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Questions and Answers
Which receptor activation is primarily responsible for vasoconstriction?
Which receptor activation is primarily responsible for vasoconstriction?
- Alpha-1 (correct)
- Beta-1
- Beta-2
- Alpha-2
What is a common side effect of Alpha-1 receptor activation?
What is a common side effect of Alpha-1 receptor activation?
- Hypotension
- Bronchoconstriction
- Hypertension (correct)
- Bradycardia
Which of the following effects is associated with Alpha-2 receptor agonists?
Which of the following effects is associated with Alpha-2 receptor agonists?
- Decreasing sympathetic outflow from CNS (correct)
- Vasodilation
- Increases heart rate
- Promotes mydriasis
Which agent is commonly used to delay the absorption of local anesthetics?
Which agent is commonly used to delay the absorption of local anesthetics?
What differentiates catecholamines from noncatecholamines regarding their metabolism?
What differentiates catecholamines from noncatecholamines regarding their metabolism?
Which statement regarding beta-1 agonists is true in the context of heart failure?
Which statement regarding beta-1 agonists is true in the context of heart failure?
What is the presynaptic receptor that provides negative feedback on NE release?
What is the presynaptic receptor that provides negative feedback on NE release?
What is the primary therapeutic use of beta-2 receptor agonists?
What is the primary therapeutic use of beta-2 receptor agonists?
What is the primary action of beta-2 agonists in the treatment of asthma?
What is the primary action of beta-2 agonists in the treatment of asthma?
Which beta-1 agonist adverse effect is particularly concerning for patients with coronary artery issues?
Which beta-1 agonist adverse effect is particularly concerning for patients with coronary artery issues?
What pharmacological role does epinephrine play in anaphylactic reactions?
What pharmacological role does epinephrine play in anaphylactic reactions?
What is a significant effect of beta-2 agonists at high doses?
What is a significant effect of beta-2 agonists at high doses?
Which agent is most commonly used to treat narcolepsy in children?
Which agent is most commonly used to treat narcolepsy in children?
What adverse effect is associated with alpha-2 agonists?
What adverse effect is associated with alpha-2 agonists?
What should be monitored when a patient is taking MAO inhibitors with tyramine?
What should be monitored when a patient is taking MAO inhibitors with tyramine?
In the treatment of glaucoma, which medication is used?
In the treatment of glaucoma, which medication is used?
Which of the following is a natural catecholamine?
Which of the following is a natural catecholamine?
What is the mode of action of non-catecholamines such as phenylephrine?
What is the mode of action of non-catecholamines such as phenylephrine?
Which adrenergic receptors does dobutamine primarily interact with?
Which adrenergic receptors does dobutamine primarily interact with?
What is a significant adverse effect associated with sympathomimetic drugs?
What is a significant adverse effect associated with sympathomimetic drugs?
Which drug is an example of a mixed-acting sympathomimetic agent?
Which drug is an example of a mixed-acting sympathomimetic agent?
Which chemical structure is characteristic of catecholamines?
Which chemical structure is characteristic of catecholamines?
Which sympathomimetic drug is primarily utilized as a beta-2 agonist?
Which sympathomimetic drug is primarily utilized as a beta-2 agonist?
How does reserpine affect the action of sympathomimetic drugs?
How does reserpine affect the action of sympathomimetic drugs?
Which of the following is a synthetic catecholamine?
Which of the following is a synthetic catecholamine?
Which sympathomimetic drug is known for its ability to enter the CNS?
Which sympathomimetic drug is known for its ability to enter the CNS?
Flashcards
Sympathomimetic Drugs
Sympathomimetic Drugs
Drugs that mimic effects of the sympathetic nervous system.
Catecholamines
Catecholamines
A class of sympathomimetics derived from tyrosine.
Natural Catecholamines
Natural Catecholamines
Catecholamines derived naturally, like epinephrine.
