Post-injection delirium/sedation syndrome from long-acting olanzapine intramuscular injection is rapidly reversed with physostigmine and rivastigmine

Our patients support the hypothesis that post-injection delirium/sedation syndrome includes an antimuscarinic mechanism responsive to acetylcholinesterase inhibitors. Early administration of physostigmine, followed by rivastigmine, may be an effective, targeted approach. We propose their use should be first-line when treating antimuscarinic delirium in post-injection delirium/sedation syndrome.