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Flashcards in Adrenergic Drugs Deck (44):

_____ drugs modulate adrenergic transmission and primarily control the fx of the sympathetic nervous system.

____ activate adrenergic transmission by promoting the effects of norepinephrine/epinephrine/dopamine at adrenergic receptors in the sympathetic NS.

____ drugs inhibit adrenergic transmission and prevent the effects or NE/E/Dopamine at adrenergic receptors in the sympathetic NS.





Direct acting adrenergic drugs produce their effects via ____ with adrenergic receptors.

Indirect acting adrenergic drugs produce their effects by ____ the concentration of NE at target receptors. They alter neurotransmitter concentrations at target site.

Direct action

Increasing or reducing


Where are alpha1 receptors located and what is their action?

Vascular smooth m: contraction

Pupillary dilator m: contraction/dilates pupil

Prostate: contraction

Heart: contracton


Where are alpha 2 receptors located and what is their action?

Postsynaptic CNS neurons: many actions

Platelets: aggregation

Adrenergic and cholinergic nerve terminals: inhibits transmitter release

Vascular smooth m: contraction

Fat cells: inhibits lipolysis


Where are beta 1 receptors located and what is their action?

Heart: contraction

Juxtaglomerular cells: increases rennin release


Where are beta 2 receptors located and what is their action?

Respiratory, uterine, vascular smooth m: relaxation

Skeletal m: K uptake (hypopolarization)

Liver: glycogenolysis, gluconeogenesis


Where are beta 3 receptors located and what is their action?

Bladder: relaxes detrusor m

Fat cells: activates lipolysis


Where are dopamine 1 and dopamine 2 receptors located and what is their action?

D1= smooth m: dilates renal blood vessels

D2= nerve endings: modulates transmitter release


What are the types and subtypes of adrenergic receptors?

What are their signal transduction pathways?

Alpha 1: a1A, a1B, a1D -> Gq -> phospholipase C -> release IP3/DAG -> release Ca/protein kinase C

Alpha 2: a2A, a2B, a2C -> Gi -> inhibit adenylyl cyclase -> decrease in cAMP

Beta: B1, B2, B3 -> Gs -> adenylyl cyclase -> increase in cAMP

Dopamine: D1, D2, D3, D4, D5 -> Gs, Gi, Gi, Gi, Gs (Gs=increase cAMP; Gi=decrease cAMP)


List the four types of direct acting adrenergic drugs and what specific drugs belong in each class.

Also list their selectivity at adrenergic receptor subtypes

Alpha: phenylephrine (a1), clonidine (a2)

Mixed alpha and beta: NE (a1/a2/B1), E (a1/a2/B1/B2)

Beta: dobutamine (B1), isoproterenol. (B1/B2), terbutaline (B2), albuterol (B2)

Dopamine: dopamine (D1), fenoldopam (D1)


List the four MOA of indirect acting adrenergic drugs and what specific drugs belong in each class.

Inhibits re-uptake of DA and NE: cocaine

Inhibit monoamine oxidase (MAO): selegiline, phenelzine

Reverse NE and DA uptake mechanisms and increase their release: amphetamines, methylphenidate, tyramine

Releasing agent and direct adrenergic receptor agonist: ephedrine (mixed between direct and indirect)


Epinephrine binds to what receptors in the heart and vessels?

What are their effects?

Alpha1, 2; beta 1,2

B1: increases heart contraction, heart rate, conduction at the AV node

Alpha 1 and B2: increases systolic BP, decrease diastolic BP and total peripheral vascular resistance, mean arterial pressure is unchanged

Alpha1: skin vessels and mucous membranes

Alpha1 and B2: skeletal m

Alpha 1 and D1: renal and cerebral


Epinephrine binds to what receptors in the lungs, skeletal muscle, kidneys, and liver?

What are their effects?

B2: relaxes bronchial m

Alpha 1: decreases bronchial secretion and congestion within bronchial mucosa

B2: muscle tremor, increases K uptake by skeletal m (promotes hypokalemia and decreases K excretion by kidneys)

B2: increases glycogenolysis and gluconeogenesis

B: increases lipolysis

B1: increases renin release


Norepinephrine binds to what receptors?

What are their effects?

Alpha1, alpha 2, beta 1

Reduces HR


Lacks B2 agonist effects therefore no bronchodilation and vasodilation

Increases peripheral vascular resistance and blood pressure



What type of drug is phenylephrine? What are the pharmacodynamic effects?

