Clonidine toxicity: Difference between revisions

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[[File:Clonidine.png|thumb|2D molecular structure of Clonidine]]
[[File:Clonidine.png|thumb|2D molecular structure of Clonidine]]
==Background==
==Background==
*Alpha-2 and opioid receptor agonist
*Class: Imidazolines
**[[Clonidine]]
**Guanfacine
**[[Oxymetazoline]](Afrin)
**Tetrahydrolozine (Visine)
**Naphazoline (Naphcon)
**Apraclonidine
-2, imidazoline, and opioid receptor agonist
**α2-agonism leads to activation of inhibitory neurons in the nucleus tractus solitarius causing decreased norepinephrine release, precipitating decreased sympathetic outflow
**Agonism of imidazoline receptors in the brain can cause unconsciousness, hypotension, and bradycardia
*Clonidine is used therapeutically for hypertension, opioid abuse, PTSD, and tobacco withdrawal; criminally, it has been used for drug-facilitated sexual assault


==Clinical Features==
==Clinical Features==
*Cardiac
*Note that initial presentation may stem from non-specific peripheral alpha1 agonism, and produce hypertension and reflex tachycardia
*Cardiac (alpha2)
**Bradycardia
**Bradycardia
**Hypotension
**Hypotension
*Neuro
*Neuro
**CNS depression (most common)
**Lethargy (may progress to apnea)
**Lethargy (may progress to apnea)
**Miotic pupils
**Miotic pupils
**Respiratory depression
*Respiratory
**Hypoventilation
**Hypoxia
**Cheynes-Stokes respiration
**Periodic apnea
*Hypothermia
*Can mimic opioid overdose
**obtundation, miosis, respiratory depression, and hypothermia
*Can mimic digoxin, Beta-blocker, or CCB toxicity with hypotension and bradycardia
*Withdrawal from clonidine presents with tachycardia, hypertension, tremors, and agitation


==Differential Diagnosis==
==Differential Diagnosis==
{{Template:Toxidrome Chart}}
{{Template:Toxidrome Chart}}


==Diagnosis==
==Evaluation==
*Diagnosis is largely based on history and clinical picture; there is no readily available serum test
*Serial ECGs
*Continuous cardiac monitoring
*Clonidine itself does not cause electrolyte derangements


==Treatment==
==Management==
*Respiratory/neuro depression
*Respiratory/neuro depression
**Naloxone
**[[Naloxone]]
***High dose may be required (up to 10mg)
***High dose may be required (up to 10mg)
***Not always effective
***Not always effective
*Bradycardia
***May require infusion, typically 2/3 effective treatment dose per hour
**Atropine
*[[Bradycardia]]
*Hypotension
**[[Atropine]]
**IVF
*[[Hypotension]]
**[[IVF]]
**Vasopressors if not responsive to fluids
 
==Disposition==


==References==
==References==
<references/>
<references/>
*Tintinalli
 


==See Also==
==See Also==

Revision as of 20:37, 20 November 2019

2D molecular structure of Clonidine

Background

  • Class: Imidazolines
  • α-2, imidazoline, and opioid receptor agonist
    • α2-agonism leads to activation of inhibitory neurons in the nucleus tractus solitarius causing decreased norepinephrine release, precipitating decreased sympathetic outflow
    • Agonism of imidazoline receptors in the brain can cause unconsciousness, hypotension, and bradycardia
  • Clonidine is used therapeutically for hypertension, opioid abuse, PTSD, and tobacco withdrawal; criminally, it has been used for drug-facilitated sexual assault

Clinical Features

  • Note that initial presentation may stem from non-specific peripheral alpha1 agonism, and produce hypertension and reflex tachycardia
  • Cardiac (alpha2)
    • Bradycardia
    • Hypotension
  • Neuro
    • CNS depression (most common)
    • Lethargy (may progress to apnea)
    • Miotic pupils
    • Respiratory depression
  • Respiratory
    • Hypoventilation
    • Hypoxia
    • Cheynes-Stokes respiration
    • Periodic apnea
  • Hypothermia
  • Can mimic opioid overdose
    • obtundation, miosis, respiratory depression, and hypothermia
  • Can mimic digoxin, Beta-blocker, or CCB toxicity with hypotension and bradycardia
  • Withdrawal from clonidine presents with tachycardia, hypertension, tremors, and agitation

Differential Diagnosis

Toxidrome Chart

Finding Cholinergic Anticholinergic Sympathomimetic Sympatholytic^ Sedative/Hypnotic
Example Organophosphates TCAs Cocaine Clonidine ETOH
Temp Nl Nl / ↑ Nl / ↑ Nl / ↓ Nl / ↓
RR Variable Nl / ↓ Variable Nl / ↓ Nl / ↓
HR Variable ↑ (sig) Nl / ↓ Nl / ↓
BP Nl / ↓ Nl / ↓
LOC Nl / Lethargic Nl, agitated, psychotic, comatose Nl, agitated, psychotic Nl, Lethargic, or Comatose Nl, Lethargic, or Comatose
Pupils Variable Mydriatic Mydriatic Nl / Miotic
Motor Fasciculations, Flacid Paralysis  Nl Nl / Agitated Nl
Skin Sweating (sig) Hot, dry Sweating Dry
Lungs Bronchospasm / rhinorrhea Nl Nl Nl
Bowel Sounds Hyperactive (SLUDGE) ↓ / Absent Nl / ↓ Nl / ↓
^Consider Sympatholytic when looking at Sedative OD or someone who doesn't respond to Narcan
Withdrawal from substances have the opposite effect

Evaluation

  • Diagnosis is largely based on history and clinical picture; there is no readily available serum test
  • Serial ECGs
  • Continuous cardiac monitoring
  • Clonidine itself does not cause electrolyte derangements

Management

  • Respiratory/neuro depression
    • Naloxone
      • High dose may be required (up to 10mg)
      • Not always effective
      • May require infusion, typically 2/3 effective treatment dose per hour
  • Bradycardia
  • Hypotension
    • IVF
    • Vasopressors if not responsive to fluids

Disposition

References


See Also

Toxicology (Main)