Pharmacology Exam #1: Adrenergic Antagonists

adrenergic antagonists

• aka adrenergic blockers or sympatholytics

• classified based on a α/β affinity

α blockers

• antagonists with affinity α₁

• vasodilation = decreased BP

Phenoxybenzamine

• decreased BP

• epi reversal

• Tu: pheochromocytoma

• AE: postural HTN, nausea/vomiting

Phentolamine

• DOA: 4 hours

• TU: pheochromocytoma

• AE: postural HTN

Tamsulosin

• selective α_1A

• inferior CV outcomes

• TU: HTN, glucose metabolism, BPH tx

Prazosin

• decreased BP w/ vasodilators

• TU: HTN *not alone

Doxazosin

• decreased BP with vasodilators

• TU: HTN *not alone

• AE: inhibits ejaculation, floppy iris

Yohimbine

• selective α₂ blocker

• increased SNS outflow

• E.D. supplement

Reserpine

• affect NT uptake/release

• depletes NE/dopamine/serotonin

• replaced by better HTN tx

Rest & Digest

• Reduced HR

Rest & Digest

• Elevated airway resistance (bronchoconstriction)

Rest & Digest

• Slowed conduction (decreased HR)

Rest & Digest

• TPR reduced

Rest & Digest

• Decreased BP

Rest & Digest

• Impaired SNS reflexes

Rest & Digest

• GI motility

Rest & Digest

• Erectile dysfunction

Rest & Digest

• Sedation (decreased anxiety)

Rest & Digest

• Tiredness/fatigue

β blockers (non-selective)

• equal β₁ and β₂ activity

Propranolol

• TU: HNT, MI, angina, migraines, hyperthyroidism

• AE: bronchoconstriction, sexual impairment, arrhythmias, metabolic disturbance, CNS

Nadolol

• long DOA

• TU: HTN, angina

Timolol

• DOA: 12-24 hours

• TU: occasionally HTN, glaucoma tx

Carteolol

• DOA: 12-24 hours

• TU: glaucoma tx

• non-selective beta-blocker

Pindolol

• good for bradycardia

• AE: decreases BP

• NOT a pure antagonist

β₁ cardioselective

• TU: HTN, stable angina

Betaxolol

• DOA: 12-24 hours

• TU: glaucoma tx

• selective beta-1 blocker

Acebutolol

• good for bradycardia

• AE: insomnia

• NOT a pure antagonist

Bisoprolol

• TU: chronic heart failure

• cardioselective beta-1 blocker

Esmolol

• short ½ life

• IV administration during procedures

Metoprolol

• TU: chronic heart failure patients

• better for patients with asthma

Atenolol

• TU: decreased BP

• better for patients with asthma

Nebivolol

• released nitric oxide

• vasodilation

non-selective with α₁

• α₁ block causes orthostatic HOTN, dizziness

• decreased peripheral vasoconstriction

Carvedilol

• TU: chronic heart failure patients

• alpha-1 blocker → vasodilation

Labetalol

• HTN in pregnancy (methyldopa alternative)

• IV during HTN emergency