Zopiclone: What It Is and Why It Isn’t Sold in the US

If you have searched for zopiclone, you may have noticed something odd: most of the top US results are about a different drug, eszopiclone. That is not a mistake. Zopiclone is a widely used sleeping pill in Canada, the UK, Europe and elsewhere, but it has never been approved in the United States. Travelers, people who recently moved to the US, and anyone reading international health forums often end up confused about what zopiclone is, whether it is legal here, and what the American equivalent would be.

This guide explains what zopiclone is, how it works, how it compares with the medicines US doctors actually prescribe, what the FDA and DEA rules mean for you, and the safety warnings that apply to the whole drug family. It is written for general education, not as a substitute for advice from your own prescriber or pharmacist.

What is zopiclone?

Zopiclone is a hypnotic, meaning a medicine that helps you fall asleep and stay asleep. Chemically, it belongs to a group called cyclopyrrolones. It is one of three drugs commonly nicknamed the “Z-drugs,” along with zolpidem (Ambien) and zaleplon (Sonata). A review of Z-drug toxicology in the Journal of Medical Toxicology notes that zopiclone’s structure is unrelated to benzodiazepines, even though it acts on the same brain receptor.

In countries where it is sold, zopiclone is generally prescribed for short-term insomnia, often for no more than a few weeks at a time. Brand names abroad include Imovane and Zimovane. An older pharmacology review indexed on PubMed concluded that zopiclone works at least as well as many benzodiazepines for short-term insomnia, while noting that its long-term risk-benefit balance was less clear.

Racemic zopiclone and eszopiclone: one molecule, two forms

Many drug molecules come in two mirror-image forms, a bit like your left and right hands. Zopiclone is a “racemic” mixture, which means it contains equal amounts of both forms. Eszopiclone is just one of those forms, the (S)-form, which carries most of the sleep-promoting activity. The FDA-approved eszopiclone label on DailyMed describes eszopiclone as the S-isomer of racemic zopiclone.

So the two are close relatives, but they are not interchangeable milligram for milligram. They are separate products with different dosing, and switching between them is a decision for a prescriber.

Why zopiclone isn’t sold in the US

In the US, a prescription drug can only be marketed after the FDA approves it. Zopiclone was developed and launched in Europe and never went through FDA approval. Instead, a US company developed eszopiclone, which the FDA approved in 2004 under the brand name Lunesta. Generic eszopiclone tablets are now widely available.

There is a second layer: controlled-substance law. In April 2005, the DEA published a final rule in the Federal Register placing zopiclone into Schedule IV of the Controlled Substances Act. Because eszopiclone is a form of zopiclone, it is also regulated as a Schedule IV drug, which is why its label carries the C-IV symbol.

In practical terms, that means:

• You will not find zopiclone at a US pharmacy, and a US prescriber cannot prescribe an FDA-approved zopiclone product because none exists.
• Zopiclone is a federally controlled substance, so it is subject to DEA rules on top of FDA rules.
• Eszopiclone, the approved relative, requires a valid prescription and is subject to Schedule IV limits on refills.

The FDA warns that medicines from outside the legitimate drug supply chain do not carry the same assurance of safety, quality and effectiveness. If you were prescribed zopiclone in another country and are now living in or visiting the US, the safest step is to talk with a US-licensed clinician before you run out, so they can review your sleep problem and discuss approved options.

How zopiclone works

Your brain has a built-in “calming” chemical called GABA (gamma-aminobutyric acid). GABA works by attaching to GABA-A receptors on nerve cells and quieting their activity. Zopiclone, like other Z-drugs and benzodiazepines, makes those receptors respond more strongly to GABA, which leads to drowsiness and sleep.

The Journal of Medical Toxicology review explains that zopiclone shows a preference for receptors containing the alpha-1 subunit, the part most linked to sedation. It also has the longest action of the Z-drugs, comparable with some short-acting benzodiazepines. That longer action helps people stay asleep, but it also raises the chance of feeling groggy the next morning.

How long zopiclone lasts compared with other Z-drugs

The table below summarizes typical values reported in that review. Half-life is the time it takes the body to clear half of a dose; longer half-lives tend to mean more “hangover” risk.