Alpha adrenergic agonist (a1)

Effective mydriatic and decongestant

Causes severe vasoconstriction, blood pressure elevation, severe bradycardia

Role of baroreflex


What type of drug is clonidine? What are the pharmacodynamic effects?

Alpha 2 adrenergic agonist

Central effect on alpha2 receptors in the lower brainstem area

Decreases sympathetic outflow

Reduction in blood pressure


Local application produces vasoconstriction

Regulation of NE release by presynaptic alpha2 adrenoceptors


What type of drug is isoproterenol? What are the pharmacodynamic effects?

Non-selective beta adrenergic agonist (B1, B2)

Positive inotropic and chronotropic action, increases cardiac output (B1)

Vasodilator, decreases arterial pressure (B2)

Bronchodilation (B2)


What type of drug is dobutamine? What are the pharmacodynamic effects?

Selective B1 adrenergic agonist with alpha 1 receptor activity

- isomer is an agonist at these receptors
+ isomer is an alpha1 antagonist

Potent inotropic action

Less prominent chronotropic action


What type of drug is terbutaline and albuterol? What are the pharmacodynamic effects?

Selective beta 2 adrenergic agonists

Bronchodilation and relaxation of uterus


What type of drug is dopamine? Where are its receptors? What are the pharmacodynamic effects?

Endogenous catecholamine (D1, D2)

Receptors in renal, cerebral, mesenteric and coronary vessels

Activates presynaptic D2 to suppresses NE release

Activates B1 in heart at higher doses

Stimulates vascular alpha 1 receptor to cause vasoconstriction


Indirect acting adrenomimetics include ____ and ___. They target monoamine transporters (VMAT) to increase concentration of NE at adrenergic receptors.

Amphetamines and cocaine


Indirect adrenergic agonists can penetrate the ____ and therefore have central effects on the ____.

Name four indirect adrenergic agonists and what they are used for.

BBB; central nervous system

Amphetamine, methamphetamine: stimulant effect on mood and alertness, decrease appetite, drug of abuse

Methylphenidate: children with ADHD, abuse potential

Cocaine: inhibits transmitter reuptake at adrenergic synapses; local anesthetic properties, drug of abuse


What type of drug is ephedrine?


Clinical uses?

Indirect adrenergic agonist

Releases stored catecholamines with some direct action, nonselective

Nasal decongestant, increases BP, stress incontinence in women, mild stimulant


What is the fx of phenelzine and selegiline?

Inhibit MAO, increase NE stores in CNS, antidepressant action


What type of drug is tyramine?

Where is it found?


Indirect adrenergic agonist

Cheese, cured meats, smoked and pickled fish then metabolized by MAO in liver

Releases stored NE from presynaptic adrenergic terminals; leads to increase in BP in pt taking MOA inhibitors


Name the adrenergic agonist used in each scenario:

Hypotensive emergency like hemorrhagic shock, overdose of antihypertensives, CNS depressants

Chronic hypotension

Cardiogenic shock due to a massive acute MI

Heart failure


Emergency therapy for complete AV block and cardiac arrest

NE, phenylephrine


Dopamine, dobutamine

Short term use of dobutamine in acute HF; dopamine in CHF with reduced renal perfusion

Alpha2 agonist for long term; fenoldopam in emergency

Epinephrine, isoproterenol


Name the adrenergic agonist used in each scenario:




Amphetamines, methylphenidate


Phentermine, ephedrine, amphetamines


Name the adrenergic agonist used in each scenario:

Bronchial asthma

Decongestion of mucous membranes

Anaphylaxis with bronchospasm and upper airway congestion, severe hypotension, cardiac depression

Beta2 selective agonists like albuterol and terbutaline

Phenylephrine, ephedrine, pseudoephedrine



Name the adrenergic agonist used in each scenario:

Induction of mydriasis


Suppression of premature labor

Stress urinary incontinence


Alpha2 selective agonists like apraclonidine, brimonidine

Beta2 agonist like terbutaline



What are cardiovascular adverse effects of adrenergic agonists?

Elevation in BP

Increased cardiac work load leading to myocardial ischemia and heart failure

Sinus tachycardia and serious ventricular arrhythmias inducing cardiac death


What are central nervous system adverse effects caused by indirect acting lipophilic adrenergic agonists?


