Adrenergic Agonists and Receptor Activation
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Questions and Answers

What is the main mechanism of action for direct adrenergic agonists?

  • Inhibition of norepinephrine inactivation
  • Promotion of norepinephrine release
  • Blockade of norepinephrine re uptake
  • Work on receptor binding (correct)

    • Which of the following is NOT a major catecholamine?

  • Norepinephrine
  • Isoproterenol
  • Ephedrine (correct)
  • Dopamine

    • What property do all catecholamines share due to their chemistry?

  • Ability to act in the central nervous system
  • Brief duration of action (correct)
  • Oral use availability
  • Long duration of action

    • What is the name of the enzymes that quickly metabolize catecholamines?

    <p>Catechol-O-methyltransferase [COMT]</p> Signup and view all the answers

    What distinguishes indirect adrenergic agonists from direct ones?

    <p>They promote norepinephrine release</p> Signup and view all the answers

    Which class of adrenergic agonists is named after its structural components?

    <p>Catecholamines</p> Signup and view all the answers

    Why can't catecholamines be used orally?

    <p>They cannot cross the blood-brain barrier</p> Signup and view all the answers

    Which enzyme is responsible for the degradation of noncatecholamines and metabolizes them slowly?

    <p>MAO</p> Signup and view all the answers

    Why are catecholamine-containing solutions discarded when they turn pink or brown?

    <p>Due to oxidation of the catecholamine molecule</p> Signup and view all the answers

    What makes noncatecholamines considerably less polar than catecholamines?

    <p>Presence of a catechol group</p> Signup and view all the answers

    Why are catecholamines ineffective when given orally?

    <p>They rapidly degrade by MAO and COMT</p> Signup and view all the answers

    What causes the pink or brown discoloration of catecholamine-containing solutions over time?

    <p>Oxidation of the catecholamine molecule</p> Signup and view all the answers

    How do noncatecholamines differ from catecholamines in terms of reaching systemic circulation when given orally?

    <p>Noncatecholamines can reach systemic circulation more effectively</p> Signup and view all the answers

    What allows noncatecholamines to cross the blood brain barrier more easily?

    <p>Considerably less polar nature</p> Signup and view all the answers

    What is the receptor specificity of albuterol?

    <p>B2 receptors only</p> Signup and view all the answers

    At what dose does the selectivity of albuterol decline?

    <p>High doses</p> Signup and view all the answers

    What are the two responses elicited by activation of A1 receptors?

    <p>Vasoconstriction and mydriasis</p> Signup and view all the answers

    What are the therapeutic applications of activation of A1 receptors?

    <p>Hemostasis and nasal decongestion</p> Signup and view all the answers

    What causes the adverse effects of alpha-1 receptor activation?

    <p>Vasoconstriction</p> Signup and view all the answers

    What is the clinical significance of alpha-2 receptor activation in the central nervous system?

    <p>Inhibits NE release</p> Signup and view all the answers

    What is the main therapeutic use of activation of alpha-2 receptors in the central nervous system?

    <p>Sedation</p> Signup and view all the answers

    What determines the ability of a drug to selectively activate certain receptors?

    <p>Dosage level</p> Signup and view all the answers

    Which effect is associated with the activation of beta-1 receptors in the heart?

    <p>Increase in heart rate</p> Signup and view all the answers

    What is a potential risk for patients with compromised coronary circulation when exposed to beta-1 agonists?

    <p>Increased risk for angina</p> Signup and view all the answers

    Which therapeutic application is associated with B2 receptors in the body?

    <p>Relaxation of uterine smooth muscle</p> Signup and view all the answers

    What adverse effect is specifically seen in diabetics due to the activation of B2 receptors?

    <p>Hyperglycemia</p> Signup and view all the answers

    What is the main effect of B1 agonists in terms of cardiac O2 demand?

    <p>Increase in cardiac O2 demand</p> Signup and view all the answers

    Which condition is NOT a therapeutic application of B2 receptors?

    <p>Shock</p> Signup and view all the answers

    What is a potential adverse effect of B2 receptor activation in non-diabetic individuals?

    <p>Tachycardia</p> Signup and view all the answers

    Which effect is associated with the activation of B1 receptors in the kidneys?

    <p>No untoward effects</p> Signup and view all the answers

    What is the receptor specificity of dopamine at high doses?

    <p>A1</p> Signup and view all the answers

    Which adrenergic agonist is indicated for the treatment of heart failure?

    <p>Dobutamine</p> Signup and view all the answers

    What is the receptor specificity of phenylephrine?

