Pharmacology Quiz on Adrenergic Receptors
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Questions and Answers

What primary effect does stimulation of β1-adrenergic receptors have on the cardiovascular system?

  • Vasodilation of peripheral blood vessels
  • Decreased heart rate and cardiac output
  • Bronchodilation and decreased airway resistance
  • Increased stroke volume and heart rate (correct)

    • What is a common adverse effect of sympathomimetic drugs acting on β2-adrenergic receptors?

  • Skeletal muscle tremors (correct)
  • Hypotension
  • Cerebral hemorrhage
  • Bradycardia

    • Which adrenaline-related condition can result from excessive use of α-adrenergic receptor agonists?

  • Acute bronchial asthma
  • Acute insulin hypoglycemia
  • Gangrene in extremities (correct)
  • Urticaria

    • Why should noradrenaline be closely monitored during infusion?

    <p>It may result in severe hypertension if stopped abruptly</p> Signup and view all the answers

    What complication can arise from the interaction of non-selective beta blockers with sympathomimetics?

    <p>Severe hypertension and hyperkalemia</p> Signup and view all the answers

    In what condition is noradrenaline most appropriately used?

    <p>Acute hypotension during spinal anesthesia</p> Signup and view all the answers

    What adverse effect is specifically associated with isoprenaline?

    <p>Increased incidence of cardiac arrhythmias</p> Signup and view all the answers

    What serious condition can occur if extravasation of noradrenaline happens during administration?

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

    What is the primary pharmacological effect of stimulation of β2 receptors in the respiratory system?

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

    Which of the following best describes the result of α1 receptor stimulation in the gastrointestinal tract?

    <p>Contraction of sphincters</p> Signup and view all the answers

    In the context of treating anaphylactic shock, what is the primary benefit of using adrenaline?

    <p>Its effects as a physiological antagonist of histamine</p> Signup and view all the answers

    What common adverse effect might a patient experience with excessive adrenaline administration due to CNS stimulation?

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

    Which mechanism does β1 receptor stimulation NOT influence?

    <p>Increased glucose uptake by muscle</p> Signup and view all the answers

    How does adrenaline facilitate aqueous humor dynamics in the eye?

    <p>Decreases aqueous humor production via α1 receptors</p> Signup and view all the answers

    Which condition is most appropriately treated with β2 agonists?

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

    What is a notable interaction when using sympathomimetics like adrenaline?

    <p>Potentially increased risk of hypertensive crisis with certain MAO inhibitors</p> Signup and view all the answers

    What is the primary action of beta-1 adrenergic receptors?

    <p>Cardiac stimulation</p> Signup and view all the answers

    Which adverse effect is commonly associated with the use of sympathomimetics?

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

    Which of the following is NOT a pharmacological use of catecholamines?

    <p>Inducing sedation</p> Signup and view all the answers

    What is one of the primary uses of beta-2 adrenergic receptor stimulation?

    <p>Promoting bronchodilation</p> Signup and view all the answers

    Which drug is an agonist at the beta-1 adrenergic receptor?

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

    In which condition would sympathomimetics typically be contraindicated?

    <p>Cardiac arrhythmias</p> Signup and view all the answers

    Which of the following correctly describes the method of action for alpha-2 adrenergic receptors?

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

    Which statement accurately reflects the pharmacokinetics of adrenaline?

    <p>Adrenaline is poorly absorbed when given orally.</p> Signup and view all the answers

    Study Notes

    Credit Hours

    • Tanta Medical Program
    • Credit-Hours

    Sympathomimetics

    • Objectives (ILOs):
      • Recognize catecholamine synthesis, storage, and release.
      • Identify different types of adrenergic receptors and their functions.
      • Recognize sympathomimetics (action, uses, side effects, and contraindications).
    • Autonomic Nervous System Overview:
      • Diagram showing the relationship between the nervous system, preph, somatic, and ANS.
      • Diagram showing the relationship between sympathetic and parasympathetic systems.

    Adrenergic Neuronal Transmission

    • Diagrams illustrating the process, including:
      • Tyrosine, Dopa, Dopamine, Norepinephrine (NE) synthesis.
      • Storage, release (exocytosis), and reuptake.
      • Metabolism by MAO and COMT.
      • Interaction with alpha and beta receptors.

    Catecholamine Fate

    • Neuronal uptake—major part.
    • Granular uptake (vesicular uptake).
    • Metabolism by specific enzymes (MAO-COMT).
    • Stimulation of presynaptic alpha adrenoreceptors.

