Antidote: atropine

Treat muscarinic effects of cholinergic toxidrome, especially bradycardia and increased pulmonary secretions, early with atropine. Atropine requirements vary enormously between patients and different cholinergic drugs and toxins.

For some patients with a cholinergic toxidrome due to organophosphate and carbamate poisonings, very high cumulative loading doses up to 100 mg of atropine may be required—see the individual monograph for an appropriate regimen.

For all other patients with cholinergic toxidrome, use:

atropine 0.6 mg (child: 0.02 mg/kg up to 0.6 mg) intravenously, every 3 to 5 minutes guided by clinical response up to a maximum total dose of 3 mg (child: 1.8 mg). cholinergic toxidrome atropine

Titrate the atropine dose to achieve the target end points for atropinisation:

clear chest with no wheeze on auscultation
heart rate more than 80 beats per minute
systolic blood pressure more than 80 mmHg.

While titrating the dose, observe patients closely for signs of over-atropinisation and adjust the atropine dose accordingly. The most important signs of over-atropinisation are confusion, pyrexia and absent bowel sounds.