    <p>A1 receptors</p> Signup and view all the answers

    What is the specific therapeutic application of albuterol?

    <p>Asthma</p> Signup and view all the answers

    What is the main adverse effect associated with ephedrine's activation of alpha and beta receptors?

    <p>Hypertension</p> Signup and view all the answers

    At what doses does albuterol activate B1 receptors?

    <p>High doses</p> Signup and view all the answers

    What is the main adverse effect of dobutamine?

    <p>Tachycardia</p> Signup and view all the answers

    4

    <p>A1 receptors</p> Signup and view all the answers

    What type of drug is phenylephrine?

    <p>Noncatecholamine</p> Signup and view all the answers

    What is the specific therapeutic application of dopamine?

    <p>Shock</p> Signup and view all the answers

    What adverse effect can be caused by albuterol at high doses?

    <p>Tremor</p> Signup and view all the answers

    What is the receptor specificity of dopamine?

    <p>Alpha-1, alpha-2, and beta-1</p> Signup and view all the answers

    What is the main therapeutic use of norepinephrine?

    <p>Hypotensive states</p> Signup and view all the answers

    Which adverse effect is specifically associated with the use of epinephrine?

    <p>Local necrosis on extravasation</p> Signup and view all the answers

    What is the receptor specificity of isoproterenol?

    <p>Beta-1 and beta-2</p> Signup and view all the answers

    What are the therapeutic uses of epinephrine?

    <p>All of the above</p> Signup and view all the answers

    Which enzyme is responsible for metabolizing epinephrine?

    <p>MAO and COMT</p> Signup and view all the answers

    What is the adverse effect associated with norepinephrine?

    <p>Angina</p> Signup and view all the answers

    What is the primary mechanism of action for adrenergic antagonists?

    <p>Reversible competitive blockade of adrenergic receptors</p> Signup and view all the answers

    How do adrenergic antagonists lower arterial pressure?

    <p>By dilating veins to indirectly reduce arterial pressure</p> Signup and view all the answers

    In what condition can an alpha adrenergic antagonist be used to prevent injury?

    <p>Extravasated necrosis due to local vasoconstriction</p> Signup and view all the answers

    What is the therapeutic application of alpha blockade in BPH?

    <p>To treat the proliferation of the prostate gland</p> Signup and view all the answers

    What is the primary effect of overdose with an alpha-adrenergic agonist?

    <p>Hypertension due to excessive activation of A1 receptors on blood vessels</p> Signup and view all the answers

    What is the main therapeutic application of reversible competitive blockade?

    <p>Treatment of essential hypertension</p> Signup and view all the answers

    What is the specific therapeutic application of alpha blockade in Raynaud Disease?

    <p>Treatment of local vasoconstriction and prevention of injury</p> Signup and view all the answers

    In what condition does an alpha adrenergic antagonist cause the reduction of arterial pressure by indirect process?

    <p>Extravasated necrosis due to intense local vasoconstriction</p> Signup and view all the answers

    What is the direct effect of dilation of arterioles caused by adrenergic antagonists?

    <p>Reduction in cardiac output and arterial pressure</p> Signup and view all the answers

    What is the primary action of adrenergic antagonists when used for reversal of toxicity from alpha agonists?

    <p>Blocking the excessive vasoconstriction caused by the alpha agonist</p> Signup and view all the answers

    What differentiates most adrenergic antagonists from adrenergic agonists?

    <p>They are more selective than adrenergic agonists</p> Signup and view all the answers

    What is the primary symptom of Raynaud's disease?

    <p>Discoloration due to decreased circulation in toes and fingers</p> Signup and view all the answers

    Why is orthostatic hypotension a significant adverse effect of alpha-1 receptor blockade?

    <p>It is secondary to blockade of alpha receptors on veins, reducing muscle tone in the venous wall</p> Signup and view all the answers

    Which group of alpha adrenergic blocking agents produces selective A1 blockade?

    <p>Prazosin</p> Signup and view all the answers

    What is the most significant adverse effect associated with alpha-2 receptor blockade?

    <p>Potentiation of reflex tachycardia</p> Signup and view all the answers

    Which alpha adrenergic blocking agent can cause abnormal ejaculation and has an increased risk for rhinitis?

    <p>Tamsulosin</p> Signup and view all the answers

    What is the primary use of prazosin among the 'zosins' group of drugs?

    <p>Treatment of hypertension</p> Signup and view all the answers

    What is the specific reason for giving alpha-1 antagonists prior to surgery for pheochromocytoma?

