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An overdose of extended-release guanfacine
Daniel M Fein1, Zoabe F Hafeez, Christopher Cavagnaro
1Division of Pediatric Emergency Medicine, Albert Einstein College of Medicine, Children's Hospital at Montefiore, Bronx, NY 10467, USA. danfein@gmail.com
Pediatric Emergency Care
|August 9, 2013
Summary
Extended-release guanfacine overdose in a child caused prolonged hypertension and hypotension. Emergency physicians must recognize this rare but serious toxicity presentation for effective patient management.
Area of Science:
- Pharmacology
- Toxicology
- Pediatrics
Background:
- Extended-release guanfacine, a centrally acting α2-adrenergic agonist, is approved for attention-deficit/hyperactivity disorder (ADHD).
- ADHD and Tourette syndrome are increasingly prevalent conditions managed with medications like extended-release guanfacine.
Observation:
- A 12-year-old boy with ADHD and Tourette syndrome presented with lethargy, bradycardia, and hypertension 18 hours after ingesting an excessive dose of extended-release guanfacine.
- Hypertension persisted for 24 hours, requiring intravenous nicardipine, followed by 2.5 days of symptomatic hypotension.
Findings:
- This case illustrates an unusually prolonged and biphasic course (hypertension then hypotension) following guanfacine overdose.
- The protracted toxicity highlights the complex and variable presentation of centrally acting α2-adrenergic agonist ingestions.
Implications:
- Emergency physicians require heightened awareness of extended-release guanfacine toxicity, especially the potential for prolonged and severe hemodynamic instability.
- Familiarity with managing such rare presentations is crucial given the drug's increasing prescription rates for pediatric neurodevelopmental disorders.
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