Lack of appetite

Anxiety, restlessness


Convulsions and hemorrhagic stoke (cocaine)


What are non-selective alpha adrenoceptor antagonist drugs?

What are selective alpha adrenoceptor antagonist drugs?

Phentolamine, phenoxybenzamine

Prozosin, terazosin, tamsulosin, doxazosin, alfuzosin, silodosin


___ is a reversible competitive alpha antagonist. It is non-covalent binding, shorter acting, and its effect is antagonized by a high concentration of agonist.

____ is a non-competitive irreversible alpha antagonist. It is covalent binding, longer acting, effect is not antagonized by alpha agonist.




What are the effects of alpha antagonists on the cardiovascular system?

Genitourinary system?


Decreased peripheral vascular resistance and BP, postural hypotension, reflex tachycardia

Relaxation of smooth m in prostate; decreased resistance to the flow of urine

Relaxation of pupillary dilator m (miosis)


What alpha adrenergic antagonist drugs treat pheochromocytoma?

Chronic hypertension (do NOT use alpha blockers)?

Erectile dysfunction?

Benign prostate hyperplasia?

Phentolamine, phenoxybenzamine

Prazosin, terazosin, doxazosin

Phentolamine, nonspecific vasodilator papverine

Treat chronic urinary obstruction with amsulosin, silodosin; also prazosin, doxazosin, terazosin but will cause a more pronounced drop in BP


What are adverse effects of alpha antagonists?

Postural hypotension (antagonism of alpha1 in venous smooth m)


Retention of fluid and salt

Impaired ejaculation

Nasal stuffineess


What are two mixed blockers?

What are four beta 1 and 2 non-selective adrenoceptor blockers?

What are four B1 selective blockers?

Labetalol, carvedilol (B and alpha 1 antagonist)

Propranolol, pindolol, nadolol, penbutolol

Metoprolol, betaxolol, acebutolol, atenolol


What are four antagonist beta blockers?

Partial agonist beta blockers?

Inverse agonist beta blockers?

Atenolol, nadolol, propranolol, betaxolol

Acebutolol, labetalol, penbutolol, pindolol

Carvedilol, metoprolol


Beta blocker with ISA (intrinsic sympathomimetic activity) are ____ at beta adrenergic receptors.

They block sympathetic effects but have sub maximal effects of their own including ____.

They have less risk for _____, increase in _____, and other effects of beta receptor blockers.

Partial agonists

A blunted sympathetic response

Bradycardia, VLDL/HDL


What effects do beta blockers have on the heart?

Blood vessels?

Renin-angiotensin system?

Negative inotropic effect (weaken the force of contraction), negative chronotropic effect (decrease HR), block AV node (slowed atrioventricular conduction and increased PR interval)

Initially rises in peripheral vascular resistance; chronically decreases in PVR

Inhibits renin release


What effects do beta blockers have on the respiratory system?


Metabolic effects?

Increase airway resistance

Reduce production of aqueous humor to reduce intraocular pressure

Inhibit lipolysis; increase VLDL and decrease HDL, reduce HDL cholesterol/LDL cholesterol ratio; inhibit glycogenolysis and gluconeogeneis in liver


How do beta blockers treat hypertension?

Angina pectoris?

Myocardial infarction?

Cardiac arrhythmias?

Antihypertensive effect is delayed; beta blockers and mixed alpha and beta blockers = Lebetalol

Decreases cardiac work load and reduces O2 consumption; reduce the frequency of anginal episodes and improves exercise tolerance

Prolongs the survival = timolol, propranolol, metoprolol

Effective in ventricular and supraventricular arrhythmias, atrial flutter and atrial fibrillation, ventricular ectopic beats


How do beta blockers treat heart failure?



Metoprolol, bisoprolol, carvedilol; contraindicated in acute CHF

Reduces the production of aqueous humor by the ciliary body = timolol, betaxolol



What are the adverse effects of beta blockers on the CNS?



Lipid profile?

Hypoglycemic episodes?

Discontinuation of beta blocker therapy?

Sedation, sleep disturbances, depression

Increases airway resistance, bronchospasm, asthma attack

Decrease HR, cardiac contractility, increase peripheral vascular disease

Increase in VLDL, decrease HDL

Inhibit glucose output by liver

Gradually taper beta blocker dosing to prevent sympathetic hyper-responsiveness and potential toxicity; increased risk in pt with ischemic heart disease