NE Agonists and Blockers
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Questions and Answers

Which adrenergic receptor type is primarily responsible for vasoconstriction?

  • Beta 2
  • Alpha 2
  • Beta 1
  • Alpha 1 (correct)

What is the primary effect of Beta 2 adrenergic receptor activation?

  • Increased heart rate
  • Vasoconstriction
  • Bronchodilation (correct)
  • Increased peripheral resistance

What is the main outcome of the re-uptake of norepinephrine into the neuron?

  • Activation of muscle contraction
  • Decreased norepinephrine levels in the synapse (correct)
  • Enhanced adrenergic receptor sensitivity
  • Increased blood pressure

How does Alpha 2 adrenergic receptor activation affect insulin release?

<p>Inhibits insulin release (B)</p> Signup and view all the answers

Which of the following is classified as a direct-acting adrenergic drug?

<p>Phenylephrine (B), Epinephrine (D)</p> Signup and view all the answers

Which adrenergic drug class is known for stimulating norepinephrine release?

<p>Indirect-acting (A)</p> Signup and view all the answers

What physiological effect results from Beta 1 receptor activation?

<p>Increased myocardial contractility (B)</p> Signup and view all the answers

What role does MAO have in the control of norepinephrine levels?

<p>Breaks down norepinephrine (D)</p> Signup and view all the answers

What is the primary role of beta 2 receptors in the body?

<p>Relaxing smooth muscles in various systems like respiratory and vascular (B)</p> Signup and view all the answers

Which of the following statements about sympathomimetic drugs is true?

<p>They can act directly by binding to receptors or indirectly by releasing norepinephrine. (C)</p> Signup and view all the answers

What is the effect of dopamine on renal blood vessels?

<p>Dilation and decreased resistance, resulting in lowered blood pressure (C)</p> Signup and view all the answers

Which mechanism is primarily associated with indirect agonists in the context of neurotransmitter release?

<p>Releasing norepinephrine stored in neuron vesicles (C)</p> Signup and view all the answers

What effect do beta 2 receptors have on pancreatic beta cells?

<p>Trigger increased insulin release into the bloodstream (A)</p> Signup and view all the answers

Which drug is classified as an indirect acting agonist?

<p>Amphetamine (B)</p> Signup and view all the answers

Which receptor subtype has a higher affinity for epinephrine over norepinephrine?

<p>Beta 2 (D)</p> Signup and view all the answers

Which mechanism is affected by Agonist drug binding to adrenergic receptors?

<p>Increased cAMP production (C)</p> Signup and view all the answers

What is the primary action of beta adrenergic agonists on muscle cells?

<p>Activation of muscle hypertrophy (A)</p> Signup and view all the answers

Which of the following is not classified as a sympathomimetic?

<p>Bupropion (A)</p> Signup and view all the answers

Which substance is primarily known as a beta-agonist used for respiratory issues?

<p>Albuterol (B)</p> Signup and view all the answers

Which sympathomimetic drug is primarily used as a vasoconstrictor?

<p>Oxymetazoline (D)</p> Signup and view all the answers

Which of the following receptor types binds norepinephrine equally to epinephrine?

<p>Beta 1 (D)</p> Signup and view all the answers

What is the primary clinical effect of phenylephrine when it acts as an alpha 1 agonist?

<p>Nasal decongestant (C)</p> Signup and view all the answers

Which drug is indicated for increasing blood pressure through alpha 1 receptor stimulation?

<p>Midodrine (A)</p> Signup and view all the answers

Which beta agonist is primarily used to relieve bronchoconstriction?

<p>Albuterol (B)</p> Signup and view all the answers

What is the role of isoproterenol in terms of receptor interaction?

<p>Beta 1 = Beta 2 agonist (A)</p> Signup and view all the answers

What is the primary action of epinephrine during anaphylactic shock?

<p>Increasing cardiac output (D)</p> Signup and view all the answers

Which of the following drugs is classified as a pure beta agonist?

<p>Dobutamine (C)</p> Signup and view all the answers

Which beta agonist is commonly used for acute asthmatic bronchoconstriction?

<p>Terbutaline (D)</p> Signup and view all the answers

What pharmacological effect does clonidine have through alpha 2 receptor agonism?

<p>Lower blood pressure (C)</p> Signup and view all the answers

What is the primary therapeutic use of amphetamines?

<p>Treatment of narcolepsy and attention deficit disorder (B)</p> Signup and view all the answers

Which type of medication is used topically for reducing conjunctival itching caused by allergies?

<p>Alpha agonists (D)</p> Signup and view all the answers

Which adrenergic receptors are primarily involved in suppressing premature labor?

