PEDIATRIC PULSE

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Clonidine

Brandon Ho

Pathophysiology

Clonidine is an alpha-2 agonist that is used to treat hypertension, ADHD, and spasticity in pediatric patients. Other common medications in the same class include guanfacine, dexmetomidine, and oxymetazoline. Clonidine comes in PO and transdermal patch formulations. Clonidine has rapid GI absorption reaching peak concentrations in 3-5 hours. Patches can have delayed and prolonged presentations.

  •  Clonidine stimulates alpha-2 receptors in the CNS causing:

    • Decrease sympathetic outflow

    • Increase GABA release

    • Endogenous opioid release

  • Clonidine stimulates alpha-2 receptors in the peripheral vasculature causing vasoconstriction and initial hypertension then a hypotensive phase

Presentation

Toxidrome: AMS, miosis, respiratory depression, bradycardia, and hypotension

  • Neurologic: AMS, lethargy, coma, hypotonia, hyporeflexia, seizures

  • Ophthalmic: Miosis

  • Respiratory: Respiratory depression, periodic apnea, Cheyne-stokes respiration

  • Cardiovascular: Early transient hypertension secondary to peripheral vasoconstriction followed by hypotension and bradycardia. Rare cases of AV block and sinus arrest. 

  • Metabolic: Hypothermia, pallor

Diagnosis

Consult Poison Control: 1800-222-1222

What type of product was ingested (immediate vs. sustained release)?

Any presence of synergistic co-ingestants (other antihypertensives, sedatives)? 

  1. Workup: Blood gas, POC glucose, CMP, acetaminophen level, salicylate level, ethanol level, UDS, EKG

  2. Consider head CT if focal neurologic findings or persistent alterations in mental status

Management

Disposition:

  • All symptomatic patients regardless of response to naloxone require admission for monitoring.

  • Asymptomatic patients who ingest a transdermal patch should be admitted and closely monitored as symptoms may not present until 24 hours.

  • Asymptomatic patients 6 hours post-ingestion of immediate release oral formulations may be discharged home with close follow-up

References

  1.  Manzon L, Nappe TM, DelMaestro C, et al. Clonidine Toxicity. [Updated 2020 Jun 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459374/

  2. Wedin GP, Richardson SL, Wallace GH. Clonidine Poisoning in Children. Am J Dis Child. 1990;144(8):853–854. doi:10.1001/archpedi.1990.02150320015011