UMEM Educational Pearls

Title: Utility of physostigmine in antimuscarinic delirium

Category: Toxicology

Keywords: antimuscarinic/anticholinergic toxicity, reversal of delirium (PubMed Search)

Posted: 7/12/2018 by Hong Kim, MD
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From 1960s to 1970s, physostigmine was routinely administered as part of the "coma cocktail." Since the publication of two cases by Pentel (1980) that resulted in asystole after administration of physostigmine in TCA poisoned patient, its use has declined significantly.

However, physostigmine still possess limited but clinically useful role in the management of patients with antimuscarinic/anticholinergic induced delirium.

Recently, a prospective observational study was performed in the use of physostigmine when recommended by a regional poison center.

In 1 year study period, physostigmine was recommended by a regional poison center in 125 of 154 patients with suspected antimuscarinic/anticholinergic toxicity. 

common exposures were

  1. antihistamines (68%)
  2. analgesics (19%)
  3. antipsychotics (19%)

57 of 125 patients received physostigmine per treating team.

  • median dose of physostigmine administered: 2 mg

Of the remaining patients,

  • 35 patients did not receive any sedative agents
  • 55 received benzodiazepines (56%)
  • others received propofol (n=10), haloperidol (n=8), olanzapine (n=4), dexmedetomidine (n=3), etc.

Delirium control

  • Physostigmine group 79% (45 of 57)
  • No-physostigmine group: 36% (35 of 97)

Adverse events (physostigmine group vs. non-physo group) - no statistically significant difference.

  • Intubation (n=7): 2 (3.5%) vs. 5 (5.2%)
  • physical restraints (n=10): 3 (5.3%) vs. 7 (7.2%)
  • vomiting (n=4): 3 (5.3%) vs. 1 (1.0%)

Conclusion:

Physostigmine can safely control antimuscarinic/anticholinergic-induced delirium.

 

 

References

Boley SP et al. Physostimgine is superior to non-antidote therapy in the management of antimuscarinic delirium: a prospective study from a regional poison center. Clin Toxicol 2018 Jun 29:1-6. doi: 10.1080/15563650.2018.1485154. [Epub ahead of print]