    <p>To avoid manipulation of the tumor causing massive catecholamine release</p> Signup and view all the answers

    Why is impotence reversible once alpha-1 antagonist drug is discontinued?

    <p>'First-dose' effect leads to reversible impotence</p> Signup and view all the answers

    Which peripheral vascular disorder can be suppressed by preventing alpha-mediated base vasoconstriction?

    <p>Raynaud's disease</p> Signup and view all the answers

    What is the major reason for using alpha-1 antagonists long term if the pheochromocytoma tumor is inoperable?

    <p>To treat hypertension resulting from tumor activity</p> Signup and view all the answers

    What adverse effect results from sodium retention and increased blood volume due to reduced blood pressure caused by alpha-1 blockade?

    <p>Orthostatic hypotension</p> Signup and view all the answers

    What distinguishes prazosin from alfuzosin among the 'zosins' group of drugs?

    <p>Alfuzosin can prolong QT and should not be given with inhibitors of CYP34A, while prazosin does not have these effects.</p> Signup and view all the answers

    What is the main therapeutic application of phentolamine?

    <p>Treatment of pheochromocytoma</p> Signup and view all the answers

    How do beta adrenergic blockers prevent ischemia and pain?

    <p>By reducing oxygen demand and balancing it with oxygen supply</p> Signup and view all the answers

    What is a common long-term effect of beta adrenergic antagonist use on peripheral vascular resistance?

    <p>Decreased peripheral vascular resistance</p> Signup and view all the answers

    What is the main therapeutic application of beta adrenergic blockers in antianginal therapy?

    <p>Reducing oxygen demand</p> Signup and view all the answers

    What is the primary use of beta adrenergic antagonists in treating dysrhythmias?

    <p>Reducing electrical activity in the sinus node and atria</p> Signup and view all the answers

    What is the long-lasting effect of phenoxybenzamine receptor blockade?

    <p>Irreversible receptor blockade</p> Signup and view all the answers

    What are the approved applications of phentolamine?

    <p>Diagnosis and treatment of pheochromocytoma, prevention of tissue necrosis, reversal of soft tissue anesthesia</p> Signup and view all the answers

    What is the primary effect of beta adrenergic antagonists on cardiac workload?

    <p>Decreasing cardiac workload</p> Signup and view all the answers

    What are the adverse effects associated with phentolamine?

    <p>Orthostatic hypotension and reflex tachycardia</p> Signup and view all the answers

    What are the approved applications of phenoxybenzamine?

    <p>Diagnosis and treatment of pheochromocytoma, prevention of tissue necrosis</p> Signup and view all the answers

    Which adverse effect can be caused by the activation of B2 receptors in the lung?

    <p>Bronchoconstriction</p> Signup and view all the answers

    What is the primary therapeutic use of propranolol?

    <p>Prevention of migraine</p> Signup and view all the answers

    What is the effect of blocking B1 receptors in the heart by propranolol?

    <p>Decreased cardiac output</p> Signup and view all the answers

    Which adverse effect is specifically associated with the use of metoprolol?

    <p>Bradycardia</p> Signup and view all the answers

    What is the primary reason for using a B1 selective agent in patients with asthma who need a beta blocker?

    <p>To prevent bronchoconstriction</p> Signup and view all the answers

    What is the mechanism by which propranolol reduces the force of ventricular contraction?

    <p>Suppression of impulse conduction through the AV node</p> Signup and view all the answers

    What is the primary reason for minimizing the risk of rebound excitation when withdrawing beta blockers?

    <p>To prevent anginal pain or ventricular dysrhythmias</p> Signup and view all the answers

    What is the primary effect of metoprolol on heart rate?

    <p>Decreased heart rate</p> Signup and view all the answers

    What is the most significant adverse effect observed with Betaxolol and other beta blockers?

    <p>Bradycardia</p> Signup and view all the answers

    What is the primary reason for using a B1 selective agent in patients with diabetes mellitus who need a beta blocker?

    <p>To avoid hypoglycemia</p> Signup and view all the answers

    How do beta blockers contribute to the treatment of an MI?

    <p>They reduce the pain</p> Signup and view all the answers

    What is the mechanism by which beta blockers prevent tachydysrhythmia and angina in hyperthyroidism?

    <p>By normalizing the levels of sympathetic activity to the heart</p> Signup and view all the answers

    What is one of the therapeutic applications of beta blockers?

    <p>Stage fright</p> Signup and view all the answers

    What is a potential risk associated with using beta blockers in patients with heart failure or reduced cardiac reserve?

    <p>Insufficient tissue perfusion</p> Signup and view all the answers

    Why should beta blockers be discontinued in patients with stage D heart failure?

