Administration

ALERT: Atropine should be available at the bedside and titrated to effect should excessive cholinergic toxicity develop.  A dose of atropine at half the physostigmine dose is recommended.

• Intermittent Infusion via large volume pump:  Dilute dose in 50 mL sodium chloride 0.9% and administer over 10 minutes. 
• Onset of action occurs between 5 and 10 minutes after IV administration and the duration varies between 30 min and 5 hours depending on the severity of the anticholinergic poisoning to be reversed. Additional doses of physostigmine may be required. 
• NOTE:  To minimize drug wastage, it is recommended that two doses be immediately prepared using the opened ampoule. 

Monitoring

• Cardiac monitoring
• Neurological examination  

Endpoint of therapy: Sustained resolution of agitation and delirium. 

Compatibility, Stability

• Compatible with sodium chloride 0.9%.
• Protect ampoules from light. 

Potential Hazards of Administration

• Muscarinic cholinergic effects such as bradycardia, atrioventricular block, asystole, nausea, vomiting, miosis, salivation, bronchorrhea, bronchospasm.
• Generalized convulsions, muscle weakness and fasciculation if there is significant stimulation of nicotinic cholinergic receptors.
• Rapid administration may cause bradycardia, hypersalivation leading to respiratory difficulty, and seizures. 
• Use caution in patients with underlying conditions including reactive airway disease, peripheral vascular disease and intestinal or bladder obstruction.