Sympathetic antagonists Flashcards

1
Q

Phenoxybenzamine

A
  • MOA
  • irreversibly blocks α1 and α2
  • indirect baroreflex activation
  • Effects
  • lowers BP
  • HR rises due to baroreflex activation
  • Clinical
  • pheochromocytoma/high catecholamine states
  • Kinetics, tox, int.
  • irreversible blocker, duration>1 day
  • tox: orthostatic hypotension, tachycardia, myocardial ischemia
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2
Q

Phentolamine

A
  • MOA
  • reversibly blocks α1 and α2
  • Effects
  • blocks α-mediated vasoconstriction, lowers BP, increases HR (baroreflex)
  • Clinical
  • pheochromocytoma
  • Kinetics, tox, int.
  • t1/2 approx 45min after IV injection
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3
Q

Prazosin, doxazosin, terazosin

A
  • MOA
  • block α1 but not α2
  • Effects
  • lower BP
  • Clinical
  • hypertension
  • benign prostatic hyperplasia
  • Kinetics, tox, int.
  • larger depressor effect with first dose may cause orthostatic hypotension
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4
Q

Tamsulosin

A
  • MOA
  • slightly selective for α1A
  • Effects
  • may relax prostatic smooth muscle more than vascular smooth muscle
  • Clinical
  • benign prostatic hyperplasia
  • Kinetics, tox, int.
  • orthostatic hypotension less common with this subtype
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5
Q

Yohimbine

A
  • MOA
  • blocks α2
  • elicits increased central sympathetic activity
  • increased norepinephrine release
  • Effects
  • raises BP and HR
  • Clinical
  • male erectal dysfunction
  • hypotension
  • Kinetics, tox, int.
  • may cause anxiety
  • excess pressor effect if norepinephrine transporter is blocked
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6
Q

Labetalol

A
  • MOA
  • β>α1 block
  • Effects
  • lowers BP with limited HR increase
  • Clinical
  • hypertension
  • Kinetics, tox, int.
  • oral, parenteral
  • tox: less tachycardia than other α1 agents
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7
Q

Propranolol, nadolol, timolol

A
  • MOA
  • block β1 and β2
  • Effects
  • lower HR and BP
  • reduce renin
  • Clinical
  • hypertension, angina, arrythmias, migraine, hyperthyroidism, glaucoma
  • Kinetics, tox, int.
  • oral, parenteral
  • tox: bradycardia, worsened asthma, fatigue, vivid dreams, cold hands
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8
Q

Metoprolol, atenolol, betaxolol, nebivolol

A
  • MOA
  • block β12
  • Effects
  • lower HR and BP
  • reduce renin
  • may be safer in asthma
  • Clinical
  • angina, hypertension, arrythmias, glaucoma
  • Kinetics, tox, int.
  • tox: bradycardia, fatigue, vivid dreams, cold hands
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9
Q

Butoxamine

A
  • MOA
  • blocks β21
  • Effects
  • increases peripheral resistance
  • Clinical
  • no clinical indication
  • Kinetics, tox, int.
  • tox: asthma provocation
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10
Q

Pindolol, acebutolol, carteolol, bopindolol, oxprenolol, celiprolol, penbutolol

A
  • MOA
  • β1, β2, with intrinsic sympathomimetic (partial agonist) effect
  • Effects
  • lower BP
  • modestly lower HR
  • Clinical
  • hypertension, arrythmias, migraine, may avoid worsening of bradycardia
  • Kinetics, tox, int.
  • oral
  • tox: fatigue, vivid dreams, cold hands
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11
Q

Carvedilol, medroxalol, bucindolol

A
  • MOA
  • β>α1 block
  • Effects
  • same as labetalol?
  • Clinical
  • heart failure
  • Kinetics, tox, int.
  • oral, long t1/2
  • tox: fatigue
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12
Q

Esmolol

A
  • MOA
  • β12
  • Effects
  • very brief cardiac β blockade
  • Clinical
  • rapid control of BP and arrythmias
  • thyrotoxicosis
  • myocardial ischemia intraoperatively
  • Kinetics, tox, int.
  • parenteral only, t1/2 approx 10 min
  • tox: bradycardia, hypotension
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13
Q

Metyrosine

A
  • MOA
  • blocks tyrosine hydroxylase
  • reduces synthesis of dopamine, norepinephrine, and epinephrine
  • Effects
  • lowers BP
  • may elicit extrapyramidal effects (due to low dopamine in CNS)
  • Clinical
  • pheochromocytoma
  • Kinetics, tox, int.
  • tox: extrapyramidal symptoms, orthostatic hypotension, crystalluria
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