<p>Beta 2 receptors (A)</p> Signup and view all the answers

What can beta activation lead to in terms of blood pressure regulation?

<p>Decreased peripheral resistance (B)</p> Signup and view all the answers

Which action is associated with alpha agonists in the management of eye conditions?

<p>Increase outflow of aqueous humor (B)</p> Signup and view all the answers

In the genitourinary tract, which receptor type promotes contraction of the bladder?

<p>Alpha receptors (B)</p> Signup and view all the answers

Which of the following effects do beta receptors on fat cells primarily have?

<p>Increase lipolysis (C)</p> Signup and view all the answers

What effect do beta 2 agonists have on bronchial smooth muscle?

<p>Promote relaxation (D)</p> Signup and view all the answers

What is the primary effect of epinephrine?

<p>It causes a rise in blood pressure. (C)</p> Signup and view all the answers

Which of the following correctly describes isoproterenol?

<p>It is a potent beta agonist with little effect on alpha receptors. (B)</p> Signup and view all the answers

In the context of anaphylaxis, which of the following actions is attributed to epinephrine?

<p>It aids in reversing the drop in blood pressure. (B)</p> Signup and view all the answers

What is a potential cardiovascular adverse effect of sympathomimetic drugs?

<p>Cardiac failure. (C)</p> Signup and view all the answers

Which receptors are primarily activated by norepinephrine and epinephrine?

<p>Alpha and beta receptors. (B)</p> Signup and view all the answers

What role does modafinil have in the context of sympathomimetic drugs?

<p>It serves as a stimulant for narcolepsy. (C)</p> Signup and view all the answers

Which of the following sympathomimetic drugs is used for local anesthesia in combination with norepinephrine?

<p>Cocaine. (D)</p> Signup and view all the answers

What outcome is associated with the action of alpha 1 activation from sympathomimetic drugs?

<p>Vasoconstriction and increased blood pressure. (C)</p> Signup and view all the answers

Metoprolol is selective for which adrenoceptors?

<p>Beta-1 adrenoceptors (B)</p> Signup and view all the answers

What effects does metoprolol have on the cardiovascular system?

<p>Decreases heart rate and blood pressure (A)</p> Signup and view all the answers

In which organ is metoprolol primarily metabolized (biotransformed)?

<p>Liver (A)</p> Signup and view all the answers

Why must beta-adrenergic antagonists be used with caution in asthmatics?

<p>They can cause bronchospasm. (A)</p> Signup and view all the answers

Which of the following are reversible alpha receptor agonists?

<p>phentolamine (A), prazosin (C)</p> Signup and view all the answers

Which of the following is an irreversible alpha receptor antagonist?

<p>phenoxybenzamine (B)</p> Signup and view all the answers

Match each alpha blocker drug to its description

<p>phenoxybenzamine = Major ADR is orthostatic hypotension, drug enters CNS and causes sedation and nausea phentolamine = ADR, compensatory cardiac stimulation, leading to severe tachycardia, arrhythmias, myocardial ischemia prazosin = selective alpha 1 blocker, used widely to treat hypertension also relaxes smooth muscle in the prostrate, used to treat BHP terazosin = reversible alpha 1 blocker, used in hypertension and to treat BHP</p> Signup and view all the answers

Match each alpha blocker drug to its description

<h1>doxazosin = hypertension and BHP tamsulosin = most efficacy of all for treatment BHP, acts mostly on prostate ; alpha 1A subtypes of alpha receptors; orthostatic hypotension is possible</h1> <p>=</p> Signup and view all the answers

What are non-selective alpha blockers used to treat?

<p>Pheochromocytoma (adrenal bone tumor) (C)</p> Signup and view all the answers

Which drug has a high bioavailability following oral dosing?

<p>Pindolol (B)</p> Signup and view all the answers

Which drug has a short half-life of 10 minutes?

<p>Esmolol (A)</p> Signup and view all the answers

Which drug is highly lipid soluble and can enter the CNS?

<p>Propranolol (A)</p> Signup and view all the answers

What is the mechanism of action (MOA) of all local anesthetics?

<p>Blocking sodium channels in neurons (B)</p> Signup and view all the answers

Match each drug to its selectivity, partial agonist activity and lipid solubility

<p>B1 selective = metoprolol; atenolol; nebivolol No Partial agonist activity = propranolol; metoprolol; atenolol; nebivolol; timolol; nadolol Partial agonist activity = pindolol Low lipid solubility = atenolol; nebivolol; nadolol</p> Signup and view all the answers

Match each drug to its lipid solubility and half life

<p>Moderate lipid solubilty = metoprolol; pindolol; timolol High lipid solubility = propranolol Longer half-life (more than 6 hours) = atenolol; metoprolol; nebivolol; nadolol Shorter half life (less than 7 hours) = pindolol; propranolol; timolol</p> Signup and view all the answers

What drug is used for both performance anxiety and migraines?

