127 Questions
What is the main mechanism of action for direct adrenergic agonists?
Work on receptor binding
Which of the following is NOT a major catecholamine?
Ephedrine
What property do all catecholamines share due to their chemistry?
Brief duration of action
What is the name of the enzymes that quickly metabolize catecholamines?
Catechol-O-methyltransferase [COMT]
What distinguishes indirect adrenergic agonists from direct ones?
They promote norepinephrine release
Which class of adrenergic agonists is named after its structural components?
Catecholamines
Why can't catecholamines be used orally?
They cannot cross the blood-brain barrier
Which enzyme is responsible for the degradation of noncatecholamines and metabolizes them slowly?
MAO
Why are catecholamine-containing solutions discarded when they turn pink or brown?
Due to oxidation of the catecholamine molecule
What makes noncatecholamines considerably less polar than catecholamines?
Presence of a catechol group
Why are catecholamines ineffective when given orally?
They rapidly degrade by MAO and COMT
What causes the pink or brown discoloration of catecholamine-containing solutions over time?
Oxidation of the catecholamine molecule
How do noncatecholamines differ from catecholamines in terms of reaching systemic circulation when given orally?
Noncatecholamines can reach systemic circulation more effectively
What allows noncatecholamines to cross the blood brain barrier more easily?
Considerably less polar nature
What is the receptor specificity of albuterol?
B2 receptors only
At what dose does the selectivity of albuterol decline?
High doses
What are the two responses elicited by activation of A1 receptors?
Vasoconstriction and mydriasis
What are the therapeutic applications of activation of A1 receptors?
Hemostasis and nasal decongestion
What causes the adverse effects of alpha-1 receptor activation?
Vasoconstriction
What is the clinical significance of alpha-2 receptor activation in the central nervous system?
Inhibits NE release
What is the main therapeutic use of activation of alpha-2 receptors in the central nervous system?
Sedation
What determines the ability of a drug to selectively activate certain receptors?
Dosage level
Which effect is associated with the activation of beta-1 receptors in the heart?
Increase in heart rate
What is a potential risk for patients with compromised coronary circulation when exposed to beta-1 agonists?
Increased risk for angina
Which therapeutic application is associated with B2 receptors in the body?
Relaxation of uterine smooth muscle
What adverse effect is specifically seen in diabetics due to the activation of B2 receptors?
Hyperglycemia
What is the main effect of B1 agonists in terms of cardiac O2 demand?
Increase in cardiac O2 demand
Which condition is NOT a therapeutic application of B2 receptors?
Shock
What is a potential adverse effect of B2 receptor activation in non-diabetic individuals?
Tachycardia
Which effect is associated with the activation of B1 receptors in the kidneys?
No untoward effects
What is the receptor specificity of dopamine at high doses?
A1
Which adrenergic agonist is indicated for the treatment of heart failure?
Dobutamine
What is the receptor specificity of phenylephrine?
A1 receptors
What is the specific therapeutic application of albuterol?
Asthma
What is the main adverse effect associated with ephedrine's activation of alpha and beta receptors?
Hypertension
At what doses does albuterol activate B1 receptors?
High doses
What is the main adverse effect of dobutamine?
Tachycardia
4
A1 receptors
What type of drug is phenylephrine?
Noncatecholamine
What is the specific therapeutic application of dopamine?
Shock
What adverse effect can be caused by albuterol at high doses?
Tremor
What is the receptor specificity of dopamine?
Alpha-1, alpha-2, and beta-1
What is the main therapeutic use of norepinephrine?
Hypotensive states
Which adverse effect is specifically associated with the use of epinephrine?
Local necrosis on extravasation
What is the receptor specificity of isoproterenol?
Beta-1 and beta-2
What are the therapeutic uses of epinephrine?
All of the above
Which enzyme is responsible for metabolizing epinephrine?
MAO and COMT
What is the adverse effect associated with norepinephrine?
Angina
What is the primary mechanism of action for adrenergic antagonists?
Reversible competitive blockade of adrenergic receptors
How do adrenergic antagonists lower arterial pressure?
By dilating veins to indirectly reduce arterial pressure
In what condition can an alpha adrenergic antagonist be used to prevent injury?
Extravasated necrosis due to local vasoconstriction
What is the therapeutic application of alpha blockade in BPH?
