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Questions and Answers
What are the different types of adrenergic agents mentioned in the content?
What are the different types of adrenergic agents mentioned in the content?
Adrenopositive agents and Adrenonegative agents
Which adrenergic receptor does Epinephrine primarily act on?
Which adrenergic receptor does Epinephrine primarily act on?
Norepinephrine, Epinephrine, and Isoprenaline are examples of __________.
Norepinephrine, Epinephrine, and Isoprenaline are examples of __________.
Catecholamines
Epinephrine causes bronchodilation.
Epinephrine causes bronchodilation.
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What effect does Isoprenaline have on Mean Blood Pressure (MBP)?
What effect does Isoprenaline have on Mean Blood Pressure (MBP)?
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What effect does Epinephrine have on Systolic Blood Pressure (SBP) in a dose-dependent manner?
What effect does Epinephrine have on Systolic Blood Pressure (SBP) in a dose-dependent manner?
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Phenylephrine causes vasoconstriction in nasal mucosa as a ____________ action vasoconstrictor.
Phenylephrine causes vasoconstriction in nasal mucosa as a ____________ action vasoconstrictor.
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Selective alpha 2 adrenoreceptor agonists can have a very fast-acting hypotensive effect.
Selective alpha 2 adrenoreceptor agonists can have a very fast-acting hypotensive effect.
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Match the following clinical uses with the respective drug:
- Acute rhinitis, nose bleeding, paroxysmal ventricular tachycardia
- Coronary artery disease, tachycardia, thyrotoxicosis
- Glaucoma
Match the following clinical uses with the respective drug:
- Acute rhinitis, nose bleeding, paroxysmal ventricular tachycardia
- Coronary artery disease, tachycardia, thyrotoxicosis
- Glaucoma
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What is the clinical use of carvedilol?
What is the clinical use of carvedilol?
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What is the mechanism of toxicity of beta blockers?
What is the mechanism of toxicity of beta blockers?
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Central nervous system toxicity, including convulsions and coma, is commonly seen with beta blockers.
Central nervous system toxicity, including convulsions and coma, is commonly seen with beta blockers.
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Beta blockers may cause ____, hypotension, and bradycardia as cardiac disturbances in poisoning.
Beta blockers may cause ____, hypotension, and bradycardia as cardiac disturbances in poisoning.
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Match the following toxicology treatment with their associated actions:
Match the following toxicology treatment with their associated actions:
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Study Notes
Adrenopositive Agents
- Adrenopositive agents are also known as adrenomimetic or sympathomimetic agents
- Examples include Epinephrine, Isoprenaline, Norepinephrine, and Clonidine
- These agents stimulate adrenergic receptors, leading to various physiological effects
Alpha 1 Adrenergic Receptors
- Found in smooth muscle, especially in blood vessels, eyes, and urinary bladder
- Stimulation leads to:
- Contraction of smooth muscle in blood vessels, eyes, and urinary bladder
- Vasoconstriction, increasing diastolic blood pressure and heart preload
- Mydriasis, increasing intraocular pressure
Alpha 2 Adrenergic Receptors
- Found in pancreatic beta cells, nerve endings, and eyes
- Stimulation leads to:
- Decreased insulin secretion from pancreatic beta cells
- Decreased norepinephrine release from nerve endings
- Decreased intraocular fluid secretion from eyes
Beta 1 Adrenergic Receptors
- Found in heart, kidneys, and adipose tissue
- Stimulation leads to:
- Increased heart rate and contractility
- Increased conduction velocity in the heart
- Increased renin release from kidneys
- Lipolysis in adipose tissue
Beta 2 Adrenergic Receptors
- Found in smooth muscle, especially in lungs, blood vessels, and uterus
- Stimulation leads to:
- Relaxation of smooth muscle in lungs, blood vessels, and uterus
- Bronchodilation, decreasing airway resistance
- Vasodilation, decreasing diastolic blood pressure and heart preload
- Tocolytic effect, inhibiting uterine contractions
Adrenonegative Agents
- Adrenonegative agents are also known as adrenergic blockers or sympatholytics
- Examples include Propranolol, Doxazosin, and Clonidine
- These agents block adrenergic receptors, leading to various physiological effects
Alpha 1 Adrenoreceptor Antagonists
- Examples include Doxazosin and Prazosin
- Clinical use: treatment of hypertension and symptoms of benign prostatic hyperplasia
Beta Adrenoreceptor Antagonists (BAB)
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Examples include Propranolol and Metoprolol
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Clinical use: treatment of hypertension, angina pectoris, cardiac arrhythmias, and thyrotoxicosis
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Side effects: bradycardia, decreased exercise tolerance, and rebound effect upon sudden withdrawal### Beta Adrenoreceptor Antagonists
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Nonselective beta blockers (BAB) may mask initial symptoms of insulin overdose, including tachycardia, tremor, and anxiety.