<p>Propranolol (A)</p> Signup and view all the answers

Which of the following displaces stored biogenic amines from nerve terminals?

<p>tyramine (B)</p> Signup and view all the answers

Which of the following block the reuptake of the amine back into storage in the neuron?

<p>cocaine (A), tricyclic (C), antidepressants (D)</p> Signup and view all the answers

Which of the following are antagonists to phenylephrine? (Select all that apply)

<p>prazosin (A), tamsulosin (C)</p> Signup and view all the answers

Which of the following is an antagonist to isoproterenol?

<p>propranolol (A)</p> Signup and view all the answers

Match each receptor type to its description

<p>Alpha 1 = coupled to phospholipase C which forms inositol trisphosphate (IP3) and diacylglycerol (DAG); IP3 increases intracellular calcium which activate various protein kinases Alpha 2 = inhibits adenylyl cyclase which decreases cAMP levels Beta 1, 2, 3 = all stimulate adenylyl cyclase and increase cAMP levels DA receptors = all stimulate adenylyl cyclase and increase cAMP levels</p> Signup and view all the answers

Which desensitization is described below: caused by repeated exposure to agonist drug

<p>Homologous Desensitization (A)</p> Signup and view all the answers

Which desensitization is described below: receptor A undergoes homologous desensitization which causes receptor B which never saw the agonist drug but it becomes desensitized also

<p>Heterologous Desensitization (B)</p> Signup and view all the answers

What is a good example of a drug that inhibits the NET and raises NE, which stimulates alpha and beta receptors?

<p>Cocaine (A)</p> Signup and view all the answers

Which alpha 1 agonist leads to urinary retention? It is also used to treat orthostatic hypertension

<p>midodrine (A)</p> Signup and view all the answers

Which drug is both an agonist and antagonist at alpha 2 receptors and stops NE from binding or being produced?

<p>clonidine (B)</p> Signup and view all the answers

What is the most common clinical presentation of a pheochromocytoma?

<p>Catecholamine excess leading to high blood pressure (B)</p> Signup and view all the answers

Which of the following alpha blockers is indicated for the treatment of urinary obstruction in benign prostatic hyperplasia (BPH)?

<p>Prazosin (C), Doxazosin (D)</p> Signup and view all the answers

What commonly occurs during postural changes associated with alpha blocker use?

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

What is a common side effect seen with the use of alpha antagonists?

<p>Reflex tachycardia (C)</p> Signup and view all the answers

Which of the following conditions is NOT primarily treated with alpha blockers?

<p>Chronic obstructive pulmonary disease (COPD) (A)</p> Signup and view all the answers

Which drug is specifically mentioned as the drug of choice for managing pheochromocytoma post-operatively?

<p>Phenoxybenzamine (B)</p> Signup and view all the answers

What is the mechanism by which ergot derivatives primarily help in the treatment of migraines?

<p>Blocking alpha receptors (B)</p> Signup and view all the answers

What is a notable clinical use of selective alpha1 antagonists?

<p>Controlling hypertension and benign prostatic hyperplasia (A)</p> Signup and view all the answers

In what way do sympatholytics primarily exert their effects?

<p>By blocking endogenous catecholamine action (D)</p> Signup and view all the answers

What is the primary therapeutic use of clonidine, an alpha 2 agonist?

<p>Reduce hypertension (C)</p> Signup and view all the answers

What is primarily released by pheochromocytomas that leads to symptoms of palpitations and sweating?

<p>Norepinephrine and epinephrine (D)</p> Signup and view all the answers

Which factor affects the duration of action of reversible alpha antagonists?

<p>The half-life and maintenance of plasma concentration (D)</p> Signup and view all the answers

Which adrenoceptor antagonist is classified as a non-selective beta blocker?

<p>Propranolol (D)</p> Signup and view all the answers

How might beta blockers affect individuals who are insulin-dependent?

<p>Exacerbate hypoglycemia (B)</p> Signup and view all the answers

Which of these drugs is specifically indicated for heart rate reduction?

<p>Atenolol (D)</p> Signup and view all the answers

What adverse effect is associated with high lipid solubility beta antagonists?

<p>Sleep disturbances and depression (A)</p> Signup and view all the answers

Which muscarinic agonist is mentioned in the context of parasympathetic activity?

<p>Muscarine (C)</p> Signup and view all the answers

What effect is commonly associated with the use of atenolol compared to other beta blockers?

