Zopiclone Side Effects: Common and Serious Symptoms

Zopiclone is a prescription-only sleeping medicine used for the short-term treatment of insomnia in adults. Like all medicines, it can cause side effects. Many are mild and temporary, but some symptoms require prompt medical attention. Understanding the possible effects can help you use zopiclone more safely and know when to contact a healthcare professional.

Important: This article is for general information only. It does not replace advice from a GP, pharmacist or other qualified healthcare professional.

What is zopiclone?

Zopiclone is a hypnotic medicine, sometimes called a “Z-drug”. It works by reducing certain activity in the brain, helping promote sleepiness and making it easier for some people to fall asleep or stay asleep.

Zopiclone is usually prescribed for a short period when insomnia is severe, distressing or affecting daily life. It is not intended as a long-term solution for ongoing sleep problems. Continued insomnia may require an assessment of possible causes such as anxiety, depression, pain, breathing disorders, medicines, caffeine or irregular sleep patterns.

Because zopiclone can cause drowsiness, impaired coordination, dependence and withdrawal symptoms, it should be taken only as prescribed.

Common side effects of zopiclone

Some people experience mild side effects, particularly when they first begin treatment. Common symptoms may include:

• A bitter, metallic or unpleasant taste.

• Dry mouth.

• Drowsiness or tiredness the following day.

• Dizziness or light-headedness.

• Headache.

• Reduced concentration.

• Memory difficulties.

• Feeling weak or less coordinated.

• Nausea or indigestion.

• Unusual dreams or nightmares.

These effects may become less noticeable as the body adjusts, but they should still be discussed with a pharmacist or prescriber if they are persistent or troublesome.

Bitter or metallic taste

A bitter or metallic taste is one of the commonly reported effects of zopiclone. It may remain for several hours after taking a tablet. Drinking water or maintaining good oral hygiene may help, but speak with a pharmacist if the symptom is severe or does not improve.

Dry mouth

Zopiclone may reduce saliva production and cause a dry or sticky feeling in the mouth. Regular sips of water and sugar-free chewing gum may provide relief. If dry mouth continues, ask a pharmacist for advice because persistent dryness can affect dental health.

Drowsiness and tiredness

Zopiclone is intended to cause sleepiness, but its effects can continue into the next morning. You may feel tired, slowed down or less alert after waking.

Do not drive, cycle, operate machinery or perform tasks requiring concentration if you feel drowsy, dizzy or impaired. The risk may be higher if you take the medicine late at night, sleep for less than seven or eight hours or use alcohol or other sedating medicines.

Dizziness and reduced coordination

Dizziness, unsteadiness and reduced coordination can increase the risk of falls. Take extra care when getting out of bed, especially at night. Older adults may be more vulnerable to falls and confusion.

Avoid alcohol because it can intensify dizziness and sedation.

Memory and concentration problems

Zopiclone may affect short-term memory, attention and concentration. These effects may be more noticeable with higher doses, insufficient sleep or combinations with alcohol and other sedatives.

Tell your prescriber if memory or concentration problems affect work, driving or daily activities.

Serious symptoms requiring medical advice

Some reactions are uncommon but require prompt assessment. Contact a healthcare professional if you experience:

• Severe confusion or disorientation.

• Hallucinations.

• Extreme agitation or aggressive behaviour.

• Worsening depression.

• Suicidal thoughts.

• Severe allergic symptoms.

• Unusual activity while not fully awake.

• Signs of dependence or withdrawal.

• Severe or persistent breathing difficulties.

Severe allergic reaction

Seek urgent medical help if you develop:

• Swelling of the lips, mouth, tongue or throat.

• Difficulty breathing or swallowing.

• A widespread rash, blistering or peeling skin.

• Sudden faintness or collapse.

These symptoms may indicate a serious allergic reaction. Call 999 if breathing is affected or the person becomes unresponsive.

Breathing problems

Zopiclone can cause dangerous sedation and breathing difficulties, especially when combined with alcohol, opioid painkillers, tranquillisers or other medicines that cause drowsiness.

Call 999 if someone taking zopiclone is difficult to wake, has slow or shallow breathing, becomes unconscious or develops blue or grey lips.

People with sleep apnoea, respiratory disease or other breathing problems should tell their prescriber before taking zopiclone.

