Clonazepam: medicine to control seizures or fits, muscle spasms and restless legs syndrome - NHS

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Clonazepam

On this page

  1. About
  2. Key facts
  3. Who can and cannot take clonazepam
  4. How and when to take it
  5. Side effects
  6. How to cope with side effects
  7. Pregnancy and breastfeeding
  8. Cautions with other medicines
  9. Common questions

1. About

Clonazepam belongs to a group of medicines called benzodiazepines.

It's used to control seizures or fits due to epilepsy, involuntary muscle spasms, panic disorder and sometimes restless legs syndrome.

Clonazepam is available on prescription only. It comes as tablets and as a liquid that you swallow.

2. Key facts

  • Clonazepam works by increasing levels of a calming chemical in your brain. This can relieve anxiety, stop seizures and fits or relax tense muscles.
  • The most common side effect is feeling sleepy (drowsy) during the daytime.
  • Clonazepam is not likely to be addictive if you take it for a short time (2 to 4 weeks).
  • If you take clonazepam for more than 2 to 4 weeks, your dose will need to be reduced gradually before you stop taking it.
  • Do not drink alcohol while taking clonazepam. There's a risk you can sleep very deeply and you may have trouble waking up.

3. Who can and cannot take clonazepam

Clonazepam tablets and liquid can be taken by adults aged 18 years and over.

It can also be taken by children from 1 month old for epilepsy.

It's not suitable for everyone.

To make sure it's safe for you, tell your doctor before starting clonazepam if you:

  • have had an allergic reaction to clonazepam or any other medicine in the past
  • have myasthenia gravis, a condition that causes muscle weakness
  • have sleep apnoea, a condition that causes breathing problems when you're asleep
  • have lung, liver or kidney problems
  • have spinal or cerebellar ataxia (where you may become shaky and unsteady and have slurred speech)
  • have (or have had) problems with alcohol or drugs
  • have recently had a loss or bereavement, depression or thoughts of harming yourself or suicide
  • have been diagnosed with a personality disorder
  • are trying to get pregnant, are already pregnant or breastfeeding
  • are going to have a general anaesthetic for an operation or dental treatment

4. How and when to take it

It's important to take clonazepam exactly as your doctor tells you to.

You'll usually start on a low dose and gradually increase it over 2 to 4 weeks until your doctor thinks the dose is the right dose.

Your doctor will tell you if you need to take clonazepam in 1 dose or split your dose so you take it up to 3 times each day. Ask a doctor or pharmacist if you're not sure how to take it.

The usual dose for:

  • epilepsy in adults – the starting dose is 1mg taken at night (increasing to 4mg to 8mg over 2 to 4 weeks)
  • epilepsy in children – the dose varies depending on their age. It will be increased gradually over 2 to 4 weeks
  • involuntary muscle spasms (adults) – the starting dose is 1mg taken at night (increasing to 4mg to 8mg over 2 to 4 weeks)
  • panic disorder – 1mg to 2mg each day
  • restless legs syndrome – 500 micrograms to 2mg each day

If you're older than 65 or have kidney, liver or severe breathing problems, your doctor may recommend a lower dose.

Take clonazepam tablets with a drink of water. You can take the tablets or liquid with or without food.

What if I forget to take it?

If you forget to take your clonazepam, take it as soon as you remember, unless it's nearly time for your next dose.

In this case, just leave out the missed dose and take your next dose as usual.

Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.

If you forget doses often, it may help to set an alarm to remind you.

You could also ask a pharmacist for advice on other ways to remember your medicines.

What if I take too much?

The amount of clonazepam that can lead to an overdose varies from person to person.

If you take too much clonazepam, you may get symptoms including:

  • poor coordination or trouble speaking
  • feeling sleepy
  • a slow or irregular heartbeat
  • uncontrolled eye movements
  • muscle weakness
  • feeling overexcited

Urgent advice: Contact 111 for advice if:

  • you take too much clonazepam

Go to or call 111

If you need to go to A&E, do not drive yourself. Get someone else to drive you or call for an ambulance.

Take the clonazepam packet, or the leaflet inside it, plus any remaining medicine with you.

5. Side effects

Like all medicines, clonazepam can cause side effects in some people, but many people have no side effects or only minor ones.

Common side effects

These common side effects happen in more than 1 in 100 people.

If you get these side effects, keep taking the medicine and speak to a doctor if they bother you or do not go away:

  • disturbed sleep (such as vivid dreams)
  • feeling sleepy (drowsy) in the daytime
  • feeling light-headed, unsteady or dizzy
  • muscle weakness

Serious side effects

It happens rarely, but some people can have serious side effects when taking clonazepam.