<p>Reduced central nervous system side effects. (A)</p> Signup and view all the answers

What is the effect of beta antagonists on intraocular pressure in patients with glaucoma?

<p>They reduce intraocular pressure by blocking aqueous humor production. (A)</p> Signup and view all the answers

Which drug is primarily indicated for the treatment of hypertension combined with diuretics and/or vasodilators?

<p>Atenolol (D)</p> Signup and view all the answers

How do beta 2 selective beta blockers affect metabolism, particularly in diabetes patients?

<p>They inhibit lipolysis, which can be problematic for diabetic patients. (A)</p> Signup and view all the answers

What is the primary therapeutic use of metoprolol in clinical practice?

<p>It is utilized to manage angina and improve exercise tolerance. (A)</p> Signup and view all the answers

In treating hyperthyroidism, which effect do beta blockers like propranolol exhibit?

<p>They help in controlling elevated heart rates due to excess hormones. (B)</p> Signup and view all the answers

Flashcards

Adrenergic Receptors

Neuroreceptors that bind to norepinephrine (NE) and epinephrine, triggering various physiological responses.

Alpha1 Adrenergic Receptors

Cause vasoconstriction, increased blood pressure, and mydriasis (pupil dilation).

Alpha2 Adrenergic Receptors

Inhibit NE release and insulin release.

Beta1 Adrenergic Receptors

Cause tachycardia (increased heart rate), increased lipolysis, and increased myocardial contractility.

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Beta2 Adrenergic Receptors

Cause vasodilation, bronchodilation, and relaxation of uterine smooth muscle.

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Direct-Acting Adrenergic Drugs

Drugs that directly bind and activate adrenergic receptors.

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Indirect-Acting Adrenergic Drugs

Drugs that cause the release of norepinephrine (NE).

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Mixed-Action Adrenergic Drugs

Drugs that directly activate adrenergic receptors and cause the release of NE.

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Adrenoceptor Agonists

Drugs that activate adrenoceptors, mimicking the effects of norepinephrine (NE) and epinephrine (EP).

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Beta 2 Receptors

Stimulation causes relaxation of smooth muscles in the lungs, uterus, and blood vessels.

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Dopamine Receptors

Located in the kidneys and other areas; cause dilation of blood vessels and decreased blood pressure.

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Sympathomimetic Drugs

Drugs that mimic the actions of norepinephrine (NE) and epinephrine (EP).

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Indirect Agonists

Drugs that release norepinephrine (NE) from nerve terminals, having widespread, nonspecific effects.

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Sympathomimetics

Drugs that mimic the effects of the sympathetic nervous system (SNS) by activating adrenergic receptors.

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What is the effect of activating Adenylate Cyclase?

Adenylate cyclase converts ATP to cAMP, which activates kinases, leading to phosphorylation and ultimately muscle contraction.

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What is the difference between Alpha and Beta Adrenergic Receptors?

Alpha receptors are primarily involved in vasoconstriction and other responses while Beta receptors are involved in bronchodilation, increased heart rate and other responses.

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What are some examples of sympathomimetic medications?

Examples include epinephrine, norepinephrine, dopamine, phenylephrine, albuterol, and many others.

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Alpha 1 Agonist Action

Alpha 1 agonists primarily cause vasoconstriction, leading to increased blood pressure and potential for nasal decongestion.

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Phenylephrine

A classic alpha 1 agonist used for nasal decongestion, it directly activates alpha 1 receptors causing vasoconstriction in the nasal passages.

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Isoproterenol (Isuprel®)

This drug is a potent beta 1 and beta 2 agonist, widely used in emergency situations due to its strong effect on the heart and lungs.

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Beta 2 Agonist Use

Beta 2 agonists are the primary treatment for acute asthmatic bronchoconstriction. Their action relaxes airway smooth muscle, opening up the airways.

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Albuterol (Proventil®)

A commonly used beta 2 agonist, it relieves bronchoconstriction and improves breathing in asthma patients by selectively activating beta 2 receptors.

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Epinephrine in Anaphylaxis

Epinephrine is the drug of choice to treat anaphylactic shock, a severe allergic reaction. It acts by stimulating both alpha and beta receptors to counteract the life-threatening symptoms.

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Clonidine (Catapres®)

This alpha 2 agonist acts in the central nervous system (CNS) to lower blood pressure by reducing the release of norepinephrine.

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Midodrine (ProAmatine®)

A direct-acting alpha 1 agonist that increases blood pressure by constricting blood vessels.

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Adrenoceptor Agonists: CNS

Drugs that stimulate adrenergic receptors in the central nervous system (CNS), often used for weight loss, attention deficit disorder, narcolepsy, and sometimes abused for mood-altering effects.

