Systemic toxicity from subcutaneous brimonidine injection successfully treated with naloxone

Area of Science:

• Ophthalmology
• Toxicology
• Emergency Medicine

Background:

• Brimonidine tartrate is a topical alpha-2 adrenergic agonist used to treat glaucoma.
• Ingestion in infants can cause drowsiness, hypotension, bradycardia, and respiratory depression.
• The effects of intentional subcutaneous injection in adults are not well-documented.

Observation:

• A 73-year-old female intentionally injected brimonidine ophthalmic solution subcutaneously.
• She presented with lethargy, severe hypotension (BP 91/24 mmHg), and bradycardia (paced at 60 bpm).
• Central nervous system depression was noted, prompting intervention.

Findings:

• Subcutaneous brimonidine injection led to systemic alpha-2 adrenergic agonist toxicity.
• The patient's symptoms mimicked opioid toxicity, characterized by sympatholytic effects.
• Intravenous fluids and escalating doses of naloxone, including a continuous infusion, were required for stabilization.

Implications:

• This case highlights a novel route of brimonidine abuse and potential toxicity.
• High-dose naloxone demonstrated efficacy in reversing CNS depression and hemodynamic instability in this alpha-2 agonist overdose.
• Clinicians should consider alpha-2 adrenergic agonist toxicity in patients presenting with sympatholytic symptoms, even without a history of opioid use.