Anticholinergic Drugs

Atropine

Dosage

• Premedication (antisialagogue effect): intravenous (IV) or intramuscular (IM) 0.01 to 0.02 mg/kg up to the usual adult dose of 0.4 to 0.6 mg

• Severe bradycardia: Larger IV doses up to 2 mg may be required

Clinical Considerations

• Most efficacious anticholinergic for bradyarrhythmias

• Patients with coronary artery disease may not tolerate the increased myocardial oxygen demand or decreased oxygen supply associated with atropine-induced tachycardia

• Ipratropium bromide solution (0.5 mg in 2.5 mL) is a derivative of atropine; metered-dose inhibitor treatment of bronchospasm; particularly effective in acute COPD when combined with a β-agonist (i.e., albuterol)

• Rapidly crosses the BBB; central nervous system (CNS) effects are minimal at usual doses, although toxic doses are typically associated with excitatory reactions

• Associated with mild postoperative memory deficits

• Cautious use in narrow-angle glaucoma, prostatic hypertrophy, and bladder-neck obstruction

Scopolamine

Dosage

• Premedication (antisialagogue effect): usually given IM 0.01 to 0.02 mg/kg up to the usual adult dose of 0.4 to 0.6 mg

• Scopolamine hydrobromide solutions available as 0.3, 0.4, and 1 mg/mL

Clinical Considerations

• More potent antisialagogue than atropine

• Greater CNS effects: drowsiness, amnesia, (restlessness and delirium possible); sedative effects may be useful as premedication; may interfere with awakening after short procedures

• Prevention of motion sickness: lipid solubility allows transdermal absorption

• Avoid in patients with closed-angle glaucoma

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