PHARM Chapter 10 - Adrenergic Pharmacology Flashcards by Kirsten Lederer

ME of Alpha-Methyltyrosine

Inhibit tyrosine hydroxylase, the rate-limiting enzyme in the catecholamine biosynthesis pathway

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Uses of Alpha Methyltyrosine

Pheochromocytoma-associated hypertension

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Structural analogue of tyrosine

Alpha-Methyltyrosine

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Pheochromocytoma

Tumor of the enterochromaffin cells of the adrenal medulla that produces norepinephrine and epinephrine

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Inhibitors of Catecholamine Storage

Reserpine, Guanethidine, Guanadrel, Amphetamine, Methylphenidate, Pseudoephedrine

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ME of Reserpine, Guanethidine, Guanadrel, Amphetamine, Methylphenidate, Pseudoephedrine

Inhibitors of catecholamine storage in vesicles - results in short-term increase in release of catecholamines from the synaptic terminal but long term depletion of available pool of catecholamines

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Uses of Reserpine

Hypertension

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Uses of Guanethidine and Guanadrel

Hypertension

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Uses of Amphetamine and Methylphenidate

ADHD

Narcolepsy (Amphetamine)

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Uses of Pseudoephedrine

Allergic rhinitis

Nasal Congestion

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Irreversibly inhibits VMAT - results in vesicles that lose the ability to concentrate and store norepinephrine and dopamine

Reserpine

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Used experimentally to assess whether effect of drug requires its concentration in presynaptic terminals

Reserpine

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Low vs. High Dose of Reserpine

Low: causes neurotransmitter leak into cytoplasm where catecholamine is destroyed by MAO

High: rate of transmitter leak can be sufficiently high to overwhelm MAP in presynaptic neuron - has transient sympathetic effect

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Why is Reserpine not used therapeutically?

Associated w/ severe depression

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Concentrates in transmitter vesicles and displaces norepinephrine, leading to gradual depletion of norepinephrine

Guanethidine and guanadrel

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Effect of Guanethidine and Guanadrel on Cardiac sympathetic nerves

Reduced cardiac output

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Effect of Guanethidine and Guanadrel on sympathetic nerves

Leads to symptomatic hypotension following exercise

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How does Guanethidine enter neurons

Actively transported by NET, concentrates in vesicles and displaces norepinephrine

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1) Displace endogenous catecholamines from storage vesicle
2) weakly inhibit MAO
3) block catecholamine reuptake mediated by NET and DAT

Amphetamine and Methylpenidate

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Carries risk of dependence and tolerance

Amphetamine and Methylpenidate

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Binds to postsynaptic adrenergic receptors, but has little agonist action at alpha or beta adrenoceptors

Amphetamine

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Used as OTC decongestant

Pseudoephedrine

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Ephedrine used for the treatment of

persistent hypotension

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Herbal source of ephedrine

ma huang

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Dietary amine that is ordinarily metabolized by MAO in GI tract and liver

Tyramine

Fermented foods such as red wine and aged cheese possess high concentrations of

Tyramine

In patients taking MAOIs tyramine is absorbed in gut, transported in blood, and taking up sympathetic neurons where it is transported into synaptic vesicles by ____ to cause _____

VMAT acute displacement of vesicular norepinephrine and massive non-veiscular release of norepinephrine from the nerve terminal via reversal of NET

Tyramine is hydroxylated into a metabolite, ____ which is better able to _____

octopamine Be stored at high concentrations in the vesicles

ME of Cocaine

Inhibits voltage-gated sodium channels in excitable cell membranes Inhibits norepinephrine transport (NET)-mediated reuptake of catecholamines - potentiates catecholamine action

Uses of Cocaine

Mucosal and opthalmic local anesthetic, diagnosis of Horner's syndrome pupil

Major side effect of Cocaine

Cariotoxicity and euphoria

ME of Amitriptyline and Imipramine

Inhibit reuptake of 5-Ht and NE from the synaptic cleft by blocking reuptake transporters, causes enhancement of postsynaptic responses Inhibit norepinephrine transporter (NET)-mediated reuptake of catecholamines, potentiating catecholamine action

Uses of Amitriptyline and Imipramine

Depression, Pain syndromes, nocturnal enuresis (imipramine)

Tricyclic antidepressants that affect cardiac sodium channels in a quinidine-like manner, leading to potentially lethal conduction delays

Amitriptyline and Imipramine

Can precipitate mania in patients w/ bipolar disorder

Amitriptyline and imipramine

Monoamine Oxidase (MAO) Inhibitors

``` Phenelzine Iproniazid Tranylcypromine Clorgyline Brofaromine Befloxatone Moclobemide Selegiline ```

``` ME of Phenelzine Iproniazid Tranylcypromine Clorgyline Brofaromine Befloxatone Moclobemide Selegiline ```

