Exam #02 - Adrenergic Agonists and Antagonists and Anti-hypertensive Agents Flashcards by mike ferenz

Phenylephrine

Type: Direct-acting Adrenergic agonist

Selectivity: Alpha-1 selective

MOA:
powerful post-synaptic alpha-receptor agonist producing vasoconstriction

Major Therapeutic Use:
nasal decongestant
ophthalmic solutions for mydriasis

AE:
high doses can cause hypertensive HA and heart irregularities

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Clonidine

Brand Name: Catapres

Type: Direct-acting Adrenergic agonist

Selectivity: Alpha-2 selective

Major Therapeutic Use:
hypertension

MOA: stimulates alpha-2 adrenergic receptors in the brain resulting in reduced sympathetic outflow from the CNS and decreased peripheral resistance, renal vascular resistance, HR, and BP

Notes:
2 similar drugs: Guanabenz & Guanfacine

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Dobutamine

Type: Direct-acting Adrenergic agonist

Selectivity: Beta-1 selective

MOA:
stimulates beta-1 receptors in heart

Major Therapeutic Use:
increase CO and cardiac contractility to treat CHF

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Terbutaline

Type: Direct-acting Adrenergic agonist
Selectivity: Beta-2 selective

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Isoproterenol

Type: Direct-acting Adrenergic agonist

Selectivity: Non-selective Beta agonist

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Epinephrine

Type: Direct-acting Adrenergic agonist

Selectivity: Non-selective agonist

MOA:
activates both alpha and beta receptors

Major Therapeutic Use:
anaphylaxis, asthma, cardiac arrest, glaucoma,
cardiac stimulant (inotropic & chronotropic), potent vasoconstrictor, increase duration of LA for nerve block (give LA with epi constricts adjacent vessels and forms pocket), control of local bleeding (esp for facial surgery)

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Type: Direct-acting Adrenergic agonist

Selectivity: Non-selective agonist (hits all but beta-2)

MOA:
a sympathomimetic amine alpha activity results in peripheral vasoconstriction and beta activity leading to inotropic stimulation of the heart and coronary artery vasodilation

Major Therapeutic Use:
hypotension
cardiac arrest

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Ephedrine

Type: Indirect/Mixed adrenergic agonist

Selectivity: Non-selective agonist

MOA: releases stored catecholamines (namely NE) increasing activity on adrenergic receptors

Major Therapeutic Use:
nasal decongestant, weight loss products

Notes:
found in Ma Huang plant
can cross BBB

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Amphetamine

Type: Indirect Adrenergic agonist

MOA: stimulates release of NE, DA, and serotonin by impairing VMAT - more DA gets released into cytosol and gets pushed out into the synapse (some gets metabolized in cytoplasm before it’s released)
appetite suppressant and CNS stimulant

Major Therapeutic Use:
derivatives of amphetamine are used to treat ADHD and narcolepsy

AE:
toxicity due to excess beta receptor stimulation of the heart

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Tyramine

Type: Indirect Adrenergic agonist

MOA:
stimulates the release of catecholamine (namely NE)

AE:
Tyramine is found in fermented foods (cheese, sausage, pickled fish, wine). If patient ingests these foods and is also taking a MAO inhibitor, there will be an increase in [NE] which can lead to a hypertensive crisis

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Cocaine

Type: Indirect-acting Adrenergic agonist

Therapeutic Use: LA, vasoconstriction, peripheral sympathomimetic actions

MOA: inhibits reuptake of NE, DA, and serotonin by working at the DAT and NET

AE:
toxicity due to beta-receptor stimulation of heart
abuse mainly related to inhibition of DA reuptake

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Reserpine

MOA: Irreversibly binds to VMAT stopping the packing of NE and DA into vesicles. Reduces sympathetic output, decreases HR and arterial BP

Major Therapeutic Use:
hypertension
psychotic disorder

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Would direct acting adrenergic agonists be impacted by prior treatment with reserpine?

No, responses may actually be potentiated by reserpine (and cocaine)

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Would mixed acting adrenergic agonists be impacted by prior treatment with reserpine?

Yes, b/c ephedrine is still acting on post-synaptic receptors, the response would be reduced

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Would indirect acting adrenergic agonists be impacted by prior treatment with reserpine?

Yes, responses are abolished b/c stores of NE and DA have been depleted

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Dopamine (DA)

Brand Name: Intropin

Selectivity: dopaminergic and adrenergic agonist

MOA:
produces positive inotropic and chronotropic effects on myocardium by activating beta1-receptors on heart and releases NE from storage sites thus increasing heart rate and contractility. Also stimulates alpha-adrenoreceptor activity resulting in vasoconstriction increasing peripheral resistance and a rise in BP

Major Therapeutic Use:
raises BP (vasopressor)
useful in treating CHF
at low doses, good for treating shock situations

Notes: Dose dependent; at low doses PR can decrease, at higher doses activates alpha-1 receptors leading to vasoconstriction

Salmeterol

Formoterol (Foradil)

Brand name: Serevent

Selectivity: beta-2 agonist

MOA:
activation of beta-2 receptors in lungs
long acting due to high lipid solubility

Major Therapeutic Use:
Chronic asthma and COPD
DOC for long lasting effects
Used as asthma prophylaxis

AE: tremor, tachycardia (from effects way down the line on beta-1 receptor)