Tell a doctor straightaway if:

  • your breathing becomes very slow or you have short, shallow breaths
  • your skin or the whites of your eyes turn yellow – this could be a sign of liver problems
  • you find it difficult to remember things (amnesia) or are confused
  • you see or hear things that are not there (hallucinations) or think things that aren't true (delusions)
  • problems with your coordination or controlling your movements
  • you have swollen ankles, a racing heartbeat, cough and feel tired – this could be a sign of heart problems
  • you bruise easily, feel tired, have nosebleeds and have breathlessness – this can be a sign of blood problems
  • you notice mood changes such as talking too much, feeling overexcited, restless, irritable or aggressive (mood changes can become serious and are more likely in children and people over 65 years old)

Serious allergic reaction

In rare cases, clonazepam may cause a serious allergic reaction (anaphylaxis).

Immediate action required: Call 999 or go to A&E now if:

  • you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
  • you're wheezing
  • you get tightness in the chest or throat
  • you have trouble breathing or talking
  • your mouth, face, lips, tongue or throat start swelling

You could be having a serious allergic reaction and may need immediate treatment in hospital.

These are not all the side effects of clonazepam. For a full list, see the leaflet inside your medicine packet.

You can report any suspected side effect to the .

6. How to cope with side effects

What to do about:

  • disturbed sleep (such as vivid dreams) – speak to a doctor; they may suggest a different medicine or a lower dose.
  • feeling sleepy (drowsy) in the daytime – this should get better after a week or so but speak to a doctor; they may suggest a lower dose. Do not drive, ride a bike or use machinery or tools until you feel better.
  • feeling lightheaded, unsteady or dizzy – try to lie down or sit down. Do not drive, ride a bike or use machinery or tools until you feel better. If you still have these side effects after a week or they get worse, speak to a doctor.
  • muscle weakness – try to sit down if you feel weak. If you still have these side effects after a week or so, or if they get worse, speak to a doctor.

7. Pregnancy and breastfeeding

Clonazepam is not usually recommended during pregnancy. There's not enough information to know if it's safe, and it might mean your baby is born with withdrawal side effects.

If you become pregnant while taking clonazepam, speak to a doctor. Do not stop taking clonazepam suddenly if you have been taking it regularly.

Your doctor can explain the risks and benefits of taking clonazepam and will help you choose the best treatment for you and your baby.

You may need to keep taking clonazepam during pregnancy as it's important for you to remain well.

Clonazepam and breastfeeding

Clonazepam is not recommended while breastfeeding.

If you're breastfeeding or want to breastfeed, talk to a doctor or pharmacist, as there might be better medicines for you. It will depend on what you're taking clonazepam for.

If your doctor says it's OK to take clonazepam while breastfeeding and you notice that your baby's not feeding as well as usual, seems unusually sleepy, has unusual breathing, or you have any other concerns about them, talk to your health visitor or doctor as soon as possible.

Non-urgent advice: Tell your doctor if you're:

  • trying to get pregnant
  • pregnant
  • breastfeeding

8. Cautions with other medicines

Some medicines interfere with the way clonazepam works and increase the chance of you having side effects.

Before you start taking clonazepam, tell a doctor if you're taking:

  • anticonvulsants, used to treat epilepsy
  • antipsychotics and antidepressants, used to treat mental health problems and depression
  • hypnotics, used to treat anxiety or sleep problems
  • medicines used to treat muscle spasms, such as baclofen or tizanidine
  • medicines used to lower blood pressure including ACE inhibitors such as enalapril and lisionopril; calcium channel blockers such as amlodipine and felodipine; and diuretics such as indapamide and bendroflumethiazide
  • drowsy (sedating) antihistamines, such as chlorphenamine or promethazine
  • strong painkillers such as codeine, methadone, morphine, oxycodone, pethidine or tramadol.
  • cimetidine, a medicine for stomach problems and heartburn
  • rifampicin, (to treat bacterial infections) or antifungal medicines such as fluconazole

Mixing clonazepam with herbal remedies or supplements

There's very little information about taking herbal remedies and supplements with clonazepam.

Do not take herbal medicines for anxiety or insomnia, such as valerian or passionflower, with clonazepam. They can increase the drowsy effects of clonazepam and may also have other side effects.

Important

For safety, tell a doctor or pharmacist if you're taking any other medicines, including herbal medicines, vitamins, or supplements.

9. Common questions

How does clonazepam work?

Clonazepam belongs to a group of medicines called benzodiazepines.

It works by increasing levels of a calming chemical, gamma-amino-butyric-acid (GABA), in your brain.

Depending on your health condition, this can relieve anxiety, stop seizures and fits or relax tense muscles. This can also help relieve muscle spasms or symptoms of restless legs syndrome.

How will it make me feel?

