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Death may occur when GABAergic substances are combined with other depressants such as opiates, benzodiazepines, barbiturates, gabapentinoids, thienodiazepines or alcohol.[1]

It is strongly discouraged to combine these substances, particularly in common to heavy doses.

Summary sheet: Zopiclone
Chemical Nomenclature
Common names Zimovane, Imovane
Substitutive name Zopiclone
Systematic name (RS)-6-(5-Chloropyridin-2-yl)-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazin-5-yl 4-methylpiperazine-1-carboxylate
Class Membership
Psychoactive class Depressant / Hypnotic / Hallucinogen
Chemical class Cyclopyrrolone
Routes of Administration

WARNING: Always start with lower doses due to differences between individual body weight, tolerance, metabolism, and personal sensitivity. See responsible use section.

Bioavailability 52 - 59%[citation needed]
Threshold 2 - 3.5 mg
Light 3.5 - 5 mg
Common 5 - 7.5 mg
Strong 7.5 - 15 mg
Heavy 15 mg +
Total 3.5 - 9 hours
Onset 10 - 30 minutes

DISCLAIMER: PW's dosage information is gathered from users and resources for educational purposes only. It is not a recommendation and should be verified with other sources for accuracy.

Zopiclone (also known by the trade names Zimovane and Imovane) is a non-benzodiazepine hypnotic substance of the cyclopyrrolone class that is primarily used in the treatment of insomnia. Zopiclone is known to belong to a family of drugs colloquially known as "Z-drugs". Other Z-drugs include zaleplon (Sonata) and zolpidem (Ambien and AmbienCR).

Zopiclone is thought to increase the normal neurotransmission of the neurotransmitter GABA in the central nervous system in a similar yet distinct way to the activity of benzodiazepines. As zopiclone displays heavy sedating effects, it is has been approved for and is commonly sold as a sleeping pill.[citation needed]

While "Z-drugs" were initially thought to have less misuse potential than benzodiazepines, this appraisal has shifted somewhat in the last few years as a number of cases of addiction and habituation have been observed. Zopiclone, like all "Z-drugs", is recommended to be taken on a short-term basis -- usually a week or less.[2] Daily or continuous use of the drug is usually not advised.[3]


Zopiclone is a hypnotic nonbenzodiazepine drug of the cyclopyrrolone class. Zopiclone and its closely related dextrorotatory S-stereoisomer eszopiclone (Lunesta) are the most popular and available cyclopyrrolone drugs. This class of drugs is named for having a pyrrolone core, a five-membered ring with a nitrogen constituent (pyrrole) and a ketone group (-one).

The ketone group found in zopiclone is located at R5 of the pyrrolone ring. Zopiclone contains four nitrogenous rings including pyrrolone. Fused to the pyrrolone core is a pyrazine ring, a six-membered aromatic ring with two nitrogen substituents. The two rings are fused at R3 and R4. This bicylic core is called a pyrollopyrazine. Bound to the nitrogen group of the pyrrolone at R6 is a substituted pyridine ring. Pyridine is six-membered unsaturated ring with one nitrogen group. The pyridine ring of zopiclone is substituted at R5 with a chlorine group.

The final ring of zopiclone is a piperazine ring. Piperazine is a six-membered saturated ring with two nitrogen constituents; in this case, it is substituted at R4 with a methyl group. This piperazine ring is connected to the pyrrolone core of zopiclone at R7 through a carboxylate group.


Zopiclone, although structurally different from benzodiazepines, shares an almost identical pharmacological profile to them. Its mechanism of action works by binding to the same site as benzodiazepines and acts as a full agonist, which in turn positively modulates benzodiazepine-sensitive GABAA receptors and enhances GABA binding at the GABAA receptors to produce zopiclone's subjective effects.[citation needed] Since GABA functions as the brain's predominant inhibitory neurotransmitter, this activation of receptors results in the sedative and anxiolytic effects of zopiclone.[citation needed]

Subjective effects

In comparison to other substances of a similar nature such as benzodiazepines, zopiclone is commonly reported to present significantly more amnesic and disinhibiting effects in a manner similar to alcohol.

