Have you heard of the ‘party drug’ GBL (gamma butyrolactone)? A survey of health workers’ knowledge of this potentially fatal drug

To the Editor

Gamma butyrolactone (GBL) is an illegal drug with potential for severe psychiatric consequences. GBL is a colourless, odourless liquid taken orally, with effects similar to alcohol. At doses of 0.3–1.2 mL, it causes euphoria, disinhibition, increased sex drive and increased energy. At doses >1.25 mL, it causes drowsiness, coma and death. GBL is used in the club scene and has been implicated in ‘date rape’ cases. It is a precursor of the active metabolite, gamma hydroxybutyric acid (GHB), which acts via GABAergic neuromodulatory pathways (Maitre, 1997).

GBL may cause extrapyramidal side effects and dependence, with potentially fatal withdrawal symptoms. Tolerance develops and users self-dose with up to 1–2 mL per hour. The withdrawal syndrome is similar to alcohol, although symptoms start sooner, a few hours after the last dose and may become serious within 24 hours. Withdrawal symptoms include hallucinations, delirium and seizures. Prevalence of GBL use is not clear as it is not included on the UK drug statistics database. Increasing numbers of people are seeking treatment for addiction (Schep et al., 2012). There was a single case of GBL withdrawal during my 6-month rotation at Huntercombe Hospital.

In view of the apparent lack of knowledge among my colleagues, I designed a cross-sectional questionnaire with multiple-choice and short-answer questions. Twenty healthcare workers including psychiatrists (2), a staff grade doctor (1), nurses (14) and healthcare support workers (3) responded.

The majority of respondents had never knowingly treated a patient who abused GBL; one had treated one patient and one two to five. Seven respondents correctly indicated that GBL is an illegal substance with potential for abuse. Two incorrectly believed it was a licensed medication, one that it was a ‘legal high’ and seven did not know. Five of 20 respondents correctly identified the acute effects of the drug, two (10%) knew the correct route of administration and two (10%) knew it could cause dependence. Five respondents knew it was a date rape drug, and seven could name some risks of the drug. None knew the chemical name for GBL, none knew whether withdrawal could be treated and none knew the relationship between GBL and GHB.

Knowledge about GBL was poor at our hospital, highlighting an educational need. Patients ought to be asked specifically about GBL when taking a drug and alcohol history. There are significant psychiatric and medical consequences of GBL abuse, and it is important for healthcare workers to identify and treat users appropriately.