Medicine	US status	Time to peak level	Typical half-life	Main liver enzyme
Zopiclone	Not FDA-approved; Schedule IV	1.5 to 2 hours	5 to 6 hours	CYP3A4, CYP2C8
Eszopiclone (Lunesta)	FDA-approved; Schedule IV	1 to 1.5 hours	About 6 hours (about 9 in adults 65+)	CYP3A4, CYP2E1
Zolpidem (Ambien)	FDA-approved; Schedule IV	1 to 2 hours	2.5 to 3 hours	CYP3A4 and others
Zaleplon (Sonata)	FDA-approved; Schedule IV	Under 1.5 hours	About 1 hour	Aldehyde oxidase, CYP3A4

Because zopiclone is broken down mainly by the liver enzyme CYP3A4, medicines that block or speed up that enzyme can change how much drug is in your blood. The eszopiclone label, for example, limits the dose when it is combined with strong CYP3A4 blockers such as ketoconazole.

Zopiclone vs eszopiclone at a glance

	Zopiclone	Eszopiclone (Lunesta)
What it is	Mixture of both mirror-image forms	Only the active (S)-form
FDA approval	None	Approved for insomnia (2004)
DEA schedule	Schedule IV	Schedule IV
Where available	Canada, UK, Europe and other countries	US pharmacies with a prescription
Signature side effect	Bitter or metallic taste	Unpleasant taste
US boxed warning	Not applicable (not marketed)	Complex sleep behaviors

What the US eszopiclone label says about dosing

According to the FDA-approved eszopiclone label, the recommended starting dose for adults is 1 mg taken immediately before bed, with at least 7 to 8 hours left before you plan to wake up. A prescriber may raise it if needed, to a maximum of 3 mg once a night. For older or debilitated adults, people with severe liver impairment, and people taking strong CYP3A4 inhibitors, the maximum is 2 mg. Never adjust a dose on your own.

Zopiclone side effects and safety concerns

The side effect people most often remember with zopiclone is taste. The Journal of Medical Toxicology review reports a bitter or unpleasant taste in roughly 10 to 35 percent of people taking zopiclone or eszopiclone, depending on dose, sometimes enough that people stop the medicine. In US trials summarized on the eszopiclone label, unpleasant taste affected 17 percent of adults on 2 mg and 34 percent on 3 mg, compared with 3 percent on placebo.

Other common effects reported for this drug family include:

• Drowsiness, dizziness or grogginess the next day
• Headache
• Dry mouth
• Memory problems for the period after a dose

Next-day impairment and driving

Zopiclone has the longest half-life of the Z-drugs, and the toxicology review links that to a greater chance of “residual” effects the next day. The US eszopiclone label warns that people taking 3 mg should not drive or do other tasks that need full alertness the day after use, and that impairment can be present even when you feel fully awake. If you take any sleep medicine, plan for a full night in bed and be cautious with driving the next morning.

Complex sleep behaviors and the FDA boxed warning

In April 2019, the FDA required its strongest warning, a boxed warning, on eszopiclone, zaleplon and zolpidem. The FDA safety communication describes rare but serious injuries and deaths from complex sleep behaviors: sleepwalking, sleep-driving and doing other activities while not fully awake, often with no memory afterward. The FDA also told clinicians not to prescribe these drugs to people who have had such an episode before.

Zopiclone was not part of that action only because it is not marketed in the US. It belongs to the same drug family, and similar behaviors have been reported with it.

Tolerance, dependence and withdrawal

Z-drugs were once thought to be almost free of dependence risk. Experience has shown otherwise. The toxicology review notes that tolerance, dependence and withdrawal are all reported with Z-drugs, though usually less often and less severely than with traditional benzodiazepines. MedlinePlus advice on eszopiclone says not to stop suddenly after long-term use without talking to your doctor, who will usually lower the dose gradually. Rebound insomnia, where sleep briefly gets worse after stopping, can also happen.

Who should be especially careful

• Adults 65 and older. Sleep medicines raise the risk of falls and confusion. MedlinePlus notes that older adults should usually not take eszopiclone because other options may be safer.
• People with breathing problems. This includes sleep apnea and chronic lung disease, since sedatives can weaken breathing.
• People with liver disease. The drug may build up in the body.
• Anyone with a history of depression or substance use. Mood changes and misuse are reported with this drug class.
• People who are pregnant or breastfeeding. Talk with your prescriber before using any sleep medicine.

