Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 38-23: Atropine & Anticholinergics Overdose + Key Features Download Section PDF Listen +++ ++ Antimuscarinic agents with variable CNS effects Atropine Scopolamine Belladonna Datura stramonium Hyoscyamus niger Some mushrooms Tricyclic antidepressants Antihistamines + Clinical Findings Download Section PDF Listen +++ ++ Anticholinergic syndrome Dryness of the mouth, thirst, difficulty swallowing, blurring of vision Dilated pupils, flushed skin, tachycardia, fever, delirium, myoclonus, ileus Antidepressants and antihistamines may induce convulsions Diphenhydramine commonly causes delirium, tachycardia, and seizures; massive overdose may mimic tricyclic antidepressant cardiotoxic poisoning Terfenadine and astemizole cause QT interval prolongation and torsades de pointes and were removed from US market + Diagnosis Download Section PDF Listen +++ ++ Based on history of ingestion, typical "anticholinergic syndrome" Serum levels not useful ECG monitoring for wide QRS, QT prolongation + Treatment Download Section PDF Listen +++ +++ Emergency and supportive measures ++ Activated charcoal Administer 60–100 g mixed in aqueous slurry orally or via gastric tube Do not use for comatose or convulsing patients unless they are intubated with a cuffed endotracheal tube External cooling and sedation, or neuromuscular paralysis in rare cases, are indicated to control high temperatures +++ Specific treatment ++ For severe anticholinergic syndrome, (eg, agitated delirium), Give physostigmine salicylate, 0.5–1 mg intravenously slowly over 5 minutes, with ECG monitoring Repeat as needed to total dose of no more than 2 mg Caution: Bradyarrhythmias and convulsions are a hazard with physostigmine administration, and the drug should not be used in patients with evidence of cardiotoxic effects (eg, QRS interval prolongation) from tricyclic antidepressants or other sodium channel blockers