Gamma-Butyrolactone (GBL) has widespread industrial use. It is a common solvent found in
paint strippers, nail polish removers, stain removers and circuit board cleaners. It is also a
common intermediate in industrial chemistry including the manufacture of pyrrolidones and in
some pharmaceuticals. International production and trade of GBL is at least of the order of
hundreds of thousands of metric tons. Single consignments can be up to 500 tons alone.
Since the end of the 1990s, certain individuals have ingested GBL for the purpose of
intoxication. GBL is chemically similar to gamma-hydroxybutyrate (GHB), a compound in
Schedule II of the 1971 Convention. GHB is easily synthesized from GBL by changing the pH
with addition of an alkali (e.g. sodium hydroxide), and recipes and “kits” have been provided
on the Internet identifying or providing the ingredients to do so. Synthetic conversion of GBL
to make GHB is unnecessary, however, because it is rapidly metabolized to GHB following its
ingestion, and its clinical effects are identical to GHB. This makes the epidemiology of GBL’s
and GHB’s use and abuse intrinsically (and forensically) linked. Because the onset of action of
GBL is faster than GHB, its potency greater, and its duration of activity longer, its abuse
potential may actually be greater than GHB itself.
There is a steep dose-effect curve between doses producing desired and excessive effects, and
there have been numerous published reports of adverse reactions to GBL including fatalities.
Signs and symptoms can include: euphoria, relaxation, reduced inhibition and sedation
progressing to vomiting, urinary and fecal incontinence, agitation, convulsions, bradycardia,
respiratory depression, coma and death.
GBL is sold as a liquid, often presented in illicit sale as GHB. Prices of GBL vary between 9
cents to 2 euros for a recreational dose (1 ml). GBL is often used with other drugs, particularly
cannabis, alcohol and ecstasy. Accurate estimates of the prevalence of the use of GBL for its
intoxicating effects are not available, in part because of its rapid conversion to GHB, but also
because it is not routinely tested during forensic examination. Best estimate of the prevalence
of its use, while giving consideration that reports of GHB use may actually be attributable to
the ingestion of GBL, is low in Europe and the United States, but possibly significantly higher
in other pockets of the world such as Australasia.
In view of concerns about the illicit trade and use of GBL, some Member States have chosen to
control it under drug control or equivalent legislation. Several member states treat the illicit use
and sale of GBL as involving a direct analog of GHB and can prosecute as such. Furthermore,
the European Community and the Member States have taken additional voluntary measures to
prevent its diversion.
GBL has the capacity to produce a state of dependence, and can produce similar effects as the
Schedule II compound, GHB. However, the prevalence and magnitude of the public health and
social problems its use specifically creates is difficult to accurately estimate. Coupled with the
appreciation that GBL is used as an industrial chemical with production and trade in the
hundreds of thousands of metric tons, controlling it as a psychotropic substance equivalent to
GHB would not likely result in benefits sufficient to justify the burdens such controls would
36th ECDD (2014) Agenda item 4.3 Gamma‐butyrolactone (GBL)
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