Sympathomimetics Flashcards
mechanism of action
DIRECT: direct activation of adrenoreceptors
INDIRECT: indirect activation via increasing catecholamines
non-selective, direct-acting
activates alpha and beta adrenergic recptors
a1: vasoconstriction, increases BP
b1: increase HR, conduction, contractility
b2: bronchodilation
drug of choice for anaphylaxis
used for cardiac arrest, asthma, COPD, hemostasis
Epinephrine
side effects of epinephrine
hypertension
tachycardia
ischemia
hyperglycemia
epinphrine is added to this to decrease systemic absorption by vasoconstriction
lidocaine
term for agent that increases heart rate
chronotropic
term for agent that increases conduction
dromotropic
term for agent that increases contractility
inotropic
non-selective, direct-acting
activates alpha and beta adrenergic receptors
a1: vasoconstriction, increases BP
b1: increases HR, conduction, and contractility
b2: bronchodilation
used for neurogenic shock, cardiogenic shock (last resort)
Norepinephrine
side effects of norepinephrine
extreme vasospasm tissue necrosis excessive BP increase arrhythmias infarction REFLEX BRADYCARDIA: compensatory decrease in HR in response to increase in BP
has high alpha than beta activity
norepinephrine
non-selective, direct acting
activates alpha, beta, and D1 adrenergic receptors
a1: vasoconstriction, increases BP
b1: increased HR, conduction, and contractility
d1: vasodilation in splanchnic and renal vessels
used for cardiogenic shock, heart failure
SE: CV disturbance, arrhythmias
dopamine
dose-dependent actions of dopamine
LOW dose = 1-5 mcg/kg/min; D1 receptors
MEDIUM dose = 5-15 mcg/kg/min; B1 receptors
HIGH dose = > 15mcg/kg/min; Alpha receptors
dopamine dose for cardiogenic shock
MEDIUM DOSE
beta-non-selective
non-selectively activates beta adrenergic receptors
b1: increases HR, conduction, and contractility
b2: bronchodilation
used previously for asthma
side effects: CV disturbance, arrhythmias
Isoproterenol
selective alpha 1 agonist
a1: vasoconstriction, increases BP
used as nasal decongestant, mydriatic, drug-induced hypotension, orthostatic hypotension, spinal shock
side effects: REBOUND NASAL CONGESTION (rhinitis medicamentosa), supine hypertension, stroke, MI, piloerection, urinary retention
Phenylephrine
pseudoephedrine, oxymetazoline, tetrahydrozoline, midodrine, naphazoline, xylometazoline
ocular administration causes mydriasis WITHOUT cycloplegia (vs. atropine, phentolamine)
Phenylephrine
pseudoephedrine, oxymetazoline, tetrahydrozoline, midodrine, naphazoline, xylometazoline
4 medications that can be used for pregnant hypertensive patients
- hydralazine (for urgency)
- methyldopa (for maintenance)
- nifedipine
- labetalol
selective alpha 2 agonist
a2: decreases central sympathetic outflow (centrally acting vasodilator)
for hypertension, cancer pain, opioid withdrawal
side effect: SEDATION, REBOUND HYPERTENSION (taper use to avoid), dry mouth
Clonidine
used to treat rebound hypertension secondary to clonidine
Phentolamine
selective alpha 2 agonist
a2: decreases central sympathetic outflow
used for pre-eclampsia, gestational hypertension
side effects: sedation, HEMOLYTIC ANEMIA (POSITIVE COOMB’S TEST)
Methyldopa
Guanfacine, Guanabenz, Dexmedetomidine, Tizanadine
also a muscle relaxant
Tizanadine
has more sedating effects
Dexmedetomidine
selective alpha 2 agonist
a2: decreases aqueous humour secretion
used for glaucoma
side effects: blurring of vision, dry mouth, hyperemia and pruritus, eye discomfort
Apraclonidine
Brimonidine
selective B1 agonist
b1: increases HR and contractility
used for acute heart failure, cardiogenic shock
side effects: tachycardia, arrhythmias, tachyphylaxis
Dobutamine