    Alpha & Beta Adrenoreceptors

    • Classification of receptors: alpha1, alpha2, beta1, beta2, and beta3.

    • Mechanism of action for each receptor type. Include diagrams

    • Alpha1 Receptors (post):

      • Contraction of erector pilae muscle.
      • Mydriasis.
      • Vasoconstriction.
      • Other functions.

    • Alpha2 Receptors (pre-post-CNS):

      • Inhibitory effects. and other functions.

    • Beta1 Receptors:

      • C.N.S stimulation.
      • Cardiac stimulation.
      • Increase renin release.
      • Lipolysis and free fatty acid.

    • Beta2 Receptors:

      • Generalized vasodilatation (VD).
      • Bronchodilatation. -Stimulate insulin release.
      • Glycogenolysis in liver and skeletal muscles.
      • Relax G.I.T. and bladder.
      • Relax the uterus.
      • Skeletal muscle tremors

    • Beta3 Receptors: -Fat cells-lipolysis

    Alpha Adrenoreceptors (α1) (post)

    • Agonist: phenylephrine
    • Antagonist: prazosin
    • Physiological effects.

    Alpha Adrenoreceptors (α2) (pre-post-CNS)

    • Agonist: clonidine
    • Antagonist: yohimbine
    • Physiological effects

    Adrenaline (Epinephrine)

    • Sympathomimetic catecholamine present in the adrenal medulla and CNS.
    • Prepared in dark brown ampoules due to instability in alkaline environments.
    • Stored in acid medium.

    Adrenaline (Epinephrine) Kinetics

    • Not absorbed orally, not taken IV or IM.
    • All catecholamines do not pass BBB.
    • Fate: Nerve and tissue reuptake, metabolism by MAO and COMT.
    • Excreted unchanged in urine (2%).

    Adrenaline (Epinephrine) Dynamics

    • Mechanism of action: Stimulates all adrenergic receptors (alpha 1&2-beta 1&2&3).
    • Pharmacological effects: Local and Systemic.

    Adrenaline (Epinephrine) Pharmacological Effects

    • Local:
      • Skin: vasoconstriction
      • Mucous membrane: vasoconstriction, decongestion.
      • Eye: vasoconstriction; no mydriasis with adrenaline
      • Effect on aqueous humor dynamics.
      • Bronchi: decongestion; bronchodilation
    • Systemic:
      • C.N.S.: Mild stimulation ⇒ anxiety
      • Eye: Stimulation of dilator papillae muscle ⇒ mydriasis.
      • Cardiovascular system:
      • Heart: Increase all cardiac properties.-Blood vessels: V.C of skin mucous and renal blood vessels (a1). V.D of skeletal muscle and coronary blood vessels (B2).
      • Increase blood pressure: COPXPR.
      • Adrenaline reversal to lower BP.
      • Respiratory system
        • Decongestion of bronchial mucosa,bronchodilation.
      • Gastrointestinal Tract
        • Constriction of sphincters
        • relaxation of intestinal wall
      • Urinary bladder
        • Bladder sphincter constricted, urinary wall relaxed.
      • Uterus: Early pregnancy: uterine contraction; Late pregnancy, relaxation.
      • Skeletal muscles
      • Anti-allergic effect
      • Metabolism carbohydrates/glycogenolysis: hyperglycaemia
      • Metabolism lipid/lipolysis: increase in plasma fatty acid
      • Other effects Transient hyperkalaemia

    Adrenaline (Epinephrine) Uses

    • Local: Open-angle glaucoma, haemostatic nasal pack in epistaxis, with local anesthesia ( ↑Duration &↓systemic toxicity and bleeding).
    • Systemic: Anaphylactic shock, acute bronchial asthma, acute insulin hypoglycemia, cardiac resuscitation, contracting uterus during labor.

    Adrenaline (Epinephrine) Adverse Effects

    • CNS: anxiety, headache
    • α effects: Gangrene (injection around finger/toe) ;hypertension, cerebral hemorrhage
    • β1 effects: Tachycardia, palpitation, angina, arrhythmia
    • β2 effects: Skeletal muscle tremors

    Adrenaline (Epinephrine) Contraindications and Drug Interactions

    • Around finger/toes → Gangrene
    • Hypertension
    • Hemorrhagic shock ( Hemorrhage → hypovolemia → hypotension → reflex V.C. → renal V.C → renal failure →death).
    • Other contraindications and interactions.

    Noradrenaline (Norepinephrine)

    • Natural sympathomimetic catecholamine
    • IV infusion only
    • Not orally, does not pass BBB
    • Similar fate to adrenaline.

