Quick Answer: The most common zopiclone side effects are a bitter or metallic taste, dry mouth and daytime drowsiness. The one Health Canada acted on is next-day impairment: a 7.5 mg dose can affect driving up to 11 hours later, even when you feel alert. Serious effects like memory gaps and sleep behaviours are rarer but real.
Zopiclone side effects range from the famous metallic taste, reported by a large share of users, to next-day impairment serious enough that Health Canada rewrote the dosing rules in 2014. Zopiclone (brand name Imovane) is Canada's most-dispensed prescription sleep aid, and this guide walks through its side effect profile the way the Canadian product monograph lays it out: the common and annoying, the dose-related, and the rare-but-serious. Mattress Miracle in Brantford, Ontario is a sleep store, not a clinic; we publish this because customers ask, and we translate the official documents rather than replace them. Anything on this page that worries you belongs in a conversation with your pharmacist, who can see your full medication picture.
"The taste is what people volunteer first, every time. Second is some version of 'I am groggy until ten in the morning.' What almost nobody has been told is that the groggy feeling and actual impairment are not the same thing, you can be impaired without feeling it. That one fact from the Health Canada review changed how I answer when customers mention early-morning driving."
Talia Grose, sleep specialist, Mattress Miracle
In This Guide
Reading Time: 7 minutes
What are the most common zopiclone side effects?
The Canadian monograph lists taste alteration as the leading complaint: a bitter or metallic taste that starts after the dose and can linger through the next day. It happens because zopiclone is secreted into saliva. Behind it come dry mouth, daytime drowsiness, and dizziness or lightheadedness. Most of these are dose-related, one reason the recommended starting dose in Canada dropped to 3.75 mg (the details live in our zopiclone dosage guide). The taste has no reliable fix; staying hydrated helps some people, and it fades after the medication is stopped.
Next-day impairment: the side effect Health Canada acted on
Next-day impairment means measurable reduction in alertness, coordination and driving performance the morning after an evening dose (our guide to how long zopiclone stays in your system maps the full timeline). Health Canada's summary safety review found impairment up to 11 hours after a 7.5 mg dose, and, critically, that it can be present when you feel fully awake. The label's rule is blunt: do not drive or do hazardous work until you know how your dose affects you, and expect the risk to be higher for seniors and anyone with reduced liver or kidney function, where the drug clears more slowly. Studies indicate this residual effect is the mechanism behind Z-drug-associated falls and fractures in older adults, which is why geriatric dosing sits at the bottom of the range.
Alcohol multiplies everything
The monograph warns against combining zopiclone with alcohol or other sedating substances: the central nervous system effects add together, deepening sedation and impairment unpredictably. The same caution applies to other sedatives, some antidepressants, and opioid medications. This is exactly the interaction review a pharmacist runs; nothing on this page is medical advice, and your own medication list changes the answers.
Rare but serious effects: memory, behaviour, mood
Three families of rare effects earn the monograph's strongest language. Memory effects: anterograde amnesia, gaps covering events after the dose, more likely if sleep is interrupted early. Complex sleep behaviours: walking, eating, even driving while not fully awake, without memory of it; the guidance is to stop the medication and call your doctor if this occurs. And mood or behaviour changes, including worsening depression in susceptible people. These are uncommon, and they are the reasons the drug is prescription-only with a short intended course. If any of them show up, that is a same-week doctor conversation, not a wait-and-see.
Long-term side effects and dependence
Long-term zopiclone use raises two concerns the short-term label was designed to avoid. Tolerance: the same dose doing less over time, inviting dose creep. And dependence: rebound insomnia, sometimes with anxiety, when stopping after extended nightly use, which convinces people they still need the pill and closes the loop. The UBC Therapeutics Initiative's 2025 prescribing review flags exactly this pattern in Canadian practice and recommends short courses with a taper plan for anyone on it long-term. Weight gain, a common search worry, is not a prominent monograph effect; appetite changes are occasionally reported, and persistent weight change on any sleep medication deserves a doctor's look at the whole picture. The exit path from long-term use is a supervised taper through your prescriber, never a cold stop.
Reducing side effects safely
The levers that reduce zopiclone side effects are all in the label. Lowest effective dose, and in Canada that starts at 3.75 mg. A full 7 to 8 hour sleep opportunity after taking it, no exceptions. No alcohol. No middle-of-the-night re-dosing. Short courses with a defined end date. And in parallel, working the non-drug side so the medication has less to do: the technique library in our Insomnia Help hub and the fundamentals in our sleep hygiene guide are the evidence-backed route, and they have no next-day impairment.
The showroom perspective
Mattress Miracle has fitted beds in Brantford since 1997, and the side-effect stories customers share almost always end with the same question: how do I need this less? Our honest lane is the environment half: if pressure points, overheating or a sagging surface cause the wake-ups, fixing that is one less job for the medication. Come by 441 1/2 West Street or call (519) 770-0001; the sleep-environment audit costs nothing and our team is non-commission.
Frequently Asked Questions
Why does zopiclone leave a metallic taste?
The drug is secreted into saliva after absorption, so the taste comes from the medication itself, not the tablet coating. It is the most-reported side effect in the Canadian monograph, it is harmless, and it resolves once the medication is stopped.
Can I drive the morning after taking zopiclone?
Health Canada's review found driving impairment up to 11 hours after a 7.5 mg dose, sometimes without feeling impaired. The label says do not drive until you know how your dose affects you; for higher doses and early mornings, the safe reading is to arrange around it.
Does zopiclone cause weight gain?
Weight gain is not a prominent effect in the Canadian monograph. Appetite changes are occasionally reported, and long-term poor sleep itself affects weight. If you notice persistent change, bring it to your doctor rather than assuming the medication.
What should I do about side effects that scare me?
For sleep behaviours you do not remember, memory gaps, or mood changes: contact your doctor promptly, per the monograph's own guidance. For everything else, your pharmacist can tell you what is expected, what is dose-related, and what warrants a prescriber visit. Never stop abruptly after long-term use.
Visit Our Brantford Showroom
Mattress Miracle
441 1/2 West Street, Brantford
Phone: (519) 770-0001
Hours: Mon-Wed 10-6, Thu-Fri 10-7, Sat 10-5, Sun 12-4
Want the medication doing less of the work? Let us check whether your mattress is causing the wake-ups. Honest answers, no pressure, from the team that has done this since 1997.
Related Reading
- Zopiclone in Canada: the complete plain-language guide
- Imovane vs generic zopiclone
- Sleep aids in Canada: every option compared
Sources
- Imovane (zopiclone) Product Monograph, Sanofi-Aventis Canada: pdf.hres.ca
- Health Canada Summary Safety Review, next-day impairment: dhpp.hpfb-dgpsa.ca
- UBC Therapeutics Initiative, Letter 158 (2025): ncbi.nlm.nih.gov