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Adrenoceptor Agonists: Eye

Drugs that stimulate adrenergic receptors in the eye, used to reduce conjunctival itching caused by allergies (phenylephrine) and treat glaucoma (epinephrine).

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Adrenoceptor Agonists: Genitourinary Tract

Drugs that stimulate adrenergic receptors in the genitourinary tract, primarily beta 2 agonists used to suppress premature labor (ritodrine, terbutaline) and alpha agonists (like ephedrine) to improve urinary continence.

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Sympathomimetics: Cardiovascular Effects

Drugs that mimic the sympathetic nervous system, affecting blood vessels (alpha for constriction, beta 2 for relaxation), heart (beta 1 for increased heart rate and contractility), and blood pressure (alpha raises, beta lowers).

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Sympathomimetics: Eye Effects

Drugs that mimic the sympathetic nervous system, affecting the eye by increasing aqueous humor outflow (alpha) and decreasing its production (beta), influencing eye pressure.

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Sympathomimetics: Respiratory Effects

Drugs that mimic the sympathetic nervous system, affecting the respiratory system primarily through beta 2 receptors, causing relaxation of bronchial smooth muscle, leading to bronchodilation.

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Sympathomimetics: GI Effects

Drugs that mimic the sympathetic nervous system, affecting the gastrointestinal (GI) tract by relaxing smooth muscles (beta) and decreasing acetylcholine release (alpha 2), affecting digestion and motility.

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Sympathomimetics: Other Effects

Drugs that mimic the sympathetic nervous system, affecting various systems including the uterus (beta for relaxation, alpha for contraction), exocrine glands (controlling secretions), and fat cells (increasing lipolysis).

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Epinephrine (Adrenaline)

A potent vasoconstrictor and cardiac stimulant that increases blood pressure.

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Norepinephrine

Similar effects to epinephrine, but slightly less potent.

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Isoproterenol

A strong beta agonist, primarily affecting beta receptors. Dilates blood vessels.

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How do Sympathomimetics Raise Blood Pressure?

Direct-acting drugs like phenylephrine or methoxamine increase blood pressure by constricting blood vessels.

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Sympathomimetics for Anaphylaxis

Epinephrine (EP) is used to counter the effects of anaphylaxis by reversing low blood pressure, bronchospasm, and congestion.

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General Cardiovascular Adverse Effects of Sympathomimetics

These drugs can lead to hypertension, increased risk of heart problems, and cardiac failure.

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Sympathomimetics and the CNS

Only drugs like cocaine and amphetamine can cross the blood-brain barrier easily, leading to central nervous system side effects.

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Alpha Antagonists

Drugs that block alpha receptors, primarily found on vascular smooth muscle, leading to a decrease in blood pressure.

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Phentolamine

Non-selective alpha antagonist that blocks both alpha 1 and alpha 2 receptors, used to lower blood pressure and treat pheochromocytoma.

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Epinephrine Reversal

A phenomenon where activating alpha and beta receptors in the same tissue leads to opposing effects on blood pressure. For example, epinephrine increases blood pressure by activating both alpha and beta receptors, but a selective alpha 1 antagonist blocks both alpha and beta actions of epinephrine, resulting in lowered blood pressure.

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Pheochromocytoma

A tumor of the sympathetic nervous system that produces excessive norepinephrine and epinephrine, leading to hypertensive crisis.

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Alpha 2 Agonists

Drugs that activate alpha 2 receptors, ultimately reducing sympathetic outflow from the brain and norepinephrine release from neurons, lowering blood pressure.

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Clonidine

An alpha 2 agonist used to treat hypertension by reducing sympathetic activity.

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Sympatholytics

Drugs that reduce sympathetic activity, generally by blocking adrenergic receptors.

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Alpha 1 Selective Antagonists

Drugs that specifically block alpha 1 receptors, leading to vasodilation and lower blood pressure.

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What are Sympatholytics?

Drugs that block the effects of the sympathetic nervous system by antagonizing adrenergic receptors. They can be selective for specific receptor subtypes or non-selective, affecting multiple receptors.

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What is Pheochromocytoma?

A tumor of the adrenal medulla that releases excessive amounts of catecholamines (epinephrine and norepinephrine), causing high blood pressure, sweating, palpitations, and headaches.

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What are Non-Selective Alpha Antagonists used for?

These drugs are primarily used for treating Pheochromocytoma, a rare tumor. They are not selective and block both alpha 1 and alpha 2 receptors.

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What are Alpha-1 Selective Antagonists used for?

These drugs are used for treating hypertension and benign prostatic hyperplasia (BPH). They specifically block alpha 1 receptors, which are linked to vasoconstriction and prostate function.