To treat the proliferation of the prostate gland
What is the primary effect of overdose with an alpha-adrenergic agonist?
Hypertension due to excessive activation of A1 receptors on blood vessels
What is the main therapeutic application of reversible competitive blockade?
Treatment of essential hypertension
What is the specific therapeutic application of alpha blockade in Raynaud Disease?
Treatment of local vasoconstriction and prevention of injury
In what condition does an alpha adrenergic antagonist cause the reduction of arterial pressure by indirect process?
Extravasated necrosis due to intense local vasoconstriction
What is the direct effect of dilation of arterioles caused by adrenergic antagonists?
Reduction in cardiac output and arterial pressure
What is the primary action of adrenergic antagonists when used for reversal of toxicity from alpha agonists?
Blocking the excessive vasoconstriction caused by the alpha agonist
What differentiates most adrenergic antagonists from adrenergic agonists?
They are more selective than adrenergic agonists
What is the primary symptom of Raynaud's disease?
Discoloration due to decreased circulation in toes and fingers
Why is orthostatic hypotension a significant adverse effect of alpha-1 receptor blockade?
It is secondary to blockade of alpha receptors on veins, reducing muscle tone in the venous wall
Which group of alpha adrenergic blocking agents produces selective A1 blockade?
Prazosin
What is the most significant adverse effect associated with alpha-2 receptor blockade?
Potentiation of reflex tachycardia
Which alpha adrenergic blocking agent can cause abnormal ejaculation and has an increased risk for rhinitis?
Tamsulosin
What is the primary use of prazosin among the 'zosins' group of drugs?
Treatment of hypertension
What is the specific reason for giving alpha-1 antagonists prior to surgery for pheochromocytoma?
To avoid manipulation of the tumor causing massive catecholamine release
Why is impotence reversible once alpha-1 antagonist drug is discontinued?
'First-dose' effect leads to reversible impotence
Which peripheral vascular disorder can be suppressed by preventing alpha-mediated base vasoconstriction?
Raynaud's disease
What is the major reason for using alpha-1 antagonists long term if the pheochromocytoma tumor is inoperable?
To treat hypertension resulting from tumor activity
What adverse effect results from sodium retention and increased blood volume due to reduced blood pressure caused by alpha-1 blockade?
Orthostatic hypotension
What distinguishes prazosin from alfuzosin among the 'zosins' group of drugs?
Alfuzosin can prolong QT and should not be given with inhibitors of CYP34A, while prazosin does not have these effects.
What is the main therapeutic application of phentolamine?
Treatment of pheochromocytoma
How do beta adrenergic blockers prevent ischemia and pain?
By reducing oxygen demand and balancing it with oxygen supply
What is a common long-term effect of beta adrenergic antagonist use on peripheral vascular resistance?
Decreased peripheral vascular resistance
What is the main therapeutic application of beta adrenergic blockers in antianginal therapy?
Reducing oxygen demand
What is the primary use of beta adrenergic antagonists in treating dysrhythmias?
Reducing electrical activity in the sinus node and atria
What is the long-lasting effect of phenoxybenzamine receptor blockade?
Irreversible receptor blockade
What are the approved applications of phentolamine?
Diagnosis and treatment of pheochromocytoma, prevention of tissue necrosis, reversal of soft tissue anesthesia
What is the primary effect of beta adrenergic antagonists on cardiac workload?
Decreasing cardiac workload
What are the adverse effects associated with phentolamine?
Orthostatic hypotension and reflex tachycardia
What are the approved applications of phenoxybenzamine?
Diagnosis and treatment of pheochromocytoma, prevention of tissue necrosis
Which adverse effect can be caused by the activation of B2 receptors in the lung?
Bronchoconstriction
What is the primary therapeutic use of propranolol?
Prevention of migraine
What is the effect of blocking B1 receptors in the heart by propranolol?
Decreased cardiac output
Which adverse effect is specifically associated with the use of metoprolol?
Bradycardia
What is the primary reason for using a B1 selective agent in patients with asthma who need a beta blocker?
To prevent bronchoconstriction
What is the mechanism by which propranolol reduces the force of ventricular contraction?
