BMS161 Cholinergic Pharmacology: Antimuscarinic
24 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a common complication of enlarged prostate in older patients?

  • Iridocyclitis
  • Atropine toxicity
  • Constipation
  • Urine retention (correct)
  • Which of the following is NOT a pre-anesthetic medication use of Atropine?

  • Antiemetic
  • Stimulate R.C.
  • Mydriatic (correct)
  • Bronchodilation
  • What is the advantage of Hyoscine (Scopolamine) over Atropine in thyrotoxicosis and cardiac patients?

  • Less risk of arrhythmia (correct)
  • Longer acting
  • More effective in motion sickness
  • More CNS depressant action
  • Which drug is used to treat tremors or antipsychotic-induced Parkinson's disease?

    <p>Benztropine-Benzhexol</p> Signup and view all the answers

    What is the disadvantage of using Hyoscine (Scopolamine) in females?

    <p>Induces CNS excitement and hallucination</p> Signup and view all the answers

    Which mydriatic cycloplegic is shorter acting and easier to reverse, except in children?

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

    What is the disadvantage of using Ipratropium as a bronchial atropine substitute?

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

    Which of the following is a characteristic of Tiotropium, a bronchial atropine substitute?

    <p>Selective M3 blocker</p> Signup and view all the answers

    What is the primary reason for using antisecretory antispasmodics before neostigmine?

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

    Which of the following drugs is used in urinary atropine substitutes?

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

    What is the indication for using atropine in organophosphate poisoning?

    <p>To treat mushroom poisoning</p> Signup and view all the answers

    Which of the following antiarrhythmics has atropine-like action?

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

    What is the mechanism of action of dicyclomine?

    <p>Selective M1 blocker</p> Signup and view all the answers

    What is the indication for using atropine in pre-anesthetic medication?

    <p>To reduce salivary secretion</p> Signup and view all the answers

    Which of the following drugs is used in irritable bowel syndrome?

    <p>Hyoscine butylbromide</p> Signup and view all the answers

    What is the effect of antisecretory antispasmodics on the absorption of Competitive Muscle Blockers?

    <p>Decrease the absorption</p> Signup and view all the answers

    What is the primary mechanism of atropine's antiemetic effect?

    <p>Blockage of M receptors in the vomiting center</p> Signup and view all the answers

    What is the effect of atropine on aqueous outflow in the eye?

    <p>Decreased outflow, increasing IOP</p> Signup and view all the answers

    Which autonomic receptor subtype is responsible for atropine's effect on blood pressure?

    <p>None of the above</p> Signup and view all the answers

    What is the effect of atropine on salivation?

    <p>Decreased salivation</p> Signup and view all the answers

    What is the therapeutic use of atropine in the CNS?

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

    What is the contraindication for atropine use in patients with glaucoma?

    <p>Narrow anterior chamber</p> Signup and view all the answers

    What is the effect of atropine on bronchial secretions?

    <p>Decreased bronchial secretions</p> Signup and view all the answers

    What is the effect of atropine on body temperature?

    <p>Increased body temperature</p> Signup and view all the answers

    Study Notes

    Antimuscarinic Pharmacology

    • Antimuscarinics are competitive antagonists of acetylcholine (Ach) at muscarinic (M) receptors.

    Effects of Atropine

    CNS

    • Stimulation of respiratory center
    • Antiemetic effects by blocking M receptors in vomiting center
    • Antiparkinsonian effects
    • Eye effects:
      • Passive mydriasis (paralysis of constrictor)
      • Cycloplegia (loss of accommodation)
      • Increased intraocular pressure (IOP) → acute glaucoma in narrow chamber

    CVS

    • Tachycardia and increased AVN conduction
    • No effect on blood pressure (M3 has no role in regulating blood pressure)
    • Vasodilation (histamine release in toxic dose)

