in vagal activity = bradycardia
Dopamine @ Low Infusion Rate
Activates D1 receptors
Target: renal and coronary vessels
Effects: vasodilation in coronary arteries, increase GFR, increase renal blood flow, increase in Na+ excretion
Dopamine @ Intermediate Infusion Rate
Activates β1 receptors in heart increasing CO so inc SBP and increased MAP
*(preservation of flow in heart and kidneys)
Dopamine @ High Infusion Rate
Activates vascular α1 receptors causing vasoconstriction and a rise in BP to maintain BP in shock
Contraindications of β2 blockers?
Asthmatics, vasospastic dz (raynaud or Prinzmental angina), and DM pt’s
