One of our readers of the Question of the Week asked for a summary of GHB. Here it is.
GHB is an endogenous short chain fatty acid occurring in the brain and peripheral tissues. GHB is formed from the degradation of gamma-aminobutyric acid (GABA), the inhibitory neurotransmitter (NT) in the brain. GHB is a NT and activates GHB receptors at normal brain concentration. However when exogenous GHB is administered, it also activates GABA receptors. Many organ systems are impacted as a result of the receptor activation (and interaction with other receptors). NT (such as dopamine and met-enkephalin) are released, minute ventilation and heart rate are decreased, blood pressure is increased, memory and learning are impacted, disinhibition occurs, and with higher dose, somnolence and coma occur. There is very little known about endogenous GHB.
GHB has been used recreationally [“Grevious Bodily Harm”, “Easy Lay”, “Liquid Ecstasy”, “Salty Water” (GHB has slightly salty taste)]. “Illicit GHB” is now a Schedule I and “Medical GHB” is Schedule III. Xyrem® is GHB that has been approved for the treatment of narcolepsy. Gamma butyrolactone (GBL), an industrial solvent, is converted to GHB by a serum lactonase. GBL is usually mixed with a base (such as baking soda) to make GHB (recipe easily found on the internet). 1,4 Butanediol, a naturally occurring aliphatic alcohol used in the synthesis of polyurethanes and polyvinylpyrrolidone, is converted to GHB via alcohol dehydrogenase (ADH) and can be consumed as purchased.
GHB effects last 2-5 hours and a hangover does not occur. The people who use it state it increases sexual desire, decreases inhibition and causes a relaxed mood-like ethanol or Ecstasy. Reasons given for use are recreation (18%), enhancement of sex (18%), sociability (13%) and to explore altered states of consciousness (13%). (Drug and Alcohol Dependence 2008)
Overdose (>50 mg/kg) leads to rapid progression to coma. Hypothermia, bradycardia, and decreased respiratory rate occur in 30%. There is a lack of distinctive markers for this overdose, other than the rapid progression to coma and rapid awakening, usually about two hours later. GC (gas chromatography or GC-MS (mass spectrometry) must be employed to identify GHB in the urine. Flumazenil, physostigmine, and naloxone have all been reported to awaken patients in GHB-induced coma but most of these reports lack scientific credibility for a number of reasons. Both ethanol and 1,4 Butanediol compete for alcohol dehydrogenase, so if they are consumed together, the symptoms (and coma) may last much longer than usual.
GHB is known as a Drug to Facilitate Sexual Assault as it can act rapidly, and cause disinhibition, relaxation of voluntary muscle and amnesia.
Research areas include the use of GHB for the treatment of Fibromyalgia and Cerebral Ischemia.
Question prepared by: Donna Seger, MD Medical Toxicologist
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Donna Seger, MD
Tennessee Poison Center
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