Suppression of impulse conduction through the AV node
What is the primary reason for minimizing the risk of rebound excitation when withdrawing beta blockers?
To prevent anginal pain or ventricular dysrhythmias
What is the primary effect of metoprolol on heart rate?
Decreased heart rate
What is the most significant adverse effect observed with Betaxolol and other beta blockers?
Bradycardia
What is the primary reason for using a B1 selective agent in patients with diabetes mellitus who need a beta blocker?
To avoid hypoglycemia
How do beta blockers contribute to the treatment of an MI?
They reduce the pain
What is the mechanism by which beta blockers prevent tachydysrhythmia and angina in hyperthyroidism?
By normalizing the levels of sympathetic activity to the heart
What is one of the therapeutic applications of beta blockers?
Stage fright
What is a potential risk associated with using beta blockers in patients with heart failure or reduced cardiac reserve?
Insufficient tissue perfusion
Why should beta blockers be discontinued in patients with stage D heart failure?
They exacerbate heart failure symptoms
What is AV heart block defined as?
A delay in atrial impulse conduction through the AV node
What effect do non-selective beta adrenergic blocking agents produce compared to cardioselective beta-adrenergic antagonists?
Broader spectrum of adverse effects
What is a specific therapeutic use of non-selective beta blockade?
Treatment of glaucoma
What is one of the adverse effects of Beta1 blockade?
Suppression of cardiac function
What adverse effect can beta blockers precipitate in some patients?
Heart failure
Which beta blockers have high solubility and primarily penetrate the blood-brain barrier?
Propranolol, Metoprolol
What is the only approved indication for esmolol?
Emergency IV therapy of SVT
Which beta blocker can cause postural hypotension?
Carvedilol
Which beta blockers have a black box warning for abrupt discontinuation and increased risk for angina and MI?
Atenolol, Metoprolol
Which type of adrenergic blocking drugs are used primarily for hypertension?
Indirect-acting antiadrenergic agents
What is the main difference between labetalol, carvedilol, and nebivolol from other beta blockers?
They primarily block alpha adrenergic receptors
What makes sotalol and esmolol unsuitable for treating hypertension?
They require maintenance of blood levels throughout the day
What is the effect of activating A2 receptors located on presynaptic nerve terminals?
Decreased NE synthesis
What is the main adverse effect associated with carvedilol, labetalol, and nebivolol?
Postural hypotension
Which receptor activation do the indirect-acting antiadrenergic agents prevent by mechanisms not involving direct interaction with peripheral receptors?
A1 receptors
What is the main pharmacological effect of clonidine?
Bradycardia and decrease in cardiac output
Why is clonidine not recommended during pregnancy?
It can have adverse effects on the fetus
What is a common adverse effect of clonidine experienced by 40% of patients?
Xerostomia (dry mouth)
How does clonidine affect sympathetic outflow to the blood vessels and heart?
It reduces sympathetic outflow
What is the route of administration for clonidine in epidural administration?
Solution for epidural administration
In what area of the central nervous system does clonidine selectively activate A2 receptors?
Brainstem associated with autonomic regulation
What is the primary mechanism of clonidine's action in reducing sympathetic outflow?
Selective activation of A2 receptors in the CNS
Which adverse effect is specifically associated with clonidine withdrawal?
Rebound hypertension
What is the primary therapeutic use of guanfacine?
Treatment of hypertension and ADHD
How do guanfacine and clonidine benefit patients with hypertension?
By activating brainstem A2 adrenergic receptors
What distinguishes methyldopate from methyldopa?
Route of administration
What is the only therapeutic use of methyldopa and methyldopate?
Treatment of hypertension
Which organization designated methyldopa as one of the preferred drugs for managing hypertension during pregnancy?
American College of Obstetricians and Gynecologists
What are the adverse effects associated with methyldopa?
Hemolytic anemia and hepatic necrosis
What is the primary reason for designating methyldopa as one of the preferred drugs for managing hypertension during pregnancy?
No fetal harm associated with this medication
What are the other two drugs designated by the American College of Obstetricians and Gynecologists for managing hypertension during pregnancy?
Labetalol and nifedipine
Test your knowledge on the mechanisms and types of adrenergic receptor activation, focusing on direct and indirect agonists such as dopamine, epinephrine, isoproterenol, and ephedrine.
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