Antimuscarinics Flashcards
Antimuscarinic Agents
Atropine, Glycopyrrolate, and Scopolamine
Antimuscarinic MOA
Competitive antagonists of acetylcholine at muscarinic receptors (blocks Ach from binding)
Antimuscarinic Sites of Action
Antimuscarinics act at peripheral tissues innervated by parasympathetic postganglionic nerves
Of note, atropine and scopolamine are tertiary amines and can cross the blood-brain barrier, therefor they have actions at sites of cholinergic transmission in the central nervous system
Antimuscarinic Effects (7)
Unopposed sympathetic response
Mydriasis
Blurred vision
Tachycardia (increased AV conduction)
Decreased secretions
Bronchodilation
Decreased tone and motility (“weakening”) of lower esophageal sphincter
Decreased bladder tone
Atropine Class
Antimuscarinic (tertiary amine)
Atropine Dosing
With edrophonium: 7 mcg/kg
Non-symptomatic bradycardia: titrate to effect with small incremental doses
Symptomatic bradycardia in ACLS: 0.5 mg bolus, 3 mg maximum
Atropine Onset and DOA
Onset: 1 minutes
DOA: 1 hours
Atropine Metabolism
Liver
Atropine Excretion
Renally and hepatically eliminated
Atropine and Scopolamine Admin Considerations
Risk for CNS anticholinergic syndrome
Glycopyrrolate Class
Antimuscarinic (quaternary ammonium)
Glycopyrrolate Dosing
With neostigmine: 0.2 mg of glycopyrrolate for every 1 mg of neostigmine
(Glycopyrrolate concentration: 0.2 mg/mL
Neostigmine concentration: 1 mg/mL
Therefore: 1 mL of glycopyrrolate per 1 mL of neostigmine)
Non-symptomatic bradycardia: titrate to effect with small incremental doses of 0.1-0.2 mg
Glycopyrrolate Onset and DOA
Onset: 2 minutes
DOA: 2 hours
Glycopyrrolate Metabolism
A portion is metabolized by the liver
Glycopyrrolate Excretion
A larger portion renally eliminated unchanged
