Sympathetics Flashcards
Albuterol, Salmeterol
Direct sympathomimetic
Beta2 > Beta1
Albuterol - acute asthma or COPD
Salmeterol - long term asthma or COPD control
Dobutamine
Direct sympathomimetic
Beta1 > Beta2
Increase CO
Heart failure (inotropic > chronotropic) Cardiac stress testing
Dopamine
Direct sympathomimetic
D1 = D2 > Beta > alpha
Unstable bradycardia
HF
Shock
Lower dose - inotropic and chronotropic Beta effects
High dose - vasconstriction due to alpha effects
Epinephrine
Direct sympathomimetic
Beta > alpha
Use:
Anaphylaxis
Asthma
Open angle glaucoma
Low doses - beta effects
High doses - alpha effects
Much stronger effects at Beta2 receptor than norepinephrine
Fenoldopam
Direct sympathomimetic
D1
Postoperative hypertension
Hypertensive crisis
Vasodilator (coronary, peripheral, RENAL, and splanchnic)
Promotes natriuresis
Can cause hypotension and tachycardia
Isoproterenol
Direct sympathomimetic
Beta1 = Beta2
Beta2 mediated vasodilation
dec. MAP and inc. HR through Beta1 reflex activity
Use: bronchospasm, cardiac arrest, heart block
Electrophysiologic evaluation of tachyarrhythmias
Can worsen ischemia
Midodrine
Direct sympathomimetic
alpha1
Use:
Autonomic insufficiency
Postural hypotension
May exacerbate supine hypertension
Norepinephrine
Direct sympathomimetic
alpha1 > alpha2 > Beta1
alpha1 mediated vasoconstriction –> Inc. MAP –> reflex bradycardia ; causes increase in systolic and diastolic pressures
Use:
Hypotension
Septic shock
Phenylephrine
Direct sympathomimetic
alpha1 > alpha2
Use:
Hypotension (vasoconstrictor)
Ocular procedures (mydriatic)
Rhinitis (decongestant)
Amphetamine
Indirect general agonist
reuptake inhibitor
releases stored catecholamines
Vasoconstriction
Increase CNS stimulation
Use:
Narcolepsy
Obesity
ADHD
Cocaine
Indirect general agonist, reuptake inhibitor
Causes vasoconstriction and local anesthesia
Never give beta-blockers if cocaine intoxication is suspected (can lead to unopposed alpha1 activation and extreme hypertension.
Ephedrine
Indirect general agonist
releases stored catecholamines
Vasoconstriction
Use:
Nasal decongestant
Urinary incontinence
Hypotension
Clonidine, Guanfacine
alpha2 agonist
decrease sympathetic flow in CNS
vasodilation –> dec. TPR, dec. BP
Use:
Hypertensive urgency (limited situations)
ADHD
Touurette syndrome
Adv. Effects: CNS depression Bradycardia Hypotension Respiratory depression Miosis
Alpha-methyldopa
alpha2 agonist
Use:
Hypertension in pregnancy
Adv. Effects:
Direct Coombs + hemolysis
SLE-like syndrome
Phenoxybenzamine
Irreversible (noncompetitive), nonselective alpha blocker
vasodilation —> dec. TPR
Use:
Pheochromocytoma (used preoperatively w/ beta blockers)
Prevent catecholamine (hypertensive) crisis
Adv. Effects:
Orthostatic hypotension
Reflex tachycardia
Phentolamine
Reversible (competitive), nonselective alpha blocker
effects same as phenoxybenzamine
Use:
Give to patients on MAO inhibitors who eat tyramine-containing foods
Adv. Effects:
Orthostatic hypotension
Reflex tachycardia
Prazosin, Terazosin, Doxazosin, Tamsulosin
Selective alpha1 blocker
Use:
Urinary symptoms of BPH
PTSD (Prazosin)
Hypertension (except Tamsolusin)
Adv. Effects:
First dose orthostatic hypotension - begin therapy at night
Dizziness
Headache
Mirtazapine
Selective alpha2 blocker
Use:
Depression
Adv. Effects:
Sedation
Inc. serum cholesterol
Inc. appetite
Beta-blockers
use + actions
Angina pectoris:
decrease HR and contractility (decrease O2 consumption)
MI:
decrease mortality
SVT: metoprolol, esmolol decrease AV conduction velocity (class II antiarrhythmic)
Hypertension:
decrease CO, decrease renin secretion (due to B1-receptor blockade on JGA cells)
HF: decrease mortality (bisoprolol, carvedilol, metoprolol)
Glaucoma: timolol
decrease secretion of aqueous humor
Variceal bleeding: nadolol, propranolol
decrease hepatic venous pressure gradient and portal hypertension
Beta-blockers
Adv. effects
Erectile dysfunction
Cardiovascular adverse effects (bradycardia, AV block, HF)
CNS adverse effects (Seizures, sedation, sleep alterations)
Dyslipidemia (metoprolol)
Asthma/COPD exacerbations
Use with caution in cocaine users due to risk of unopposed alpha adrenergic receptor agonist activity
not contraindicated in diabetics due to risk of making hypoglycemia (benefits outweigh risks)
Beta-blockers
B1 selective
Acebutolol (partial agonist) Atenolol Betaxolol Esmolol Metoroplol
preferred in ptns w/ COPD or asthma
Beta-Blockers
nonselective B1 = B2 antagonists
Nadolol
Pindolol (partial agonist)
Propranolol
Timolol
Cause bronchoconstriction, peripheral vasospasm, and can predispose patients to hypoglycemia`
Nonselective alpha and Beta antagonists
Carvedilol
Labetalol
Nebivolol
combines cardiac-selective B1 adrenergic blockade with stimulation of B3 receptors, which activate nitric oxide synthase in the vasculature
