Gamma hydroxybutyrate toxicity: Difference between revisions
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==Clinical Features==
==Clinical Features==
*cns and respiratory depression  
"Classic Presentation: Young adult presents comatose and is intubated for airway protection and subsequently awakens while in the emergency department. When awake, can be safely discharged"
*also cardioa and gi symptoms  
*CNS and respiratory depression  
*many times have cointoxicants
*also cardiac and GI symptoms  
*often found to have co-intoxicants
*usually young white male from nightclub  
*usually young white male from nightclub  
*can have nausea and vomiting, respiratory deprsn, bradycardia, seizure  
*may present with nausea and vomiting, respiratory depression, bradycardia, seizure  
*get euphoria s hang over
*may also have ataxia, nystagmus, somnolence and aggression  
*can also get ataxia, nystagmus, somnolence and aggression  
*respiratory/CNS depression resolves abruptly  
*resp/ cns deprrsion resolves abruptly  
*respiratory depression worse with other CNS depressants ([[alcohol]], [[benzodiazepines]], etc)
*resp depression worse with other cns depressants-alcohol  
*periods of apnea and hyperventilation
*periods of apnea and hyperventilation-is periodic breathing
*decreases respiratory rate but tidal volume increases so minute volume stable  
*decreases respiratory rate but tidal vol increases so minute vol stable  
*can also have seizure but EEG shows no epileptiform changes  
*can also have seizure but eeg shows no epileptiform changes  
*bradycardia, hypotension
*bradycardia, hypotension*ekg change occasionally but rare  
*ekg change occasionally but rare  
*also get vomitting, hypothermia  
*also get vomiting, hypothermia  
===Clinical Course===
===Clinical Course===
*recover 2-6 hrs  
*recover 2-6 hrs  

Revision as of 05:17, 28 January 2021

Background

  • Abbreviation: GHB
  • Frequently referred to as the "date rape drug"
  • Central nervous system depressant
  • GABA-B agonist (as opposed to GABA-A agonists - alcohol, benzodiazepines, etc)
  • Abused for:
    • Body building or sleep enhancement
    • euphoric, sexual, stimulant, and relaxant effects
    • Surreptitious drugging to facilitate sexual assault
  • Also used therapeutically in the treatment of narcolepsy[1]

Pharmacokinetics

  • Effects start in 15-20 minutes, peak in 30-60 minutes,
  • Lipid soluble, readily crosses the blood brain barrier
  • Elimination is dose-dependent; half-life of 20-50 minutes
  • The duration of GHB's clinical effects depends upon the dose, and ranges from 2.5-4 hours

Pharmacology

  • Is a metabolite and precursor of GABA
  • Interacts with GHB-specific receptors and also acts as a direct agonist of GABA-B receptors
  • Affects multiple neurotransmitter systems, including those of opioids, dopamine, serotonin, glutamate, and acetylcholine
  • Gamma butyrolactone (GBL) and 1,4 butanediol (BD) are GHB analogs that are rapidly metabolized to GHB after ingestion, with the same toxic and recreational effects

Clinical Features

"Classic Presentation: Young adult presents comatose and is intubated for airway protection and subsequently awakens while in the emergency department. When awake, can be safely discharged"

  • CNS and respiratory depression
  • also cardiac and GI symptoms
  • often found to have co-intoxicants
  • usually young white male from nightclub
  • may present with nausea and vomiting, respiratory depression, bradycardia, seizure
  • may also have ataxia, nystagmus, somnolence and aggression
  • respiratory/CNS depression resolves abruptly
  • respiratory depression worse with other CNS depressants (alcohol, benzodiazepines, etc)
  • periods of apnea and hyperventilation
  • decreases respiratory rate but tidal volume increases so minute volume stable
  • can also have seizure but EEG shows no epileptiform changes
  • bradycardia, hypotension
  • ekg change occasionally but rare
  • also get vomiting, hypothermia

Clinical Course

  • recover 2-6 hrs
  • may be extubated and sent home
  • if longer than 6hr, look for other cause
  • can have cross tolerance with other drugs-alcohol and others that effect liver p450 cytochome oxidase system

Differential Diagnosis

Sedative/hypnotic toxicity

Drugs of abuse

Evaluation

  • Not detectable on routine toxicology screens

Management

  • supportive
  • look for coingestants and occult trauma
  • charcoal not helpful since rapidly absorbed and since can vomit and aspirate
  • protein bound so can use dialysis*but so short course usually do not need.

Antidotes

Disposition

See Also

References

  1. ↑ Mamelak M, Scharf MB, Woods M. Treatment of narcolepsy with gamma-hydroxybutyrate. A review of clinical and sleep laboratory findings. Sleep. 1986;9(1 Pt 2):285-289. doi:10.1093/sleep/9.1.285
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