Adrenoreceptor Antagonist Drugs

BPH

benign prostatic hypertrophy

DAT

dopamine transporter

NET

norepinephrine transporter

PACG

primary angle closure glaucoma

POAG

primary open angle glaucoma

5HT

serotonin

SERT

serotonin transporter

Alpha 1, alpha 2 receptor primary impact site

CNS and periphery

Alpha 1, alpha 2 receptor clinical conditions

pheochromocytoma, HTN, BPH

Beta 1, beta 2, beta 3 receptor primary impact site

periphery primarily

Beta 1, beta 2, beta 3 receptor clinical conditions

HTN, CVD, arrhythmias, endocrine and neurological disorders, glaucoma

Dopa 1-5 receptor primary impact site

CNS primarily

Dopa 1-5 receptor clinical conditions

psychiatric disorders

Tamsulosin is typically only used in male populations but may be used in females with ___

kidney stones

Alpha antagonists, like Prazosin, Terazosin, and Doxazosin, have a higher selectivity for

Alpha 1 > > alpha 2 receptors

Difference between metoprolol succinate and metoprolol tartrate

Tartrate is not extended release, likely have to take more than once a day; succinate is ER

Mixed alpha/beta antagonists, like Labetalol and Carvedilol, have a higher selectivity for

Beta 1 = Beta 2 >/= alpha 1 > alpha 2

Beta antagonists, like Metoprolol and Atenolol, have a higher selectivity for

beta 1 > > beta 2 receptors

Beta antagonists, like Propranolol, have a

equal selectivity for beta 1 and beta 2 receptors

Prazosin [Minipres] MOA

competitively blocks alpha 1 receptors

Prazosin [Minipres] indications

HTN, BPH

Tamsulosin [Flomax] MOA

competitively blocks alpha 1A and alpha 1D receptors

Tamsulosin [Flomax] indications

BPH

Labetolol [Normodyne] MOA

beta > alpha 1 receptor blocking

Labetolol [Normodyne] indications

HTN

Carvedilol [Coreg] MOA

beta > alpha 1 receptor blocking

Carvedilol [Coreg] indications

HF

Generally, most of our beta receptor antagonist drugs are competitive antagonists, however _____ has inverse agonist activity at beta 1 receptor

metoprolol

Beta receptor antagonist can have

b1 or b2 receptor selectivity

Receptor selectivity is ___

dose-related and diminishes at high doses

Clinical use of beta blockers can be influenced by

lipophilicity (ex. propranolol has high lipophilicity = CNS impact)

Propranolol and metoprolol are extensively

hepatically metabolized

We should be selective in using b2 antagonists in patients with

potential bronchospasm from asthma

Atenolol [Tenormin] selectivity, partial agonist activity, and lipid solubility

selectivity = B1

no partial agonist activity

low lipid solubility

Carvedilol [Coreg] selectivity, partial agonist activity, and lipid solubility

non-selective

no partial agonist activity

moderate lipid solubility

Labetalol [Normodyne] selectivity, partial agonist activity, and lipid solubility

non-selective

yes partial agonist activity

low lipid solubility

Metoprolol [Lopressor] selectivity, partial agonist activity, and lipid solubility

B1 selectivity

no partial agonist activity

moderate lipid solubility

Propranolol [Inderal] selectivity, partial agonist activity, and lipid solubility

non-selective

no partial agonist activity

high lipid solubility

Drug for HTN

metoprolol (not a primary indication for solo use)

Drug for ischemic heart disease

Propranolol or metoprolol (useful or angina, after MIs, and HF)

Drug for cardiac arrhythmias

Metoprolol (A Fib rate control)

Drug for heart failure

Metoprolol or Carvedilol (HFrEF = heart failure w/ reduced ejection fraction)

Drug for glaucoma

Betaxolol or Timolol (reduce formation of aqueous humor)

Drug for hyperthyroidism

propranolol (control heart rate)

Drug for migraine headache, anxiety

Propranolol, metoprolol, atenolol (headache prophylaxis)