Clonazepam will help you feel calmer and it can reduce your feelings of anxiety.

It can also make you feel sleepy and relaxed and might make you feel confused when you first start taking it.

This will usually get better as you get used to taking the medicine.

It is important to not drive, ride a bike or use tools or machinery if you have any of these side effects.

How long does it take to work?

How quickly clonazepam works will depend on what condition you're taking it for.

For seizures, fits and involuntary muscle spasms, it might take a few days to a week for clonazepam to work fully. This is because your dose will be increased gradually until you're taking the right amount.

For panic disorder and restless legs syndrome, clonazepam should take around 1 hour to start working.

How long will I take it for?

How long you take it for will depend on why you're taking it.

When used for epilepsy, clonazepam is usually prescribed long term.

For other conditions, your doctor will want to regularly review if you still need clonazepam.

If you're prescribed clonazepam for more than 4 weeks, your doctor may reduce your dose gradually before stopping it, to prevent withdrawal symptoms.

Will I become addicted?

Clonazepam is not likely to be addictive if you take it for a short time (2 to 4 weeks).

If you've been taking it for longer than 2 to 4 weeks, your doctor will reduce your dose gradually if they want you to stop taking it.

You're more likely to get addicted if you have, or have previously had, problems with alcohol or drugs.

Speak to your doctor if you've had problems with alcohol or recreational drugs. They may want to try you on a different medicine.

What happens when I stop taking clonazepam?

If your doctor recommends you stop taking clonazepam and you've been taking it for more than 2 to 4 weeks, they will reduce your dose gradually.

This allows your body to get used to being without the medicine and reduces the chance of side effects when you stop taking it.

If you stop taking it suddenly, you may get some side effects, such as:

  • confusion
  • seizures or fits
  • depression
  • feeling nervous or irritable
  • sweating
  • diarrhoea

The risk of these side effects will be reduced if you lower your dose gradually.

Important

Do not stop taking clonazepam without talking to a doctor.

Can I drink alcohol with it?

Do not drink alcohol while taking clonazepam. Alcohol can increase the side effects of clonazepam.

It can make you go into a very deep sleep. There's a risk you may not be able to breath properly and you may have difficulty waking up. This can be dangerous.

Will recreational drugs affect it?

Using cannabis, heroin or methadone with clonazepam will increase the drowsy effects of clonazepam.

It can make you go into a very deep sleep. There's a risk you will not be able to breathe properly, and you may have difficulty waking up. This can be dangerous.

Using cocaine or other stimulants such as MDMA (ecstasy) and amphetamines with clonazepam can also lead to drowsiness.

Talk to a doctor if you think you might use recreational drugs while taking clonazepam.

Are there foods and drinks I need to avoid?

It's best to not have drinks such as coffee, tea and cola, or to eat a lot of chocolate because these contain caffeine. Caffeine is a stimulant and may reduce the calming effects of clonazepam.

Alcohol can increase the effects of clonazepam and make you go into a very deep sleep. It's important you do not drink alcohol while you're taking clonazepam. There's a risk you will not be able to breathe properly and you may have difficulty waking up. This can be dangerous.

Will it affect my contraception?

Clonazepam will not affect any contraception, including the combined pill and emergency contraception.

Will it affect my fertility?

There's no evidence that clonazepam will affect fertility in either men or women.

If you're trying to get pregnant, or you're having problems getting pregnant while on clonazepam, speak to a doctor.

Can I drive or ride a bike?

Do not drive a car or ride a bike if clonazepam makes you sleepy, gives you blurred vision, or makes you feel dizzy, clumsy or unable to concentrate or make decisions.

This may be more likely when you first start taking clonazepam, but could happen at any time (for example, when starting another medicine).

It's an offence to drive a car if your ability to drive safely is affected.

It's your responsibility to decide if it's safe to drive. If you're in any doubt, do not drive.

Even if your ability to drive is not affected, the police have the right to request a saliva sample to check how much clonazepam is in your body.

GOV.UK has more .

Talk to a doctor or pharmacist if you're unsure whether it's safe for you to drive while taking clonazepam.

Can lifestyle changes help with panic disorder and restless leg syndrome?

If you have panic disorder, there are some things you can try to help, including:

If you have restless legs syndrome, there are some lifestyle changes that can help, including:

  • quitting smoking
  • exercising regularly (but avoid exercising close to bedtime)
  • good sleep habits, such as going to bed and getting up at the same time every day, not napping during the day, taking time to relax before going to bed
  • avoiding medicines that trigger the symptoms or make them worse (if you think medicine is causing your symptoms, continue to take it and make an appointment to see a doctor)

Useful resources

Page last reviewed: 2 January 2020
Next review due: 2 January 2023