Like all medicines, zopiclone can cause side effects — although not everyone gets them. Knowing which effects are common and harmless, and which need medical attention, helps you use the medicine safely and confidently.
Common side effects
These affect more than 1 in 100 people and usually settle as your body adjusts or once the course ends:
- A bitter or metallic taste in the mouth — the most frequently reported effect. It is harmless; sugar-free gum and drinking plenty of water can help.
- Dry mouth.
- Feeling sleepy or tired the next day. If this happens, do not drive, cycle or use tools or machinery, and mention it to your prescriber — a lower dose may suit you better.
Serious side effects — contact your GP or NHS 111
These are uncommon, but stop taking zopiclone and get medical advice promptly if you experience:
- Memory loss (amnesia) around the time of taking the tablet.
- Seeing or hearing things that are not there (hallucinations).
- Falls — a particular risk for older adults.
- Sleepwalking, or doing things such as eating, making calls or even driving while not fully awake, with no memory of it afterwards.
- Low mood, or thoughts of harming yourself. If you have thoughts of suicide or self-harm, contact your GP urgently, call NHS 111, or call Samaritans free on 116 123 at any time.
Emergency — call 999
Call 999 or go to A&E immediately if:
- You or someone else has signs of a serious allergic reaction: swelling of the lips, face, tongue or throat; wheezing; tightness in the chest; or a rash that spreads quickly.
- Someone has taken more zopiclone than prescribed, is very drowsy, or cannot be woken. Take the medicine packet with you if you can.
Why alcohol makes everything worse
Alcohol multiplies zopiclone’s sedative effect and dramatically raises the risk of dangerously deep sleep, breathing problems and sleepwalking behaviours. The safe amount of alcohol with zopiclone is none. Read our full guide: zopiclone and alcohol.
Reporting side effects
You can report any suspected side effect to the UK’s Yellow Card Scheme (search “MHRA Yellow Card”), which helps make medicines safer for everyone. Our pharmacists can help you file a report.
Frequently asked questions
What is the most common side effect of zopiclone?
A bitter or metallic taste in the mouth. It is harmless, caused by the medicine passing into saliva, and disappears after the course ends. Water and sugar-free gum can help.
Does zopiclone cause weight gain?
Weight gain is not a recognised common side effect of zopiclone. If you notice unexplained weight change while taking it, speak to your GP, as another cause is more likely.
Can zopiclone cause sleepwalking?
Rarely, yes — zopiclone can cause sleepwalking and doing activities while not fully awake, with no memory afterwards. The risk is higher with alcohol or other sedatives. If it happens, stop taking it and contact your GP.
How do I report a side effect?
Use the MHRA Yellow Card Scheme (online or via the Yellow Card app), or ask a pharmacist to help you file a report. Reporting helps make medicines safer for everyone.
Questions about your sleep medication? Speak to one of our pharmacists — advice is free and confidential. If you already have a prescription, you can nominate our pharmacy to dispense and deliver it.
This article is general health information based on NHS and BNF guidance. It is not medical advice, and it is not an advertisement for a prescription-only medicine. Zopiclone is available only on prescription in the UK and cannot be purchased from this website. Always follow your prescriber’s instructions and read the patient information leaflet. If you need urgent help call NHS 111; in an emergency call 999. [Clinical review placeholder — reviewed by NAME, Superintendent Pharmacist, GPhC reg. NUMBER, on DATE.]