Excessive beta receptor blocking can result in

excessive beta blockade impact

Excessive beta blockade impact signs

bradycardia

CNS impacts = sedation, depression, vivid dreams

bronchoconstriction (asthmatic patients)

patients with severe peripheral vascular disease

depression of myocardial contractility, excitability

may also obscure early signs of hypoglycemia

Rapid discontinuation of beta blockers may cause

rebound cardiac symptoms

Phentolamine [Oraverse] class

Alpha 1 and 2 adrenoreceptor antagonist

Phentolamine [Oraverse] indications

extravasation of norepinephrine, hypertensive crisis

Phentolamine [Oraverse] MOA simplified

binds to alpha receptors usually activated by norepinephrine and epinephrine and blocks the binding of those hormones

by blocking the binding = lowers blood pressure (epi and norepi usually increase BP)

also decreases tissue damage by blocking other hormones that can leak out and cause damage = why extravasation is an indication

Prazosin [Minipress] class

alpha 1 adrenoreceptor antagonist

Prazosin [Minipress] indications

HTN (not first line therapy)

Prazosin [Minipress] MOA

competitively inhibits post-synaptic alpha 1 receptors on blood vessels

result = veins and arteries relax and widen, decrease both peripheral resistance and blood pressure

(d/t blockage of epilepsy and norepi binding at these receptors)

Tamsulosin [Flomax] class

alpha 1 adrenoreceptor antagonist

Tamsulosin [Flomax] indications

Benign prostatic hyperplasia (BGH)

Tamsulosin [Flomax] MOA

blocks alpha 1a receptors in prostate and bladder

causes muscles to relax, making it easier to urinate (blocks epi/norepi binding = inhibits sympathetic response in that area)

Propranolol [Inderal] class

beta 1 and beta 2 adrenoreceptor antagonist, non-selective

Propranolol [Inderal] indications

angina, cardiac arrhythmias, HTN, migraine headache prevention, MI, pheochromocytoma, hypertrophic cardiomyopathy; off label for performance anxiety disorder

Propranolol [Inderal] MOA

blocks both beta 1 and beta 2 receptors (non-selective)

result = slows down the heart and narrows blood vessels in the gut area (splanchnic vasoconstriction), which helps lower pressure in the portal vein (the vein going to the liver)

Metoprolol Tartrate/Succinate [Lopressor/Toprol XL] class

beta 1 > beta 2 selective adrenergic antagonist

Metoprolol Tartrate/Succinate [Lopressor/Toprol XL] indications

HFrEF, HTN, post MI

Metoprolol Tartrate/Succinate [Lopressor/Toprol XL] MOA

drug selectively blocks beta-1 receptors, which mostly affects the heart, and has little to no effect on beta-2 receptors(like those in the lungs) when taken at doses under 100 mg
At doses over 100 mg, it can also start to block beta-2 receptors

Carvedilol [Coreg] class

beta 1, beta 2 > alpha 1 adrenergic antagonist

Carvedilol [Coreg] indications

HFrEF, HTN; post MI left ventricular dysfunction

Carvedilol [Coreg]

drug blocks both beta receptors (beta-1 and beta-2) and alpha receptors, which means it affects the heart, blood vessels, and lungs, helping to lower blood pressure and heart rate by relaxing blood vessels and reducing stress signals

Betaxolol [Betapoic S] class

beta 1 adrenergic antagonist, topical

Betaxolol [Betapoic S] indications

treatment of elevated intraocular pressure in patients with chronic open-angle glaucoma

Betaxolol [Betapoic S] MOA

competitively blocks beta1 receptors, with little or no effect on beta 2 receptors

Metryosine [Demser] class

tyrosine hydroxylase inhibitor

Metryosine [Demser] indications

pheochromocytoma

Metryosine [Demser] MOA

blocks the rate-limiting step in the biosynthetic pathway of catecholamines reducing their biosynthesis by 35% to 80%