Medication and PharmacologyMedication Dosing and Pharmacology
Cholinergic Toxidrome
Medication-focused toxicology response with antidote use and dosing-focused treatment priorities.
Query: How do I recognize and treat a cholinergic toxidrome?
Summary
In a cholinergic toxidrome, patients typically present with signs of muscarinic excess – the classic “SLUDGE” picture (Salivation, Lacrimation, Urination, Defecation, Gastrointestinal upset, Emesis) – as well as nicotinic findings such as muscle fasciculations and weakness. Other key findings include miosis, bronchorrhea leading to respiratory compromise, and potentially seizures or altered mental status. Recognizing these findings is essential to guide prompt antidotal therapy alongside supportive care 52.
- Dose (Atropine): 0.02 mg/kg IV bolus (start low, double the dose every 3–5 minutes until drying of secretions)
- When: For patients with excessive secretions, bradycardia, or hemodynamic compromise due to muscarinic overstimulation
- Monitoring: Serial cardiac monitoring and reassessment of secretions, heart rate, and blood pressure
- Avoid high doses that risk atropine toxicity (e.g., tachycardia, urinary retention, hyperthermia)
- In suspected organophosphate poisoning, check for nicotinic effects (i.e., muscle weakness) – atropine does not reverse these symptoms
- Be cautious if the ECG shows conduction abnormalities before implementing additional therapies
- Goal: Reverse life‐threatening muscarinic symptoms (e.g., bronchorrhea and bradycardia) and stabilize the patient
- Hold/stop if: Secretions diminish and adverse effects (e.g., severe tachycardia) emerge
Dosing
| Population | Atropine Dose | Max (per bolus) | Notes |
|---|
| Adult | 0.02 mg/kg IV bolus; titrate by doubling dose every 3–5 minutes | Varies; often up to 2–4 mg in total | Titrate to effect – drying of secretions and improved hemodynamics 52 |
| Peds | Use weight-based dosing (0.02 mg/kg IV) | Monitor cumulative dose over repeated boluses | Similar titration to adult guidelines |
For organophosphate poisoning (a common cause of cholinergic toxicity), adjunct therapy with pralidoxime is indicated:
| Population | Pralidoxime Dose | Max/Notes |
|---|
| Adult | 30 mg/kg IV bolus, then infusion at 8 mg/kg/hr if needed | Addresses nicotinic effects (e.g., muscle weakness) and reactivates cholinesterase 5 |
Adjustments
- Renal/Hepatic: No specific adjustments for atropine; dosing for pralidoxime is standard unless significant organ dysfunction exists
- Obesity: Dose based on actual body weight may be considered, with careful titration
Adverse effects to watch for
- Atropine: Tachycardia, blurred vision, urinary retention, hyperthermia
- Pralidoxime: Dizziness, headache, infusion-related reactions
Alternatives
- Benzodiazepines (e.g., midazolam 0.2 mg/kg IV) for seizure control or agitation — they do not reverse the cholinergic effects but help with supportive sedation 5
- Supportive care measures (airway management, oxygen supplementation)
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