Inhibit MAO - increases catecholamine levels by blocking catecholamine degradation Block deamination of monoamines by inhibiting the functional flavin moiety of MAO; increase the 5-HT and NE available in the cytoplasm of presynaptic neurons, which leads to increased uptake and storage of 5-HT and NE in synaptic vesicles and to some constitutive leakage of monoamines into the synaptic cleft

``` Uses of Phenelzine Iproniazid Tranylcypromine Clorgyline Brofaromine Befloxatone Moclobemide Selegiline ```

Depression

A1 adrenergic agonists

Methoxamine Phenylephrine oxymetazoline tetrahydrozoline

ME of A1 adrenergic agonists

selectively activate A1 adrenergic recpetors to increase peripheral vascular resistance

Uses of methoxamine

hypotension and shock

Uses of Phenylephrine, oxymetazoline, tetrahydrozoline

Opthalmic hyperemia nasal congestion hypotension (phenylephrine only)

Which A1 adrenergic agonist has very limited clinical use in treatment of shock

methoxamine

Contraindication of A1 adrenergic agonists

severe hypertension and narrow angle glaucoma (not methoxamine)

SE of phenylephrine, oxymetazoline, tetrahydrozoline

cardiac arrythmia, hypertension

Afrin and Visine are what type of drugs and what do they treat

A1 adrenergic agonists - nasal congestion and opthalmic hyperemia

What is used intravenously in treatment of shock

phenylephrine

alpha-adrenergic antagonists

``` penoxybenzamine phentolamine prazosin terazosin doxazosin tamsulosin yohimbine ```

ME of alpha adrenergic antagnoists

block endogenous catecholamines from binding to A1 and A1 adrenoceptors - causing vasodilation, decreased blood pressure and decreased peripheral resistance

Uses of penoxybenzamine and phentolamine

pheochromocytoma associated hypertension and sweating

Blocks A1 and A2 receptors irreversibly

phenoxybenzamine

reversible, nonselective alpha-adrenoceptor antagnoist

phentolamine

SE of phentolamine

coronary artery disease

Uses of prazosin, terazosin, doxazosin

hypertension, benign prostatic hyperplasia

nonsubtype-selective antagonists of A1 receptors in arterioles and veins

prazosin, terazosin, doxazosin

why do patients have to remain supine w/ first dose of prazosin, terazosin, doxazosin

severe postural hpotension

SE of prazosin, terazosin, doxazosin

pancreatitis, hepatotoxicit, systemic lupus eruthematosus

uses of tamsulosin

benign prostatic hyperplasia

why is tamsulosin different?

subtpe-selective A1a receptor antagonist that has more specificity towards smooth muscle in GU tract - lower incidence of orthostatic hypotension

uses of yohimbine

organic and psychogenic impotence

SE of yohimbine

bronchospasm, nervousness, tremor, anxiety, agitationq

A2-selective antagonist that leads to increased release of norepinephrine, stimulates cardiac B1-receptors and peripheral vascular A1 receptors

yohimbine

What does yohimbine inadvertently release

increased insulin due to blockade of A2 receptors in pancreatic islets

Suffix for B-adrenergic antagonists

olol

ME of B-adrenergic antagonists

block B-adrenergic receptors

block B1 and B2 receptors equally

propranolol, nadolol, timolol

Ocular formation used in the treatment of glucagoma

timolol, levobunolol, carteolol

Uses of propranolol, nadolol, timolol, prenbutolol, levobunolol, careolol

hypertension, angina, heart failure, phenocrhromocytoma

SE of propranolol, nadolol, timolol, prenbutolol, levobunolol, careolol

bronchospasm AV block, bradyarrythmia

Uses of labetalol, carvedilol, pindolol, acebutolol

hypertension, angina

what additional sideeffect does labetalol have

hepatotoxicity

block A1, B1, and B2 receptors

labetalol and carvedilol

partial agonist at B1 and B2 receptors, preferred in hypertensive patients who have bradycardia or decreased cardiac reeserve

pindolol

partial agonist at B1 adrenoceptors, no effect on B2 receptors

acebutolol

Uses for esmolol, metoprolol, atenolol, betaxolol, nebivolol

hypertension, angina, heart failure, thyroid storm (esmolol)

B1 selective adrenergic antagonists

esmolol, metoprolol, atenolol

extremely short half life (3-4) used for emergency B-blockade

esmolol

has ancillary property of promoting vasodilation via NO release from endothelial cells

nebivolol

MAOI approved for treatment of Parkinsons

selegiline

concomitant use of MAOIs and SSRIs contraindicated because

it can cause serotonin syndrome

A2 receptor agonist that lowers blood pressure by acting in brainstem vasomotor centers to suppress sympathetic flow

clonidine

A2 receptor that can cause sedation and respiratory depression

dexmedetomidine

endogenous enzymes catalyze its metabolism which is then released by adrenergic nerve terinal which it acts presynaptically as A2 antagonist

a-Methyldopa

antihypertensive drug in pregnancy

a-methyldopa

diastolic bp is a __ effect, whereas systolic bp is a __ effect

B2, B1

used intravenously for heart failure and as diagnostic agent in ischemic heart disease

dobutamine

ME of dobutamine and isoproterenol

increase cAMP by activating G protein coupled adrenergic recpetors, acting at cardiac B1 adrenergic receptors to have positive inotropic, chronotropic, and lusitropic effects

uses of dobutamine

short term treatment of cardiac decompensation secondary to depressed contractility (cardiogenic shock)

overall effect of dobutamine is predominantly on __ and modestly on ___

B1 and B2

uses for isoproterenol

emergency treatment of arrythmias, atropine-resistant hemodynamically significant bradycardia, heart block and shock, bronhospasm

ME of metaproterenol, terbutaline, albuterol/salbutamol

agonists at B-adrenergic receptors on airway smooth muscle, act through stimulatory G protein to cause relaxation and bronchodilation

Uses of metaproterenol, terbutaline, albuterol/salbutamol

asthma/copd

Selective agonists at B2 receptors

metaproterneol, terbutaline, albuterol/salbutamol

PHARM Chapter 10 - Adrenergic Pharmacology Flashcards

(93 cards)