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What are Beta Antagonists used for?

These drugs are used for treating various conditions, including hypertension, ischemic heart disease, and neurological disorders. They block beta receptors, affecting heart rate, blood pressure, and other bodily functions.

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What's the difference between Reversible and Irreversible Alpha Antagonists?

Reversible alpha antagonists have a duration of action tied to their half-life, while irreversible alpha antagonists form a strong bond with the receptor and their effects last for days. They require new receptor synthesis to restore function.

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Which drug is used to stabilize patients before surgery for Pheochromocytoma?

Phenoxybenzamine is an irreversible alpha blocker used pre-operatively to control the high blood pressure and other symptoms caused by the tumor's catecholamine release.

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What is Phentolamine used for?

Phentolamine is a reversible alpha blocker that is used to treat hypertensive episodes associated with Pheochromocytoma. It can also be administered intravenously to reverse the effects of alpha agonists.

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Pheochromocytoma Location

A tumor most often found in the adrenal gland that releases excessive amounts of norepinephrine and epinephrine, causing high blood pressure, sweating, palpitations, and headaches.

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Pheochromocytoma Symptoms

A condition characterized by high blood pressure, sweating, palpitations, and headaches due to excessive release of norepinephrine and epinephrine from a tumor in the adrenal gland.

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Alpha Blockers and Blood Pressure?

Alpha blockers cause vasodilation, leading to a decrease in blood pressure. This effect is more pronounced when standing due to the increased need for norepinephrine to maintain blood pressure.

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Alpha Blockers Side Effects

Alpha blockers can cause postural hypotension (low blood pressure upon standing) and reflex tachycardia (increased heart rate as a response to lowered blood pressure).

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Phenoxybenzamine

An irreversible alpha blocker with a long duration of action (14-48+ hours), used to treat pheochromocytoma and other conditions.

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Prazosin

A selective alpha 1 blocker with a relatively low incidence of tachycardia, used to treat hypertension and benign prostatic hyperplasia (BPH).

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Terazosin

A reversible alpha 1 antagonist with a long half-life, used to treat hypertension and benign prostatic hyperplasia (BPH).

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Doxazosin

A long-acting alpha 1 blocker with a half-life of 22 hours, used to treat hypertension and benign prostatic hyperplasia (BPH).

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Beta Blockers: Cardiovascular Action

Beta blockers decrease blood pressure by reducing heart rate, constricting blood vessels, and inhibiting the renin-angiotensin system.

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Beta Blockers: Respiratory Action

Beta blockers can cause airway constriction by blocking the beta 2 receptors. Selective beta 1 blockers have less effect on the lungs.

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Beta Blockers: Eye Action

Beta blockers increase pressure in the eye, potentially leading to glaucoma. They are also used topically to treat glaucoma.

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Beta Blockers: Metabolic Effects

Beta blockers can inhibit lipolysis (fat breakdown) and reduce glycogenolysis in the liver. Caution is advised with diabetes patients.

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Beta Blockers: Common Uses

Beta blockers are widely used to treat hypertension, ischemic heart disease, cardiac arrhythmias, and glaucoma.

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Beta Blockers: Neurological Uses

Beta blockers, especially propranolol, are used to treat migraines and other neurological conditions.

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Propranolol

The first beta blocker drug, non-selective, with numerous effects on the central nervous system.

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Timolol

A non-selective beta blocker used topically for the treatment of glaucoma.

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Alpha Blockers: Clinical Use

Alpha blockers are used primarily to treat hypertension (high blood pressure) and pheochromocytoma (a tumor that releases excessive catecholamines).

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Beta Blockers: Clinical Use

Beta blockers are used to treat hypertension, angina (chest pain), heart failure, and other conditions associated with the cardiovascular system. They are also used to manage stage fright.

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Non-selective Beta Blockers: Risks

Non-selective beta blockers can worsen asthma due to their blocking of beta-2 receptors in the lungs, and they can exacerbate hypoglycemia in insulin-dependent patients.

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Beta Blockers: CNS Effects

Beta blockers, particularly non-selective and high lipid-soluble ones, can cause CNS side effects like sedation, sleep disturbance, and depression.

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Reversible vs. Irreversible Alpha Blockers

Reversible alpha blockers have a duration of action tied to their half-life, while irreversible alpha blockers form a strong bond with the receptor and their effects last for days. They require new receptor synthesis to restore function.

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What are beta blockers?

Drugs that block beta receptors, resulting in effects such as reduced heart rate, blood pressure control, and other physiological changes.

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What are beta blockers used for?