    Noradrenaline (Norepinephrine) Dynamics

    • Mechanism of action: Very effective α-adrenergic receptor agonist, limited β2-adrenergic receptor activity.

    Noradrenaline (Norepinephrine) Pharmacological Effects

    • C.V.S.: Generalized vasoconstriction (except coronary).
    • Blood pressure: Increase (COPX↑PR).
    • Bradycardia.
    • ↑Stroke volume.
    • ↑ Excitability and automaticity (arrhythmia).

    Noradrenaline (Norepinephrine) Uses

    • Acute hypotension (spinal anesthesia, post-operative shock).
    • Added to local anesthetics.

    Noradrenaline (Norepinephrine) Adverse Effects

    • Necrosis and gangrene (extravasation).
    • Hypertension → cerebral hemorrhage.
    • Reflex bradycardia.
    • Headache and anxiety.

    Isoprenaline (Isoproterenol)

    • Synthetic sympathomimetic catecholamine.
    • Non-selective β agonist.
    • Used in acute heart block, and acute bronchial asthma.
    • Main adverse effects: Tachycardia, angina, and arrhythmia.

    Dopamine

    • Natural sympathomimetic catecholamine.
    • Mechanism of action: Stimulates dopaminergic, α, and β receptors.
    • Dopaminergic receptors:
      • D1: Peripheral effects.
      • D2: Central effects.
      • D3: Decreases dopamine release (presynaptic autoreceptor).

    Dopamine Peripheral Effects

    • Small dose: D1 → ↑Renal blood flow (RBF).
    • Moderate dose: D1 + β1 effects.
    • Large dose: α1 → ↑Peripheral resistance (PR).
    • Other effects.

    Dopamine Central Effects

    • Limbic system: Euphoria, psychosis.
    • Basal ganglia: Anti-parkinsonism.
    • Hypothalamus: Pyrexia, appetite, prolactin suppression
    • C.T.Z.: nausea, vomiting

    Dopamine Uses

    • Shock: Positive inotropic, improves microcirculation and increases renal blood flow (restore blood volume).
    • Resistant heart failure

    Dopamine Side Effects

    • Tachycardia and arrhythmia.
    • Nausea and vomiting.

    Dobutamine

    • Selective β1 agonist.
    • Positive inotropic and dromotropic effects.
    • Minimal tachycardia and change in peripheral resistance.
    • Used in cardiogenic shock, resistant HF.

    Fenoldopam

    • Direct selective D1 agonist.
    • Vasodilation.
    • Decrease in total peripheral resistance and blood pressure.

    Alpha-Stimulants (1-VASOPRESSORS)

    • Stimulation of α1-receptors⇒vasoconstriction.
    • Increase in total peripheral resistance (TPR) & blood pressure (BP) used to treat hypotension.
    • Examples: Norepinephrine, Ephedrine, Phenylephrine, Midodrine.

    Alpha-Stimulants Uses

    • Local: Nasal decongestion, open-angle glaucoma.
    • Systemic: Hypotension, end attack of paroxysmal atrial tachycardia.

    Alpha-Stimulants Adverse Effects

    • Hypertension, reflex bradycardia.

    2-Nasal Decongestants

    • Alpha1 agonists on topical application → local vasoconstriction of nasal mucosa.
    • Longer duration of action (12 hours) than ephedrine.
    • Used for allergic rhinitis & common cold.
    • Side effects: Orally → hypertension, chronic use → atrophic rhinitis, repeated local administration → severe rebound congestion

    Ephedrine

    • Primarily acts indirectly, with some direct action on α and β receptors.
    • Similar effects to adrenaline, but weaker, slower onset, longer duration, and tachyphylaxis.

    Assignment Questions

    • A patient receiving penicillin intravenous developed anaphylactic shock, what drugs can be used?
      • Norepinephrine, Epinephrine, Phenylephrine, Dobutamine.
    • Prazosin before noradrenaline administration can result in?
      • Sustained hypertension, Hypotension, abolish hypertension, No effect
    • Reflex bradycardia induced by noradrenaline can be blocked by?
      • Dopamine, Isoprenaline, Atropine, Ephedrine

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    Description

    Test your knowledge on the effects and complications of adrenergic receptors in pharmacology. This quiz addresses key concepts related to β1 and β2-adrenergic stimulation, potential adverse effects, and appropriate clinical applications of drugs like noradrenaline. Challenge yourself to understand the systemic impacts of these medications.

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