ACMT Toxicology Visual Pearl: Sleeping with the Fishes

2. Gamma-hydroxybutyrate (GHB)

Also known as “Easy Lay,” “Georgia Home Boy,” “Juice,” “Liquid Ecstasy,” “Mils,” “G,” “Liquid X,” “Liquid G,” and “Fantasy” have been dispensed in these fish-shaped soy sauce containers [1, 2].

Background [1, 3-7]

GHB was popular in the 1980s as a dietary supplement, particularly by bodybuilders, as it was reported to increase growth hormone release. Subsequently, due to its intoxicating effects, GHB found its way into the nightlife scene internationally in the 1990s, predominantly in nightclubs catering to the gay, bisexual, and other men who have sex with men (GBMSM) community. Due to its sedative effects, GHB has also been used to facilitate sexual assault. The commercially available organic solvents gamma-butyrolactone (GBL) and 1,4-butanediol (BD) are rapidly converted in vivo into GHB and its analogues [3,4]. Use of GHB and analogues is now most associated with electronic dance music parties and is often used in “chemsex” (this is the use of substances, particularly stimulants and GHB, surrounding sexual activity) [3-7].  Due to the risk of toxicity and malicious use, GHB and its analogues have been controlled in many countries under relevant legislation. Gamma Hydroxybutyrate (GHB), however, can be legally prescribed in the form of sodium oxybate (Xyrem®) to treat narcolepsy [1].

How does GHB cause toxicity? [1-8]

• At low doses, GHB functions as a central nervous system depressant by interacting and binding with the GABA-B receptor, thus mediating its sedative, amnestic, and anxiolytic properties.
• Users typically take 0.5 – 2 mL to achieve the desired effect, which has onset within minutes and lasts 1 – 2 hours, so typically individuals will re-dose multiple times during a single “use session”.
• GHB has a steep concentration-effect curve, and inadvertent overdoses are common; users typically use 1-2 mL per dose, and a small amount more may result in coma and respiratory arrest.
• Fatal GHB overdoses commonly occur in combination with sedatives such as ethanol or benzodiazepines.

How does GHB toxicity present? [1-8]

• CNS: loss of consciousness, coma, and seizure-like activity
• Cardiovascular: sinus bradycardia, hypotension
• Respiratory: mild bradypnea to respiratory arrest
• Other: hypothermia, nausea, vomiting, miosis
• Patients typically awaken within several hours of presentation, although some may experience a period of fluctuating consciousness during recovery.

How do you treat GHB toxicity? [1-8]

• Diagnosis is primarily clinical, therefore obtaining collateral history can be instrumental in making the diagnosis.
• Treatment is supportive.
• Airway management may be necessary.
• Be aware that patients often suddenly awaken and, if intubated, can rapidly self-extubate, potentially leading to vocal cord damage.
• Patients can be safely discharged after a period of observation once they have returned to baseline.
• As appropriate, screen for GHB dependency and refer for drug treatment services.

Bedside Pearls

• History is essential to making the diagnosis of GHB intoxication.
• Treatment is supportive with airway management if indicated.
• Rapid resolution may occur, but there is a risk of vocal cord damage if they self-extubate.
• Patients with GHB toxicity should be screened for dependency, counselled, and referred appropriately.