Therapeutic Actions for Muscarinic Antagonists

Organ System
Application and Comments
Atropine, homatropine, tropicamide

Eye and Cardiac

• Causes mydriasis and cycloplegia
• Used for ophthalmologic exams
• Can be used for post-MI bradyarrythmias 
Benztropine  CNS • Parkinson's disease
Scopolamine  CNS • Motion sickness
• Fast onset
Ipratropium Respiratory • Asthma
• Tiotropium produces a longer bronchodilator effect
• Relief of rhinorrhea with common cold, allergic and nonallergic rhinitis
Oxybutynin, trospium, glycopyrrolate Genitourinary • Reduce urgency in mild cystitis
• Reduce bladder spasms after urologic surgery
Methscopolamine, pirenzepine, propantheline Gastrointestinal • Peptic ulcer treatment


  • Muscarinic antagonist
    • blocks effects of cholinesterase inhibitor poisoning
  • Organ system
    • eye: ↑ pupil dilation and cycloplegia
    • lungs: ↓ secretions
    • GI and GU: ↓ stomach acid secretion, ↓ gut motility, and ↓ urgency in cystitis
  • Toxicity
    • CNS: ↑ body temperature, disorientation, hyperthermia in infants
    • Cardiovascular: tachycardia and flushing
    • Dermatologic: anhidrosis and urticaria
    • GI and GU: dry mouth, constipation, urinary retention 
    • Ocular: cycloplegia, acute angle-closure glaucoma, dry eyes
  • The atropine adage: "hot as a hare, dry as a bone, red as a beet, blind as a bat, mad as a hatter, the bowel and bladder loser their tone, and the heart runs alone" 

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