Beta blockers are widely used for conditions like hypertension, angina, heart failure, and even to manage stage fright.

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What are alpha blockers used for?

Alpha blockers are primarily used to treat hypertension and pheochromocytoma, a tumor that releases excessive catecholamines.

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What are the effects of beta blockers on the heart?

Beta blockers decrease heart rate and blood pressure by blocking beta receptors in the heart.

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What are the effects of alpha blockers on blood vessels?

Alpha blockers cause vasodilation (widening of blood vessels) leading to a decrease in blood pressure.

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What are some examples of beta blockers?

Common beta blockers include propranolol, atenolol, metoprolol, and timolol. Each has specific properties and uses.

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Study Notes

Pharmacology I, Chapter 9: NE Agonists (Sympathomimetics)

  • Case Study: A 68-year-old male presented with lightheadedness upon standing, worsened by meals, decreased sweating, and urinary retention. He was taking the alpha-1 antagonist, tamsulosin, for urinary retention, but it worsened his orthostatic hypotension. His supine blood pressure was 167/84 mmHg and standing blood pressure was 106/55 mmHg. Heart rate did not compensate. The diagnosis was pure autonomic failure, unrelated to other diseases or drugs.

  • Case Study (continued): The patient had lost sympathetic tone. Tamsulosin, an alpha blocker, worsened his condition. Midodrine, an alpha agonist, might be helpful. The patient should avoid over-the-counter sympathomimetics and sympatholytics.

  • Catecholamines: Adrenergic neurotransmitters include norepinephrine, epinephrine, and dopamine. Chemical structures of each are shown.

  • Adrenergic Neurotransmitter Discovery: J. Axelrod (1912-2004) won the Nobel Prize in 1970 for discovering the uptake and release of catecholamine neurotransmitters.

  • Sympathomimetics (Adrenergic Agonists): These drugs mimic the actions of the sympathetic nervous system. Adrenal glands (L. add + renal), sympathetic nervous system, and adrenergic neurons release norepinephrine (NE). Locations are in the CNS and linking between ganglia and effector organs within the peripheral nervous system (PNS).

  • Sympathetic Drugs/Terms: Norepinephrine (NE), Epinephrine (EP), Dopamine (DA) are catecholamines. Derived from the amino acid tyrosine. Adrenergics (Gr. work) NE, EP, DA. (Commonly used terms to refer to these substances)

  • Receptor Organization, Sympathetic/Parasympathetic Pathway: The information presented in diagram form, showing the CNS, ACh, NE, adrenergic receptors (α1, α2, β1, β2). Diagram also presents the parasympathetic and somatic pathways.

  • NE at Adrenergic Neurons: Steps 1-6 in the synthesis, storage, release, receptor binding, re-uptake, and removal of NE from the synapse.

  • Adrenergic Receptors: Alpha1: Actions include vasoconstriction, increased peripheral resistance, increased blood pressure (BP), mydriasis, increased closure of the bladder sphincter.

  • Adrenergic Receptors: Alpha2: Actions include inhibition of NE release, inhibition of insulin release.

  • Adrenergic Receptors: Beta1: Actions include tachycardia, increased lipolysis, increased myocardial contractility, increased renin release.

  • Adrenergic Receptors: Beta2: Actions include vasodilation, decreased peripheral resistance, bronchodilation, relaxation of uterine smooth muscle.

  • Adrenoceptor Agonists & Sympathomimetics Drugs (Table 9-1): This table lists receptor type, agonist, antagonist, G protein, effects, and chromosome location. (Detailed Table)

  • Adrenergic Drugs (Direct-Acting/Indirect-Acting): A direct-acting drug binds to receptors (e.g., epinephrine, norepinephrine, isoproterenol, phenylephrine). An indirect-acting drug causes the release of norepinephrine (e.g., tyramine, amphetamine).

  • Adrenergic Drugs (Mixed Action): This category includes drugs with both direct- and indirect-acting effects (e.g., ephedrine, metaraminol).

  • Cardiac Innervation: Parasympathetic (ACh) and sympathetic (NE) systems. NE causes constriction (+), ACh causes relaxation (-). Diagram also presents blood vessels and the heart.

  • Sympathomimetics: This section explains the categories and different type of drugs.

  • Relative receptor affinities of Adrenergic Agonists (Table 9-2): This table provides details on the relative binding affinities of various agonists to different receptor subtypes (e.g., α1, α2, β1, β2). (Detailed Table)

  • Distribution of adrenoceptor subtypes (Table 9-3): Details on the presence and actions of receptor subtypes on various tissues and organs. (Detailed Table)

  • Alpha 1 Receptors: Locations (vascular smooth muscle, pupil dilator muscle, pilomotor smooth muscle), effect of activation (contraction).

