Clonidine Overdose
The most likely ingested medication is clonidine, based on the classic presentation of profound CNS depression, respiratory depression (RR 6/min), bradycardia (HR 58 bpm), hypotension (BP 80/40), and miosis (2 mm pupils bilaterally). 1
Clinical Presentation Supporting Clonidine Toxicity
This patient demonstrates the pathognomonic toxidrome of clonidine overdose:
- CNS depression with lethargy and decreased responsiveness is the hallmark of clonidine toxicity, occurring in virtually all cases 1, 2
- Miosis (pinpoint pupils at 2 mm) is a characteristic finding that distinguishes clonidine from other cardiovascular medications 1, 3
- Respiratory depression (RR 6/min) is more common than previously recognized and can progress to apnea 4, 2
- Bradycardia and hypotension occur together in the majority of clonidine overdoses 1, 3, 5
- Symptoms typically develop within 30 minutes to 2 hours after ingestion, consistent with acute presentation 1
Why Other Medications Are Less Likely
Beta-blockers (Metoprolol) would cause bradycardia and hypotension but characteristically produce hypoglycemia rather than miosis, and do not typically cause this degree of CNS depression or respiratory depression 6
Calcium channel blockers (Diltiazem) cause bradycardia and hypotension but produce hyperglycemia (not miosis) due to inhibition of pancreatic insulin release, and lack the profound CNS depression seen here 6
Amiodarone can cause bradycardia and hypotension but does not produce miosis or this degree of CNS/respiratory depression 7
ACE inhibitors (Lisinopril) cause hypotension but not bradycardia, miosis, or CNS depression 7
Immediate Management Priorities
Airway management takes precedence given the respiratory rate of 6/min and lethargy—prepare for bag-mask ventilation and potential intubation 7, 1
Atropine 0.5-1.0 mg IV should be administered for symptomatic bradycardia, which has proven effective in reversing clonidine-induced bradycardia 7, 4, 3
Intravenous fluid resuscitation is the first-line treatment for hypotension 1, 4, 3
Dopamine infusion should be initiated if hypotension persists despite adequate fluid resuscitation 4, 3, 5
Naloxone may be considered as it can reverse CNS depression, respiratory depression, and hypotension in clonidine overdose, though blood pressure monitoring is essential as paradoxical hypertension can occur 1, 4
Critical Pitfalls to Avoid
Do not induce vomiting with ipecac due to rapid onset of CNS depression 1
Avoid tolazoline as it has yielded inconsistent results and is not recommended as first-line therapy 1, 4, 3
Monitor for at least 24-48 hours as bradycardia can persist for 36 hours and altered mental status for 48 hours 2
As little as 0.1 mg of clonidine has produced toxicity in children, emphasizing the potency of this medication 1