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Cardioselective BAB are safer for patients with diabetes mellitus (DM).
Side Effects and Interactions
- Side effects of BAB include bradycardia, AV block, risk of bronchial obstruction, sexual dysfunction, and Raynaud syndrome.
- Interactions: Non-selective action may affect the effects of adrenopositive agents.
Nonselective Beta Adrenoreceptor Antagonists
- Examples: Timolol eye drops, which reduce intraocular fluid secretion in the ciliary body and decrease intraocular pressure.
- Clinical use: Glaucoma.
- Target structures in the eye: three muscles (pupil dilator, pupil constrictor muscle, ciliary muscle) and ciliary body epithelium.
Selective Beta 1 Adrenoreceptor Antagonists
- Examples: Metoprolol, Bisoprolol, which are highly selective β1 adrenoblockers.
- Clinical use: Coronary artery disease (CAD), hypertension, atrial fibrillation, chronic heart failure (CHF), and prophylaxis of migraine attacks.
- Lipophilic BAB cause vasoconstriction.
- Cardioslectivity β1: less impact on β/vascular smooth muscle, bronchi, uterus, and electrolyte balance (lower risk of hyperkalemia).
Selective Alpha 1, Nonselective Beta Adrenoreceptor Antagonists
- Examples: Carvedilol, which has cardiodepressant and antioxidant properties, and reduces peripheral vascular resistance.
- Clinical use: Chronic heart failure, CAD, and hypertension.
- BAB effect on renin is not clinically important, as it will compensate.
Raynaud Syndrome
- Characterized by episodic stenosis of limb arteries and arterioles, usually provoked by cold or stress.
- Manifested as sudden paleness or cyanosis of the fingers and toes, including the earlobe and nose.
- β2 blockage causes peripheral vasoconstriction, leading to limb freezing.
Beta Adrenoreceptor Antagonist Toxicology
- Mechanism of toxicity: All beta blockers antagonize beta1 adrenoreceptors, decreasing heart rate and cardiac contractility.
- Nonselective beta blockers also antagonize beta2 receptors, leading to bronchoconstriction, hypoglycemia, and hyperkalemia.
Clinical Presentation
- Cardiac disturbances: first-degree heart block, hypotension, and bradycardia.
- Central nervous system toxicity: convulsions, coma, and respiratory arrest.
- Bronchospasm: most common in patients with preexisting asthma or chronic bronchospastic disease.
- Hypoglycemia and hyperkalemia may occur.
Treatment
- Emergency and supportive measures: maintain an open airway, assist ventilation, and treat coma, seizures, hypotension, hyperkalemia, and hypoglycemia.
- Specific drugs and antidotes: glucagon, calcium chloride, high-dose insulin euglycemic therapy, sodium bicarbonate, and vasopressors.
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Description
Quiz about adrenergic agents, including selective and nonselective agonists, and their effects on the autonomic nervous system.