  • Alpha 2 Receptors: Locations (adrenal and cholinergic nerve terminals, platelets, smooth muscle, fat cells), effect of activation (inhibition of NE release, inhibition of insulin release, inhibition of lipolysis)

  • Beta 1 Receptors: Location (heart, juxtaglomerular cells), effect of activation (increase heart rate/force).

  • Beta 2 Receptors: Location (smooth muscle, skeletal muscle, liver), effect of activation (muscle relaxation, glycogenolysis).

  • Dopamine Receptors: Locations and functions. Different types and effects. Activation stimulates adenyl cyclase and increases cAMP second messenger.

  • Receptor Desensitization: Repeated exposure leads to a decrease in receptor response. There are homologous (in the exposed receptor) and heterologous (in other receptors) forms

  • Points to Remember: Important features and locations of Alpha 1, Beta 1, and Beta 2 receptors highlighted, summarizing their functions.

  • Pharmacokinetics of Isoproterenol/Methoxamine: Includes information on absorption and distribution depending on substitutions in the chemical structure.

  • Beta Agonists (Table): A table with examples, receptor subtypes, and clinical effects. List includes examples of drug names.

  • Alpha Receptor Agonists (Table): Another table with examples, receptor subtypes, and clinical effects. List includes example of drug names.

  • Anaphylaxis: Epinephrine is the treatment of choice.

  • Bronchi (asthma): Beta agonists (mostly Beta 2) treat acute asthmatic bronchoconstriction with short-acting examples such as terbutaline, albuterol, and metaproterenol.

  • Cardiovascular: NE increases blood flow in acute heart failure and some types of shock. Beta 1 agonists useful here.

  • CNS effects of Amphetamines: Weight loss, attention-deficit disorder, narcolepsy, mood altering effects.

  • Eye drug effects: Alpha agonists are used topically for conjunctival itching and for glaucoma.

  • Genitourinary Tract: Beta 2 agonists used to suppress premature labor and ephedrine for continence problems. Alpha receptors are also involved in the bladder.

  • Summary I and Summary 2: These pages include summary points on various aspects of adrenergic agonists, and how to organize, classify, or categorize them.

  • Cardiovascular Effects of NE: NE causes total peripheral resistance increase, leading to arterial pressure elevation. Also causes vascular bed constriction and a subsequent increase in BP. In response to higher BP, the body activates parasympathetic output to the heart, increasing the heartbeat. Despite this, norepinephrine activation of beta 1 receptors causes a decrease in the heart rate.

  • Specific Sympathomimetic Drugs: Clinically relevant drugs, their classifications, and use cases described more specifically.

  • Selective Sympathomimetics: Including dexmedetomidine, tyramine, and others, based on specificity and use.

  • Clonidine (Catapres®): An alpha 2 agonist, lowering sympathetic outflow, reducing heart rate, and having multiple functions with a presynaptic/postsynaptic effect.

  • Dopamine (Intropin®): A dopamine receptor agonist, primarily used as a vasodilator at low doses for renal and coronary blood vessels. In high doses, it functions more like noradrenaline. Activates beta 1 receptors.

  • Importance of Receptor Type in Clinical Practice: Focuses on a patient with reactive airway disease and a mild heart attack. The need to use beta 2 receptor agonists targeting the lung but not stimulating the heart is emphasized.

  • Epinephrine (Adrenalin): Potent vasoconstrictor and cardiac stimulant, increasing blood pressure.

  • Norepinephrine: Similar effects to epinephrine.

  • Isoproterenol: Potent beta agonist primarily, with limited effect on alpha receptors, and a potent vasodilator effect.

  • Sympathomimetic Drugs (General): Raising blood pressure via drug reactions, decreased blood volume, and infections via reduced blood flow in surgery and local anesthesia, to reduce diffusion and efficacy. Shock is also mentioned.

  • Sympathomimetics (Effects): Anaphylactic shock, caused by immediate IgE-mediated reactions, addressed and reversed by epinephrine (EP). CNS effects are discussed for drug use, like modafinil (amphetamine analog) in narcolepsy and for ADHD (methylphenidate, clonidine).

  • Sympathomimetic Receptors, General (Summary): Describes receptor subtypes, specificity, and activation effects, like varying receptor subtypes and their varied activation pathways to achieve activation/inactivation of an action.

  • Agonist Drug Binding Mechanism: Detailed mechanism to achieve activation (e.g., activation of G proteins and cAMP, downstream signaling pathways).

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Related Documents

Pharmacology I - PM 716 C9 NE Agonists Slides PDF
PM716 Pharmacology I - NE Blockers PDF

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