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Questions and Answers
What is a common complication of enlarged prostate in older patients?
What is a common complication of enlarged prostate in older patients?
Which of the following is NOT a pre-anesthetic medication use of Atropine?
Which of the following is NOT a pre-anesthetic medication use of Atropine?
What is the advantage of Hyoscine (Scopolamine) over Atropine in thyrotoxicosis and cardiac patients?
What is the advantage of Hyoscine (Scopolamine) over Atropine in thyrotoxicosis and cardiac patients?
Which drug is used to treat tremors or antipsychotic-induced Parkinson's disease?
Which drug is used to treat tremors or antipsychotic-induced Parkinson's disease?
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What is the disadvantage of using Hyoscine (Scopolamine) in females?
What is the disadvantage of using Hyoscine (Scopolamine) in females?
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Which mydriatic cycloplegic is shorter acting and easier to reverse, except in children?
Which mydriatic cycloplegic is shorter acting and easier to reverse, except in children?
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What is the disadvantage of using Ipratropium as a bronchial atropine substitute?
What is the disadvantage of using Ipratropium as a bronchial atropine substitute?
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Which of the following is a characteristic of Tiotropium, a bronchial atropine substitute?
Which of the following is a characteristic of Tiotropium, a bronchial atropine substitute?
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What is the primary reason for using antisecretory antispasmodics before neostigmine?
What is the primary reason for using antisecretory antispasmodics before neostigmine?
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Which of the following drugs is used in urinary atropine substitutes?
Which of the following drugs is used in urinary atropine substitutes?
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What is the indication for using atropine in organophosphate poisoning?
What is the indication for using atropine in organophosphate poisoning?
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Which of the following antiarrhythmics has atropine-like action?
Which of the following antiarrhythmics has atropine-like action?
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What is the mechanism of action of dicyclomine?
What is the mechanism of action of dicyclomine?
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What is the indication for using atropine in pre-anesthetic medication?
What is the indication for using atropine in pre-anesthetic medication?
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Which of the following drugs is used in irritable bowel syndrome?
Which of the following drugs is used in irritable bowel syndrome?
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What is the effect of antisecretory antispasmodics on the absorption of Competitive Muscle Blockers?
What is the effect of antisecretory antispasmodics on the absorption of Competitive Muscle Blockers?
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What is the primary mechanism of atropine's antiemetic effect?
What is the primary mechanism of atropine's antiemetic effect?
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What is the effect of atropine on aqueous outflow in the eye?
What is the effect of atropine on aqueous outflow in the eye?
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Which autonomic receptor subtype is responsible for atropine's effect on blood pressure?
Which autonomic receptor subtype is responsible for atropine's effect on blood pressure?
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What is the effect of atropine on salivation?
What is the effect of atropine on salivation?
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What is the therapeutic use of atropine in the CNS?
What is the therapeutic use of atropine in the CNS?
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What is the contraindication for atropine use in patients with glaucoma?
What is the contraindication for atropine use in patients with glaucoma?
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What is the effect of atropine on bronchial secretions?
What is the effect of atropine on bronchial secretions?
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What is the effect of atropine on body temperature?
What is the effect of atropine on body temperature?
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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
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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.