Eszopiclone

(S)-6-(5-Chloro-2-pyridinyl)-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazin-5-yl-4-methyl-1-piperazinecarboxylate

Lunesta, Eszop

Psychoactive Class

Chemical Class

Eszopiclone is a nonbenzodiazepine hypnotic of the cyclopyrrolone class and the active S-stereoisomer of zopiclone.¹ It belongs to the family of drugs colloquially known as "Z-drugs." First approved by the FDA in 2004 for the treatment of insomnia,¹ it is notable for being one of few hypnotic sedatives approved for long-term use.² Eszopiclone enhances GABAergic neurotransmission in a manner similar to yet distinct from benzodiazepines¹ and is considered habit-forming.¹

Dosage & Duration

Dosage

Threshold~0.5 mg

Light1-2 mg

Moderate2-3 mg

Strong3-6 mg

Heavy6+ mg

Duration

Onset10-20 minutes

Peak0.5-1.5 hours

Total6-8 hours

Half-life

~6 hours

Subjective Effects

The experience is dominated by rapid-onset sedation that typically leads directly into sleep, with pronounced physical relaxation and reduced anxiety. Users who resist the initial wave of sleepiness and remain awake may encounter hallucinatory effects, including basic closed- and open-eye visuals, alongside an emotionally numbed and disinhibited headspace. Memory of the period after ingestion is often unreliable, and residual impairment of coordination and alertness can persist into the following morning, particularly at higher doses.

Physical

Heavy sedation, muscle relaxation, and loss of motor coordination dominate the physical experience, sometimes accompanied by dizziness, headache, nausea, and dry mouth. Complex sleep behaviors such as sleep-walking have been reported.

Sedation

Sedation is the core physical effect, arriving quickly and strongly encouraging sleep. It is accompanied by muscle relaxation and impaired coordination.

Uncomfortable

Dizziness Headache Nausea Dry mouth

Cognitive

The headspace is sedated, emotionally blunted, and disinhibited, with anterograde amnesia commonly leaving partial or absent recall of events after ingestion.

Suppressions

The mental state is defined by suppression: thought, emotion, anxiety, and memory formation are all dampened as sedation takes hold.

Visual

Visual effects are not typical at standard hypnotic doses unless the user remains awake past the onset of sleepiness, at which point basic hallucinatory visuals can appear. Hallucinations become more frequent at doses well above the therapeutic range.

Hallucinatory States

Reagent Testing

Loading reagent data

Expected colorimetric results are being prepared.

Pharmacology

Pharmacodynamics

Eszopiclone acts as a positive allosteric modulator at GABA-A receptors, binding at the benzodiazepine site with full agonist efficacy.¹ It shows particular affinity for receptors containing α1, α3, and α5 subunits, with additional modulatory activity at α2-containing receptors. This binding enhances GABA-mediated inhibitory signaling by increasing the frequency of chloride channel opening in the presence of endogenous GABA. Eszopiclone also acts as an agonist at the translocator protein (TSPO).

Pharmacokinetics

Eszopiclone is rapidly absorbed after oral administration, with peak plasma concentrations reached within approximately 0.45 to 1.3 hours.¹ It is 52–59% bound to plasma proteins¹ with a volume of distribution of approximately 90 L. The drug undergoes extensive hepatic metabolism via oxidation and demethylation, primarily mediated by CYP3A4 with additional contributions from CYP2C8 and CYP2E1.¹ The major metabolites are S-desmethylzopiclone, which retains pharmacological activity, and zopiclone-N-oxide, which shows only weak activity.¹ The elimination half-life is approximately 6 hours in healthy individuals but is prolonged in those with hepatic impairment, in elderly patients, and when co-administered with CYP3A4 inhibitors.¹ Less than 10% of an oral dose is excreted in the urine as the parent compound, with the majority eliminated as metabolites.¹

Interactions

Dangerous

Highest risk

These combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.

Dissociatives

Caution

Use caution

These combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.

1,2-BenzodiazepineAbacavirAbametapirAbataceptAbiraterone

TripSit

Tolerance

Full Tolerance

Tolerance to sedative-hypnotic effects can build after roughly several weeks of everyday use. Eszopiclone may carry a stronger addiction liability than benzodiazepines.

Cross Tolerance

Benzodiazepines, GABAergic depressants

Baseline Reset

Tolerance returns to baseline within 7-14 days after cessation of use. However, if the substance has been used for extended periods, a gradual tapering process is recommended to avoid severe withdrawal symptoms that can persist for extended durations.

Harm Potential

Addiction & Dependence

Psychological

Moderate

Psychological dependence can develop with regular use. Compulsive redosing has been reported as a notable effect. Abuse potential exists, particularly in individuals with a history of substance use disorders, with studies showing eszopiclone produces effects similar to diazepam at supratherapeutic doses.¹ Use beyond short-term periods is generally not recommended.

Physical

High

Physical dependence develops after a few weeks of regular dosing. Withdrawal symptoms or rebound effects occur following abrupt cessation and can persist for extended periods if not properly managed through gradual tapering.¹ Cross-tolerance exists with benzodiazepines, and transitioning to a longer-acting benzodiazepine for tapering is recommended to avoid severe withdrawal.¹

Toxicity

Immune System

A meta-analysis found a 44% higher rate of mild infections such as pharyngitis or sinusitis in users of eszopiclone and other hypnotic drugs compared to placebo; this appears to be a class effect of sedative-hypnotics rather than specific to eszopiclone.³

Psychosis Risk

Hallucinations, delusions, and delirium can occur, particularly at doses exceeding recommended amounts or when users resist the urge to sleep.¹ Visual phenomena including shadow people and auditory hallucinations are reported at higher doses, with effects described as similar to but less pronounced than those of deliriants.

History & Culture

Development and Approval

Eszopiclone represents the isolated S-stereoisomer of zopiclone, a cyclopyrrolone sedative-hypnotic that had been available in Europe since 1989. The development of eszopiclone as a distinct pharmaceutical product was undertaken by Sepracor, who marketed the compound under the brand name Lunesta.…

Legality

By Country

United StatesSchedule IV

Classified as a Schedule IV controlled substance under the Controlled Substances Act.¹ Approved by the FDA on December 15, 2004 for the treatment of insomnia.¹² The scheduling reflects recognized abuse potential comparable to benzodiazepines.¹ Possession without a valid prescription may result in drug charges.

CanadaPrescription medication

Available as a prescription medication under the brand name Lunesta. Marketing authorization was granted in October 2020.¹¹ Requires a prescription for lawful possession.¹¹

References

Source Pages

Citations

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Eszopiclone

(S)-6-(5-Chloro-2-pyridinyl)-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazin-5-yl-4-methyl-1-piperazinecarboxylate

Lunesta, Eszop

Psychoactive Class

Depressant Hallucinogen

Chemical Class

Cyclopyrrolone