Basics
Description
- Naturally occurring analog of γ-aminobutyric acid (GABA)
- Used medically for narcolepsy
- Nonmedical uses:
- Bodybuilding agent
- Euphoric agent
- Date-rape/predatory agent
- γ-Hydroxybutyrate (GHB) precursors (γ-butyrolactone [GBL], 1,4 butanediol [1,4-BD], GHV [γ-hydroxyvalerate], and GVL) have same effects as GHB.
- Onset of activity: 15-30 min after ingestion
- Duration of effect: 2-6 hr
Etiology
Deliberate or accidental ingestion of GHB �
Diagnosis
Signs and Symptoms
- CNS:
- CNS depression
- Ataxia/dizziness
- Impaired judgment
- Aggressive behavior
- Clonic movements of the extremities
- Coma
- Seizures
- Pulmonary:
- Respiratory depression
- Apnea
- Laryngospasm (rare)
- GI:
- Cardiovascular:
- Bradycardia
- Atrioventricular block
- Hypotension
- Other:
- Withdrawal symptoms:
- HTN
- Tachycardia
- Hyperthermia
- Agitation
- Diaphoresis
- Tremors
- Nausea, vomiting, and abdominal cramping
- Hallucinations, delusions, and psychosis
Essential Workup
- Diagnosis based on clinical presentation and an accurate history
- Exclude coingestants if signs and symptoms inconsistent with GHB intoxication
Diagnosis Tests & Interpretation
Lab
- Confirmatory GHB screen is typically a send-out lab and does not change ED management.
- Urine toxicology screen to exclude coingestants
- Serum alcohol level
- Urinalysis and creatine kinase (CK) if suspected rhabdomyolysis from prolonged immobilization or agitation
Imaging
- ECG:
- Sinus bradycardia
- Atrioventricular block
- CXR:
- Head CT if suspected occult head trauma
Differential Diagnosis
- Alcohol intoxication
- Barbiturate overdose
- Benzodiazepine overdose
- Neuroleptic overdose
- Opiate overdose
- Withdrawal:
- Alcohol withdrawal
- Sedative-hypnotic withdrawal
Treatment
Pre-Hospital
Transport all pills/bottles and drug paraphernalia involved in overdose for identification in ED. �
Initial Stabilization/Therapy
- ABCs:
- Airway control essential
- Administer supplemental oxygen
- Intubate if indicated
- Administer thiamine, dextrose (or Accu-Chek), and naloxone for depressed mental status.
Ed Treatment/Procedures
- Supportive care
- Bradycardia:
- Hypotension:
- 0.9% NS IV fluid bolus
- Trendelenburg
- Dopamine titrated to pressure
- Seizures:
- Treat initially with benzodiazepine.
- Treat refractory seizures with phenobarbital.
- Withdrawal:
- Treat aggressively with benzodiazepine.
- Treat with phenobarbital or propofol if large doses of benzodiazepines unsuccessful.
Medication
- Dextrose: 50-100 mL D50 (peds: 2 mL/kg of D25 over 1 min) IV; repeat if necessary
- Diazepam: 5-10 mg (peds: 0.2-0.5 mg/kg) IV q10-15min
- Dopamine: 2-20 μg/kg/min with titration to effect
- Lorazepam: 2-4 mg (peds: 0.03-0.05 mg/kg) IV q10-15min
- Naloxone: 0.4-2 mg (peds: 0.1 mg/kg; neonatal: 10-30 μg/kg) IV or IM
- Phenobarbital: 10-20 mg/kg IV (loading dose) monitor for respiratory depression with IV administration
- Propofol: 0.5-1 mg/kg IV (loading dose), then 5-50 μg/kg/min (maintenance dose)
- Thiamine (vitamin B1): 100 mg (peds: 50 mg) IV or IM
Follow-Up
Disposition
Admission Criteria
- Intubated patient
- Patient with hypothermia or other hemodynamic instability
- Coingestion prolonging duration of intoxication
Discharge Criteria
- Asymptomatic after 6 hr of observation
- No clinical evidence of withdrawal syndrome
Withdrawal from GHB is life-threatening and appears similar to alcohol withdrawal. Prolonged inpatient treatment may be indicated. �
Follow-Up Recommendations
- Substance abuse referral for patients with recreational drug abuse.
- Patients with unintentional (accidental) poisoning require poison prevention counseling.
- Patients with intentional (e.g., suicide) poisoning require psychiatric evaluation.
Pearls and Pitfalls
- Consider nontoxicologic causes for persistent altered mental status
- Routine hospital drug testing will not confirm GHB or other common recreational drugs of abuse
Additional Reading
- Gahlinger �PM. Club drugs: MDMA, gamma-hydroxybutyrate (GHB), Rohypnol, and ketamine. Am Fam Physician. 2004;69(11):2619-2926.
- Schep �LJ, Knudsen �K, Slaughter �RJ, et al. The clinical toxicology of γ-hydroxybutyrate, γ-butyrolactone and 1,4-butanediol. Clin Toxicol (Phila). 2012;50(6):458-470.
- van Noorden �MS, van Dongen �LC, Zitman �FG, et al. Gamma-hydroxybutyrate withdrawal syndrome: Dangerous but not well known. Gen Hosp Psychiatry. 2009;31(4):394-396.
- Wood �DM, Brailsford �AD, Dargan �PI. Acute toxicity and withdrawal syndromes related to γ-hydroxybutyrate (GHB) and its analogues γ-butyrolactone (GBL) and 1,4-butanediol (1,4-BD). Drug Test Anal. 2011;3(7-8):417-425.
- Zvosec �DL, Smith �SW, Porrata �T, et al. Case series of 226 γ-hydroxybutyrate-associated deaths: Lethal toxicity and trauma. Am J Emerg Med. 2011;29(3):319-332.
Codes
ICD9
968.4 Poisoning by other and unspecified general anesthetics �
ICD10
- T41.291A Poisoning by oth general anesthetics, accidental, init
- T41.293A Poisoning by other general anesthetics, assault, init encntr
- T41.294A Poisoning by oth general anesthetics, undetermined, init
- T41.292A Poisoning by oth general anesthetics, self-harm, init
SNOMED
- 269268004 Central nervous system depressants and anesthetic agent poisoning (disorder)
- 295591002 Central nervous system depressants and anesthetic overdose (disorder)