II. Mechanism
- Adrenergic alpha-2 Agonist (similar to Clonidine, Dexmedetomidine) with central acting decrease in sympathetic tone
- Used as a Sedative, Analgesic and centrally acting Muscle relaxant in veterinary medicine
- Street name, "Horse Tranquilizer", added to injection Drugs of Abuse (e.g. Fentanyl, Cocaine) to enhance euphoria
- Associated with Opioid Overdose deaths, and unresponsive to Naloxone
III. Pharmacokinetics
- Typically injected, but is also well absorbed with ingested or insufflated
- Half-Life: 5 hours after injection
- Symptoms manifest with as little as 10 mg injected
IV. Findings
- Overdose unresponsive to Naloxone
- Neurologic
- Pupil Constriction (Miosis)
- Sedation
- Respiratory Depression
- Cardiovascular
- Bradycardia
- Hypotension (may follow initial Hypertension)
- Endocrine
- Hyperglycemia (mild)
- Skin
- Ulcerations at injection site
V. Labs
- See Unknown Ingestion
- Bedside Glucose
- No drug levels are available
VI. Diagnostics
VII. Management
- See Unknown Ingestion
-
Decontamination
- Consider Activated Charcoal if large ingestion within prior hour and protected airway
- Supportive Care
- Naloxone for Opioid coingestion reversal
- Endotracheal Intubation if indicated
- Supplemental Oxygen
- Symptomatic Bradycardia
- Hypotension
- Significant Ventricular Dysrhythmia
- Disposition
- Admit all symptomatic patients (e.g. Symptomatic Bradycardia, Hypotension)
- May discharge if asymptomatic at 4 to 6 hours from use
VIII. References
- Tomaszewski (2022) Crit Dec Emerg Med 36(6): 32