Severe confusion or hallucinations

Confusion, hallucinations, paranoia or unusual behaviour should be reported promptly. These reactions may be more likely in older adults or when zopiclone is combined with alcohol or other sedating medicines.

Do not take another dose until you have obtained medical advice if you develop a serious or unexpected mental or behavioural reaction.

Unusual sleep-related behaviour

Some people may carry out activities while not fully awake and have little or no memory afterwards. This may include:

• Walking around.

• Preparing or eating food.

• Making phone calls.

• Leaving the house.

• Driving or other complex activity.

Stop taking zopiclone and contact your prescriber promptly if this occurs. Alcohol and sleep deprivation may increase the risk.

Dependence, tolerance and withdrawal

Zopiclone can cause physical dependence, psychological dependence, tolerance and addiction. Dependence means that the body or mind becomes used to the medicine, and symptoms may occur when the dose is reduced or stopped.

Possible withdrawal symptoms include:

• Anxiety.

• Restlessness.

• Irritability.

• Sweating.

• Shaking.

• Headache.

• Disturbed sleep.

• Rebound insomnia.

• Difficulty concentrating.

• Confusion or unusual perceptions.

The risk is generally higher with larger doses and longer treatment, but dependence can occur even when zopiclone is taken as prescribed.

Do not stop regular treatment suddenly without medical advice. A prescriber may recommend a gradual dose reduction to reduce withdrawal symptoms.

Who may have a higher risk of side effects?

Some people may be more sensitive to zopiclone or require additional monitoring. Tell your prescriber if you:

• Are aged 65 or over.

• Have liver or kidney problems.

• Have breathing difficulties or sleep apnoea.

• Have a history of depression or another mental health condition.

• Have experienced alcohol, medicine or recreational drug dependence.

• Take opioid painkillers or other sedating medicines.

• Are pregnant, planning pregnancy or breastfeeding.

• Have myasthenia gravis or another condition causing muscle weakness.

Older adults may experience increased drowsiness, dizziness, confusion and falls. A clinician may prescribe a lower strength or consider another treatment.

Medicines and substances that may increase side effects

Tell your prescriber or pharmacist about all medicines, supplements and recreational substances you use. Particular caution may be needed with:

• Alcohol.

• Opioid painkillers.

• Other sleeping tablets.

• Tranquillisers and anti-anxiety medicines.

• Sedating antihistamines.

• Some antidepressants.

• Antipsychotic medicines.

• Medicines that cause dizziness or drowsiness.

Do not combine zopiclone with another sedating product unless a healthcare professional has specifically advised you to do so.

How to reduce the risk of side effects

Use zopiclone only according to your prescription. Safer-use measures include:

• Take the prescribed dose shortly before bedtime.

• Ensure you can sleep for approximately seven to eight hours.

• Do not take an additional dose during the same night.

• Avoid alcohol during treatment.

• Do not use recreational drugs or unapproved sedatives.

• Do not drive if you feel sleepy, dizzy or less alert.

• Keep the medicine away from children and other people.

• Do not share your tablets.

• Do not increase the dose if the medicine seems less effective.

• Do not stop regular treatment suddenly without professional advice.

If insomnia continues, arrange a review rather than extending treatment independently.

What should you do if side effects occur?

For mild symptoms, contact a pharmacist or prescriber if they persist, become troublesome or interfere with daily life. Keep a note of when the symptoms occur and whether they follow a dose change or combination with another medicine.

For serious symptoms, seek urgent medical assistance. Call 999 for difficulty breathing, loss of consciousness, severe allergic symptoms or a person who cannot be woken normally.

If you have taken more zopiclone than prescribed, seek urgent medical advice even if you initially feel well. Do not drive yourself. Keep the packaging available so healthcare professionals can identify the medicine and strength.

Frequently asked questions

Key points to remember

Zopiclone side effects range from mild symptoms such as dry mouth, bitter taste and next-day tiredness to serious reactions involving breathing, consciousness or behaviour.

Use zopiclone only as prescribed, avoid alcohol and other sedatives, allow enough time for sleep and do not drive if you feel impaired. Seek urgent help for breathing difficulties, severe allergic symptoms, loss of consciousness or extreme confusion.