The effects listed below are based upon the subjective effects index and personal experiences of PsychonautWiki contributors. These effects should be taken with a grain of salt and will rarely (if ever) occur all at once, but heavier doses will increase the chances of inducing a full range of effects. Likewise, adverse effects become much more likely on higher doses and may include serious injury or death.

Physical effects

Visual effects

Cognitive effects

Experience reports

There are currently no anecdotal reports which describe the effects of this compound within our experience index. Additional experience reports can be found here:

Toxicity and harm potential

By itself, zopiclone likely has a low toxicity relative to dose. However, it is potentially lethal when mixed with depressants like benzodiazepines, alcohol or opioids. When combined with one or several of these drugs the already existing chance of a having a "black-out" is significantly increased, leaving the user with very little to no memory of the events that occurred whilst under the influence of zopiclone alone or combined with most other CNS depressants. Users have reported taking zopiclone in combination with alcohol in an attempt to treat hangovers with varying degrees of success.

It is strongly recommended that one use harm reduction practices when using this substance.

Lethal dosage

Zopiclone is capable of resulting in death at extremely high doses and is sometimes used as a method of suicide.[4][5] It has a similar fatality index as benzodiazepine drugs, apart from temazepam, which is particularly toxic in overdose.[6][7][8][9][10]

An overdose of zopiclone may present with excessive sedation and depressed respiratory function that may progress to coma and possibly death.[11] Zopiclone combined with alcohol, opiates, or other central nervous system depressants may be even more likely to lead to fatal overdoses. Zopiclone overdoses can be treated with the benzodiazepine receptor antagonist flumazenil, which displaces zopiclone from its binding site on the benzodiazepine receptor, thereby rapidly reversing its effects.[12][13] Serious effects on the heart may also occur from a zopiclone overdose[14][15] when combined with piperazine.[16]

Tolerance and addiction potential

Zopiclone is extremely physically and psychologically addictive. This compound may have an even greater addictive potential than benzodiazepines and has been described as a "benzodiazepine in disguise".[17][18][19]

Tolerance will develop to the sedative-hypnotic effects within a couple of weeks of daily use. After cessation, the tolerance returns to baseline in 7 - 14 days. Withdrawal symptoms or rebound symptoms may occur after ceasing usage abruptly following a few weeks or longer of steady dosing, and may necessitate a gradual dose reduction.

Zopiclone presents cross-tolerance with all benzodiazepines, meaning that after its consumption benzodiazepines and most other GABAgenic depressants will have a reduced effect.[20] Alcohol has cross tolerance with GABAA receptor positive modulators such as the benzodiazepines and the nonbenzodiazepine drugs. For this reason, alcoholics or recovering alcoholics may be at increased risk of physical dependence on zopiclone. It should be avoided in those with a history of alcoholism or drug misuse.

Discontinuation and withdrawal

Physical dependence, recreational abuse and withdrawal syndromes similar to those seen in benzodiazepine withdrawal are frequently encountered.[21] Due to the risk of tolerance and physical dependence, zopiclone is only recommended for short-term relief of insomnia, or alternatively, long-term infrequent use.[22] Abrupt withdrawal, particularly with prolonged and high doses, can (in severe cases) cause seizures and delirium.[23][24]Withdrawal symptoms included anxiety, tachycardia, tremors, sweats, flushes, palpitations, derealisation, and further insomnia.[25] Suspected withdrawal convulsions during detoxification from zopiclone have been reported, but the individual was a high-dose zopiclone misuser.[26]

If zopiclone has been taken for more than a few weeks, then the medication should be gradually reduced or preferably crossed over to an equivalent dose of diazepam (Valium) which has a much longer half-life, making withdrawal easier. One should then gradually taper the dose over a period of several months to avoid extremely severe and unpleasant withdrawal symptoms which can last up to two years after withdrawal if the withdrawal is done too abruptly.[27][28][29]

Dangerous interactions

Although many psychoactive substances are safe to use on their own, they can become dangerous or even life-threatening when taken with other substances. The list below contains some potentially dangerous combinations, but may not include all of them. Certain combinations may be safe in low doses but still increase the possibility of injury of death. Independent research should always be conducted to ensure that a combination of two or more substances is safe before consumption.