Synthetic Catecholamines
Synthetic Catecholamines
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Non-Catecholamines
Non-Catecholamines
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Directly Acting Sympathomimetics
Directly Acting Sympathomimetics
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Indirectly Acting Sympathomimetics
Indirectly Acting Sympathomimetics
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Mixed Action Sympathomimetics
Mixed Action Sympathomimetics
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Cocaine Effect
Cocaine Effect
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Reserpine Effect
Reserpine Effect
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Alpha-1 Receptors
Alpha-1 Receptors
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Alpha-2 Receptors
Alpha-2 Receptors
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Beta-1 Receptors
Beta-1 Receptors
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Beta-2 Receptors
Beta-2 Receptors
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Alpha-1 Therapeutic Use
Alpha-1 Therapeutic Use
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Beta-1 Therapeutic Use
Beta-1 Therapeutic Use
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Beta-2 Therapeutic Use
Beta-2 Therapeutic Use
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Alpha-1 Adverse Effects
Alpha-1 Adverse Effects
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Beta-1 Adverse Effects
Beta-1 Adverse Effects
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Amphetamine
Amphetamine
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Ephedrine
Ephedrine
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Tyramine
Tyramine
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Catecholamine Characteristics
Catecholamine Characteristics
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Non-Catecholamine Characteristics
Non-Catecholamine Characteristics
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Receptor Selectivity
Receptor Selectivity
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Study Notes
Sympathomimetic Drugs
- Sympathomimetic drugs, also known as adrenergic agonists, mimic the effects of the sympathetic nervous system.
- They can be classified based on their chemical structure (catecholamines or non-catecholamines) and their mode of action (direct or indirect).
- Catecholamines are derived from the amino acid tyrosine and include:
- Natural: epinephrine, norepinephrine, dopamine
- Synthetic: isoproterenol, dobutamine
- Non-catecholamines are not derived from tyrosine and include:
- Directly acting: methoxamine, phenylephrine, clonidine, terbutaline, oxymetazoline
- Indirectly acting: tyramine, mephentermine
- Mixed: ephedrine
Mode of Action
- Directly acting sympathomimetics bind to and activate adrenergic receptors.
- Indirectly acting sympathomimetics work by releasing stored norepinephrine (NE) from nerve terminals.
- Mixed action sympathomimetics have both direct and indirect actions.
Effects of Pre-Treatment with Cocaine or Reserpine
- Cocaine blocks the reuptake of NE, increasing its concentration in the synapse and enhancing the effects of directly acting sympathomimetics.
- It has no effect on indirectly acting sympathomimetics since they don't rely on NE reuptake.
- Reserpine depletes NE stores by inhibiting its storage in vesicles, thus reducing the effectiveness of both direct and indirect acting sympathomimetics.
Receptor Selectivity - Key Facts
- Alpha-1 receptors: Primarily located on blood vessels and cause vasoconstriction.
- Alpha-2 receptors: Found in the central nervous system (CNS) and suppress sympathetic outflow, leading to decreased blood pressure.
- Beta-1 receptors: primarily located in the heart and cause increased heart rate and contractility.
- Beta-2 receptors: located in the bronchioles, causing bronchodilation, and in the uterus, causing relaxation.
Therapeutic Uses of Sympathomimetics
- Alpha-1:
- Vasoconstriction: control superficial bleeding, decongestion, delay absorption of local anesthetics.
- Mydriasis: dilate pupils for ophthalmic procedures.
- Alpha-2:
- Antihypertensive: reduce blood pressure by decreasing sympathetic outflow.
- Beta-1:
- Inotropic effect: increase cardiac contractility in heart failure and shock.
- Increase conduction through the AV node in atrioventricular block.
- Restore cardiac rhythm after arrest.
- Beta-2:
- Bronchodilation: relieve bronchospasm in asthma.
- Inhibit uterine contractions: prevent preterm labor.
Adverse Effects
- Alpha-1: Hypertension, necrosis
- Alpha-2: Hypotension, withdrawal syndrome
- Beta-1: Tachycardia, arrhythmias, angina
- Beta-2: Hyperglycemia, tremors, tachycardia (at high doses)
Non-Catecholamine Sympathomimetics
- Amphetamine:
- Powerful CNS stimulant: used in ADHD and narcolepsy.
- Peripheral effects similar to NE, but with a longer duration of action due to resistance to metabolism.
- Ephedrine:
- Mixed action sympathomimetic acting both directly and indirectly.
- Weak CNS stimulant.
- Therapeutic use: bronchodilator.
- Tyramine:
- Found in certain foods and can cause hypertensive crises in patients taking MAO inhibitors (antidepressants).
- Pure indirect effect, releasing NE from vesicles.
Important Points
- Catecholamines have a shorter duration of action because they are readily metabolized by MAO and COMT.
- Non-catecholamines are less readily metabolized, allowing for longer effects.
- Catecholamines are highly polar and cannot easily cross the blood-brain barrier, limiting their CNS effects.
- Non-catecholamines are less polar and can enter the CNS.
- Receptor selectivity is never absolute, meaning that drugs may activate multiple receptor types at high doses.
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Description
This quiz covers sympathomimetic drugs, also known as adrenergic agonists, and their classification based on chemical structure and mode of action. Learn about catecholamines, non-catecholamines, and how these drugs interact with adrenergic receptors in the sympathetic nervous system.