Albuterol

Metaproterenol

Pirbuterol (Maxair)

Brand name: Proventil

Selectivity: beta-2 agonist

MOA:
activation of beta-2 receptors in lungs
max effects within 15-30 min, lasts 3-4 hours

Major Therapeutic Use:
acute bronchospasm
useful in treating exercise induced asthma

AE:
use with caution in patients with cardiac arrythmias and uncontrolled hypertension
tremor, tachycardia

Pseudoephedrine

Type: Indirect/Mixed adrenergic agonist

Selectivity: Non-selective agonist

MOA: releases stored catecholamines (namely NE) increasing activity on adrenergic receptors

Major Therapeutic Use:
OTC nasal/sinus decongestant

Notes:
found in Ma Huang plant
can cross BBB

Phentolamine

Type: non-selective alpha antagonist (competitive, surmountable)

MOA:
Reversibly binds and blocks alpha-1 and alpha-2 receptors. Decreases peripheral resistance (alpha-1) and increase CO (blocking alpha-2 receptors increase sympathetic outflow)

Major Therapeutic Use:
pheochromocytoma (tumor in adrenal medulla releasing excess Epi and NE)
shorter duration of action than Phenoxybenzamine

AE:
postural hypotension
tachycardia

Phenoxybenzamine

Type: non-selective alpha antagonist (non-competitive, non-surmountable)

MOA: irreversibly binds and blocks alpha-1 and alpha-2 receptors. Decreases peripheral resistance (alpha-1) and increase CO (blocking alpha-2 receptors increase sympathetic outflow)

Major Therapeutic Use:
pheochromocytoma (tumor in adrenal medulla releasing excess Epi and NE)
long duration of action

AE:
postural hypotension
tachycardia

Prazosin
&
Terazosin
&
Doxazosin

Type: alpha-1 selective antagonist

MOA:
blocks alpha-1 receptors which decreases peripheral resistance

Major Therapeutic Use:
moderate to mild hypertension
BPH

AE:
vertigo
reflex tachycardia
postural hypotension

Tamsulosin

Type: alpha-1 selective antagonist (selective for receptors in prostate)

MOA:
blocks alpha-1 receptors (mostly) in prostate

Major Therapeutic Use:
only used to treat BPH since it’s very selective for alpha-1 receptors in the prostate

Yohimbine

Type: alpha-2 selective antagonist

No present clinical role

Propanolol

Type: non-selective beta blocker MOA: blocks beta-1 and beta-2 receptors, decreasing HR, myocardial contractility, BP, and O2 demand (from heart slowing down) ``` Major Therapeutic Use: hypertension angina arrythmias and tachycardia migraine prophylaxis ``` AE: use with caution in asthma patients, since this is a non-selective beta blocker (blocking beta-2 receptor would result in increased bronchoconstriction

``` Acebutolol & Atenolol & Metoprolol ```

Type: Beta-1 selective blocker (competitive, surmountable) MOA: blocks beta-1 receptors resulting in decreased HR, CO, BP Major Therapeutic Use: hypertension (especially in patients with asthma) supraventricular and ventricular arrythmias ischemic heart disease

Esmolol

Type: Beta-1 selective blocker (competitive, surmountable) MOA: blocks beta-1 receptors resulting in decreased HR, CO, BP. rapid onset, short acting drug (10 min) Major Therapeutic Use: Useful in treating critically ill patients with arrhythmias via IV in hospital setting only.

Timolol

Type: non-selective beta blocker Major Therapeutic Use: treats open angle glaucoma NO LA effect so safe for glaucoma (you wouldn't want to numb the eye to treat glaucoma)

Nadolol

Type: non-selective beta blocker Major Therapeutic Use: hypertension LONG ACTING (14-24 hours)

Labetalol

Type: non-selective alpha & beta blocker Major Therapeutic Use: hypertension heart failure arrythmias, angina AE: use caution in asthma patients Notes: NOT useful in treating glaucoma b/c it has LA effect

Carvedilol

Type: non-selective alpha & beta blocker MOA: non-selective blocker, plus Ca+2 channel blocker, antioxidant activity Major Therapeutic Use: useful in treating patients with CHF b/c it's slightly more beta selective hypertension AE: use caution in asthma patients Note: metabolite of carvedilol has amazing anti-oxidant properties

Nebivolol

Type: beta-1 selective blocker MOA: blocks beta-1 receptors AND increases NO production (contributes to vasodilation) Long acting (11-30 hours) Major Therapeutic Use: hypertension

Carteolol

Type: non-selective beta blocker MOA: blocks beta-1 receptors AND increases NO production AND has partial agonism on beta-2 receptors (all contributing to vasodilation) Major Therapeutic Use: hypertension

Betaxolol

Type: beta-1 selective blocker MOA: blocks beta-1 receptors AND Ca+2 channel blocker (contributes to vasodilation) Major Therapeutic Use: hypertension glaucoma

Methyldopa

Type: alpha-2 selective agonist MOA: methyldopa injected, rapidly enters brain, converted into methylnorepinephrine which activates alpha-2 receptors and leads to reduction in sympathetic outflow lowering CO, peripheral resistance, and BP Major Therapeutic Use: hypertension in pregnant women Notes: much longer duration of action compared to Clonidine (the other alpha-2 agonist)