Legal status


This legality section is a stub.

As such, it may contain incomplete or wrong information. You can help by expanding it.

  • Australia: Zopiclone is available by prescription only.[citation needed]
  • United Kingdom: Zopiclone has been a class C drug since June 2014.[30] It is illegal to possess (without a legitimate prescription), supply, produce or import.
  • United States: On April 4, 2005, the U.S. Drug Enforcement Administration listed zopiclone under Schedule IV due to evidence that the drug has addictive properties similar to benzodiazepines.

See also

External links


  1. Risks of Combining Depressants (Tripsit) | https://tripsit.me/combining-depressants/
  2. http://www.nice.org.uk/nicemedia/pdf/TA077publicinfoenglish.pdf
  3. Effects of zopiclone and temazepam on sleep, behaviour and mood during the day (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/2744064
  4. Zopiclone fatality in a hospitalized patient (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/9068198
  5. Detection and quantification of the hypnotic zopiclone, connected with an uncommon case of drowning (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/8939015
  6. Relative toxicity of benzodiazepines in overdose (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/9068198
  7. Buckley NA, Dawson AH, Whyte IM, McManus P, Ferguson N.Correlations between prescriptions and drugs taken in self-poisoning: Implications for prescribers and drug regulation.Med J Aust (in press)
  8. Relative toxicity of benzodiazepines in overdose
  9. Analysis of zopiclone (Imovane) in postmortem specimens by GC-MS and HPLC with diode-array detection (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/8837952
  10. An autopsy case of poisoning by neuropsychopharmaceuticals including zopiclone (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/9893443
  11. Two cases of fatal zopiclone overdose (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/8868406
  12. Zopiclone overdose responsive to flumazenil (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/16235515
  13. Zopiclone poisoning: tissue distribution and potential for postmortem diffusion (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/8039775
  14. First-degree heart block caused by voluntary zopiclone poisoning (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/2353332
  15. Auriculo-ventricular block during voluntary poisoning with zopiclone (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/2814922
  16. Dart, Richard C. (2003). Medical Toxicology. p. 889. ISBN 978-0-7817-2845-4.
  17. Adverse effects of zopiclone (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/9656789
  18. Imovane--a benzodiazepine in disguise (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/8321452
  19. The role of liquid chromatography-tandem mass spectrometry (LC-MS/MS) to test blood and urine samples for the toxicological investigation of drug-facilitated crimes (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/18367985
  20. Zopiclone and triazolam in insomnia associated with generalized anxiety disorder: a placebo-controlled evaluation of efficacy and daytime anxiety (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/7862917
  21. Evaluation of zopiclone physical dependence liability in normal volunteers (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/6669632
  22. An assessment of short-acting hypnotics (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/8573298
  23. Hypnotic dependence: zolpidem and zopiclone too (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/11503851
  24. Zopiclone withdrawal: an unusual cause of delirium in the elderly (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/16107464
  25. Physical dependence on zopiclone: case reports (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/9462317
  26. Misuse of zopiclone and convulsions during withdrawal (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/1754610
  27. http://www.sanofi.ca/products/en/imovane.pdf
  28. A case of primary zopiclone dependence (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/11450624
  29. BENZODIAZEPINES: HOW THEY WORK AND HOW TO WITHDRAW | http://www.benzo.org.uk/manual/
  30. The Misuse of Drugs Act 1971 (Ketamine etc.) (Amendment) Order 2014 (Legislation.gov.uk) | http://www.legislation.gov.uk/uksi/2014/1106/contents/made