WHO Expert Committee on Drug Dependence – WHO Technical Report Series, No. 915 – Thirty-third Report
(2003; 31 pages) [French] [Spanish] View the PDF document
Table of Contents
View the document1. Introduction
View the document2. Scheduling criteria
Open this folder and view contents3. Critical review of psychoactive substances
Close this folder4. Pre-review of psychoactive substances
View the document4.1 Ketamine (INN)
View the document4.2 Zaleplon (INN)
View the document4.3 Zopiclone (INN)
View the document4.4 Butorphanol (INN)
View the document4.5 Oripavine
View the document4.6 Khat
View the document5. Terminology used in reporting abuse-related adverse drug reactions
View the document6. Other matters
View the documentAcknowledgements
View the documentReferences
View the documentAnnex Terminology used in reporting abuse-related adverse drug reactions

4.3 Zopiclone (INN)

Zopiclone, chemical name 4-methyl-1-piperazinecarboxylic acid ester with 6-(5-chloro-2-pyridyl)-6,7-dihydro-7-hydroxy-5H-pyrrolo[3,4-b]pyrazin-5-one, was pre-reviewed at the twenty-ninth meeting of the Committee in 1994 (10), which recommended continued surveillance, but not a critical review.

The pharmacological profile of zopiclone is similar to that of chlordiazepoxide. The pharmacological activity of zopiclone is believed to be related to its binding to the benzodiazepine receptor complex. Studies of abuse liability in animals and humans have indicated that zopiclone has some abuse potential together with the capacity to produce withdrawal syndrome upon its discontinuation. In terms of the number of adverse drug reaction reports related to abuse received by the international drug monitoring programme, zopiclone ranks higher than nitrazepam and temazepam. Furthermore, the Committee was informed that the government of Switzerland had submitted a formal notification to the United Nations concerning the scheduling of zopiclone.


In accordance with the Guidelines, the Committee recommended the critical review of zopiclone.

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