Alcohol and other medicines

Alcohol adds to the sedating effects of zopiclone and eszopiclone, and MedlinePlus advises avoiding it. The same caution applies to other central nervous system depressants, such as opioid pain medicines, benzodiazepines, some antihistamines, and cannabis. Combining them can deepen sedation and slow breathing. Always give your prescriber and pharmacist a complete list of what you take, including over-the-counter sleep aids and supplements.

Safer first steps for insomnia in the US

Whether you used zopiclone abroad or are simply comparing options, it helps to know that US guidelines do not put sleeping pills first. In 2016, the American College of Physicians published a guideline recommending cognitive behavioral therapy for insomnia (CBT-I) as the first treatment for adults with chronic insomnia. CBT-I combines:

• Changing unhelpful thoughts and worries about sleep
• Stimulus control, such as using the bed only for sleep
• Sleep restriction, a structured way to consolidate sleep
• Sleep hygiene education

CBT-I can be delivered in person, in groups, by phone, through web programs or with self-help books. If it does not help enough, the ACP advises that patients and clinicians decide together whether to add a medicine, weighing benefits, harms and costs. The ACP also notes that FDA-approved sleep medicines are intended for short-term use and that doctors should look for treatable causes of poor sleep, such as depression, pain, sleep apnea or restless legs.

If medicine is appropriate, a US prescriber may consider eszopiclone or another FDA-approved option suited to your health, age and other medicines.

Questions to ask your prescriber

• I used zopiclone in another country. Is eszopiclone or something else the right choice for me in the US?
• Could something else be causing my insomnia, such as sleep apnea, pain, mood or a medicine I take?
• Can you refer me to CBT-I, or recommend a program I can use at home?
• How long should I take a sleep medicine, and how will we stop it safely?
• Do any of my current medicines, including over-the-counter products, interact with it?
• Is it safe for me to drive the morning after a dose?

Frequently asked questions

Is zopiclone legal in the US?

Zopiclone is not FDA-approved, so it is not sold in US pharmacies. The DEA lists it as a Schedule IV controlled substance. Talk with a US-licensed clinician about approved options instead.

What is the US equivalent of zopiclone?

The closest US medicine is eszopiclone (Lunesta), the active single form of the zopiclone molecule. It is FDA-approved for insomnia, but its dosing differs from zopiclone, so a prescriber should decide whether it fits you.

Is zopiclone a benzodiazepine?

No. Zopiclone is a cyclopyrrolone, a “Z-drug.” It acts on the same GABA-A receptors as benzodiazepines, so it shares some of their risks, including next-day drowsiness and dependence.

Why does zopiclone leave a bitter or metallic taste?

A bitter or unpleasant taste is the best-known side effect of zopiclone and eszopiclone, reported in roughly 10 to 35 percent of users depending on dose. Tell your prescriber if it is bothersome.

How long does zopiclone stay in your system?

Zopiclone has a typical half-life of about 5 to 6 hours, the longest of the Z-drugs, which is why next-morning grogginess is more likely than with shorter-acting options.

Related guides

• Tapentadol (Nucynta): Uses, How It Works and Safety

Sources

1. Drug Enforcement Administration. Schedules of Controlled Substances: Placement of Zopiclone Into Schedule IV. Federal Register, April 4, 2005 (govinfo.gov).
2. Eszopiclone tablets, film coated: Prescribing information. DailyMed, US National Library of Medicine.
3. US Food and Drug Administration. Certain prescription insomnia medicines: New boxed warning due to risk of serious injuries caused by complex sleep behaviors. April 30, 2019.
4. US Food and Drug Administration. Human Drug Imports.
5. Gunja N. The Clinical and Forensic Toxicology of Z-drugs. Journal of Medical Toxicology, 2013 (PubMed Central).
6. Zopiclone: An update of its pharmacology, clinical efficacy and tolerability in the treatment of insomnia. Drugs, 1998 (PubMed).
7. MedlinePlus. Eszopiclone. US National Library of Medicine.
8. American College of Physicians. ACP Recommends Cognitive Behavioral Therapy as Initial Treatment for Chronic Insomnia. May 3, 2016.