    <p>They exacerbate heart failure symptoms</p> Signup and view all the answers

    What is AV heart block defined as?

    <p>A delay in atrial impulse conduction through the AV node</p> Signup and view all the answers

    What effect do non-selective beta adrenergic blocking agents produce compared to cardioselective beta-adrenergic antagonists?

    <p>Broader spectrum of adverse effects</p> Signup and view all the answers

    What is a specific therapeutic use of non-selective beta blockade?

    <p>Treatment of glaucoma</p> Signup and view all the answers

    What is one of the adverse effects of Beta1 blockade?

    <p>Suppression of cardiac function</p> Signup and view all the answers

    What adverse effect can beta blockers precipitate in some patients?

    <p>Heart failure</p> Signup and view all the answers

    Which beta blockers have high solubility and primarily penetrate the blood-brain barrier?

    <p>Propranolol, Metoprolol</p> Signup and view all the answers

    What is the only approved indication for esmolol?

    <p>Emergency IV therapy of SVT</p> Signup and view all the answers

    Which beta blocker can cause postural hypotension?

    <p>Carvedilol</p> Signup and view all the answers

    Which beta blockers have a black box warning for abrupt discontinuation and increased risk for angina and MI?

    <p>Atenolol, Metoprolol</p> Signup and view all the answers

    Which type of adrenergic blocking drugs are used primarily for hypertension?

    <p>Indirect-acting antiadrenergic agents</p> Signup and view all the answers

    What is the main difference between labetalol, carvedilol, and nebivolol from other beta blockers?

    <p>They primarily block alpha adrenergic receptors</p> Signup and view all the answers

    What makes sotalol and esmolol unsuitable for treating hypertension?

    <p>They require maintenance of blood levels throughout the day</p> Signup and view all the answers

    What is the effect of activating A2 receptors located on presynaptic nerve terminals?

    <p>Decreased NE synthesis</p> Signup and view all the answers

    What is the main adverse effect associated with carvedilol, labetalol, and nebivolol?

    <p>Postural hypotension</p> Signup and view all the answers

    Which receptor activation do the indirect-acting antiadrenergic agents prevent by mechanisms not involving direct interaction with peripheral receptors?

    <p>A1 receptors</p> Signup and view all the answers

    What is the main pharmacological effect of clonidine?

    <p>Bradycardia and decrease in cardiac output</p> Signup and view all the answers

    Why is clonidine not recommended during pregnancy?

    <p>It can have adverse effects on the fetus</p> Signup and view all the answers

    What is a common adverse effect of clonidine experienced by 40% of patients?

    <p>Xerostomia (dry mouth)</p> Signup and view all the answers

    How does clonidine affect sympathetic outflow to the blood vessels and heart?

    <p>It reduces sympathetic outflow</p> Signup and view all the answers

    What is the route of administration for clonidine in epidural administration?

    <p>Solution for epidural administration</p> Signup and view all the answers

    In what area of the central nervous system does clonidine selectively activate A2 receptors?

    <p>Brainstem associated with autonomic regulation</p> Signup and view all the answers

    What is the primary mechanism of clonidine's action in reducing sympathetic outflow?

    <p>Selective activation of A2 receptors in the CNS</p> Signup and view all the answers

    Which adverse effect is specifically associated with clonidine withdrawal?

    <p>Rebound hypertension</p> Signup and view all the answers

    What is the primary therapeutic use of guanfacine?

    <p>Treatment of hypertension and ADHD</p> Signup and view all the answers

    How do guanfacine and clonidine benefit patients with hypertension?

    <p>By activating brainstem A2 adrenergic receptors</p> Signup and view all the answers

    What distinguishes methyldopate from methyldopa?

    <p>Route of administration</p> Signup and view all the answers

    What is the only therapeutic use of methyldopa and methyldopate?

    <p>Treatment of hypertension</p> Signup and view all the answers

    Which organization designated methyldopa as one of the preferred drugs for managing hypertension during pregnancy?

    <p>American College of Obstetricians and Gynecologists</p> Signup and view all the answers

    What are the adverse effects associated with methyldopa?

    <p>Hemolytic anemia and hepatic necrosis</p> Signup and view all the answers

    What is the primary reason for designating methyldopa as one of the preferred drugs for managing hypertension during pregnancy?

    <p>No fetal harm associated with this medication</p> Signup and view all the answers

    What are the other two drugs designated by the American College of Obstetricians and Gynecologists for managing hypertension during pregnancy?

    <p>Labetalol and nifedipine</p> Signup and view all the answers

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