    Smooth Muscle

    • Decreased salivation (dry mouth)
    • Decreased lacrimation (dry, sandy eyes)
    • Bronchodilation
    • Decreased sweating (increased body temperature)
    • Decreased gastric secretion (least affected)
    • Urinary retention
    • Decreased bronchial secretions

    Adverse Effects and Contraindications

    • Confusion, restlessness, hallucinations, delirium, and mania
    • Blurred vision and photophobia
    • Acute glaucoma in patients with narrow anterior chamber (contraindication)
    • Dry mouth and skin
    • Hyperthermia (complete skin dryness)
    • Vasodilation and flushing
    • Tachycardia
    • Urine retention in old patients with enlarged prostate (contraindication)
    • Constipation

    Atropine Toxicity and Treatment

    • Treatment:
      • Physostigmine
      • Diazepam
      • Cooling blankets

    Clinical Uses of Atropine and Atropine Substitutes

    Pre-anesthetic Medication

    • Decreased salivary and bronchial secretion
    • Anti-emetic effects
    • Bronchodilation
    • Stimulation of respiratory center
    • Decreased severe vagal bradycardia in anesthesia

    Hyoscine (Scopolamine)

    • Mydriatic (briefer than atropine)
    • More safe in thyrotoxicosis and cardiac patients (less risk of arrhythmia)
    • More CNS depressant action → drowsiness and amnesia
    • Disadvantage: May induce CNS excitement and hallucination in females → vivid dreams

    Antiparkinson (PD)

    • Drug used: Benztropine (Benzhexol)
    • Used for tremors or antipsychotic-induced PD

    Vomiting of Motion Sickness and Minieres Disease

    • Drug used: Hyoscine (more effective than atropine)

    Mydriatic Cycloplegics

    • Drugs used: Cyclopentolate, tropicamide, and homatropine
    • Advantages: shorter-acting and easier to reverse (except in children)
    • Uses:
      • Iridocyclitis
      • Measuring refractive errors
      • Fundus examination

    Bronchial Atropine Substitutes

    • Advantages: 4ry amines given by inhalation with no systemic effect and not drying secretions
    • Used in asthma and COPD: delayed onset
    • Drugs used:
      • Ipratropium (M2/M3 blocker)
      • Tiotropium (selective M3 blocker)
    • Longer-acting with no tolerance

    Antisecretory Antispasmodics

    • Used before neostigmine to decrease its side effects (bradycardia, bronchospasm) during reversal of action of competitive muscle blockers
    • Drugs used:
      • Glycopyrrolate
      • Hyoscine butylbromide
      • 3ry drugs: Dicyclomine (selective M1 blocker in Myenteric plexus) → antispasmodic

    Urinary Atropine Substitutes

    • Used in nocturnal enuresis and in urge incontinence and overactive bladder
    • Drugs used:
      • Oxybutynin
      • Darifenacin
      • Solifenacin
      • Tolterodine
      • Trospium
      • Emepronium

    Atropine Still Used In:

    • CVS:
      • Hyperactive carotid sinus
      • Heart block (AV block)
      • Bradycardia (in infarction or digitalis toxicity)
    • Organophosphate poisoning
    • Mushroom poisoning (Amanita muscaria)
    • Cycloplegic in children
    • Pre-anesthetic medication

    Drugs with Atropine-Like Action

    • Additive atropine effects:
      • Antiarrhythmics: quinidine, procainamide, and disopyramide
      • Antihistamines (1st generation)
      • Tricyclic antidepressants, antipsychotics, and pethidine

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    This lecture covers the classification and differentiation of antimuscarinic agents, their specificity to organs, and key points of pharmacology. Learn about cholinergic pharmacology with this lecture from the Faculty of Medicine.

    More Like This

    Cholinergic Pharmacology Quiz
    10 questions
    tema 9
    10 questions

    tema 9

    RegalHolmium avatar
    RegalHolmium
    Cholinergic Antagonists Overview
    36 questions
    Use Quizgecko on...
    Browser
    Browser