# Antimuscarinic Toxicity Safely Managed with High-Dose Transdermal Rivastigmine: A Case Report

## TL;DR

A patient with antimuscarinic toxicity was safely treated with high-dose transdermal rivastigmine after physostigmine shortages.

## Contribution

High-dose transdermal rivastigmine may safely manage antimuscarinic toxicity when physostigmine is unavailable.

## Key findings

- The patient tolerated 26.6 mg/24 hours transdermal rivastigmine without adverse effects.
- Higher doses of rivastigmine correlate with faster peak concentration and improved symptom control.
- Central distribution of rivastigmine occurs more rapidly than serum distribution.

## Abstract

Antimuscarinic toxicity, which can cause delirium and unsafe behavior, may result from an adverse effect of prescribed medications or from non-medical substance use. Physostigmine shortages have prompted use of transdermal rivastigmine for management of antimuscarinic toxicity; however, symptom control is equivocal at standard dosing.

A patient with antimuscarinic toxicity was treated with physostigmine and transitioned to 26.6 milligrams/24 hours transdermal rivastigmine for sustained symptom control. He experienced no adverse effects and tolerated floor admission.

There is mechanistic plausibility supporting safe, sustained control of antimuscarinic toxicity with high-dose transdermal rivastigmine. Central distribution is more rapid than serum distribution and higher doses correlate with a shorter time to peak concentration.