Diazepam

How it works

What does diazepam do?

Diazepam improves the effect of a chemical in the brain called gamma-aminobutyric acid (GABA). GABA is a chemical whose transmission across nerves in the brain is known to produce a ‘calming effect’. When diazepam locks on to the GABA receptors in the brain, it changes shape - the GABA binds to it better and the calming effect of GABA is increased.

Diazepam is a 'controlled drug'. This means that a prescription for diazepam must be dispensed within 28 days (you can keep most other prescriptions for six months). This is because diazepam can be abused and might be sold as a street drug. If you must take it to school, it might have to be locked in a safe place.

How long does diazepam take to work?

Diazepam starts to work very quickly in your body, and you should get calming effects within two hours of taking it.

How long will I need to take diazepam?

People are not normally prescribed diazepam for more than four weeks as people can become dependent on it if they take it for longer. They may also get withdrawal symptoms when they stop taking it.

You and your doctor should talk about how long you might need to take diazepam.

If you take diazepam for anxiety or sleep problems you will probably take it for two to four weeks, to get you into a new routine.

Your doctor needs to know if...

You need to talk to your doctor or pharmacist before starting treatment with diazepam if any of the following apply to you:

• you’re allergic (hypersensitive) to diazepam or other benzodiazepine medicines, or to any of the other ingredients in your tablets
• you’re breathless or have difficulty breathing
• you have depression (with or without anxiety) or hyperactivity
• you have a phobia (a fear of an object or situation) or other mental illness
• you have myasthenia gravis
• you suffer from sleep apnoea (a condition where you stop breathing while asleep)
• you have severe liver disorder
• you have porphyria (an inherited condition causing skin blisters, gut pain and brain or nervous system disorders)
• you are planning a pregnancy or are pregnant
• you have a history of being dependent on drugs or alcohol
• you have problems with your heart and lungs or have severe kidney failure
• someone close to you has recently died
• you have low blood levels of a protein called albumin
• you have a personality disorder

Taking diazepam

You should only take diazepam as agreed with your doctor

You will get the best effect from diazepam if you take it regularly at the dose prescribed by your doctor. If this is not written on the label of your bottle or packet, please check with whoever prescribed the medication or ask your pharmacist for advice.

Some people are prescribed diazepam to be taken a few times a day. If this is the case, choose times you can always remember to take the medication, such as mealtimes or when you brush your teeth.

Some people may only have to take diazepam for one day, for instance before they have an operation.  

You should not normally be prescribed diazepam for more than four weeks.

If you are taking diazepam to help you sleep, you should take it just before bedtime.

Diazepam can be taken before or after food. Swallow tablets whole with a drink of water – if chewed, they taste bitter.

What if I miss a dose?

If you remember later during the day, take it as soon as possible.

If you forget to take it and you are coming up to the time of your next dose (if it is four hours away or less), just take the next dose.

If you take it for sleeping, you must allow yourself seven to eight hours’ sleep after taking it. So, for example, do not take it if you have only got five hours left to sleep.

Do not take a double dose.

What will happen if I forget to take my diazepam?

If you forget to take your medicine for a few days, you may start to get some uncomfortable withdrawal effects, and you could get your old symptoms back.

Stopping the use of diazepam

Stopping diazepam quickly may cause withdrawal symptoms. If you have been taking a high dose, you may feel confused or behave strangely for a short time.

Do not stop taking diazepam all at once. This could lead to unpleasant withdrawal symptoms, including:

• depression, nervousness, or irritability
• sweating
• quick or uneven heartbeat
• muscle spasms or shaking
• loss of appetite, feeling or being sick, stomach cramps or diarrhoea
• having seizures (fits)

Your doctor will help you to reduce diazepam slowly over a few days at the end of a short course of treatment. Otherwise the symptoms you are being treated for may return more intensely than before (rebound insomnia and anxiety).

The information on this page was reviewed by the College of Mental Health Pharmacy in March 2020.

Safety headlines

If you have taken more diazepam than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately – even if you do not feel any different.

Diazepam can make some people think about hurting themselves or taking their own lives. You must go straight to hospital with your tablets if you have any of these thoughts. Take your medication and a friend or family member with you to help keep you safe on the way.

When to go to the hospital

If you have taken more diazepam than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately – even if you do not feel any different.

Take a friend or family member with you in case you start to feel ill on the way. You may feel tired, confused or clumsy; get strange movements of your eyes; or have problems with your balance, coordination or speech. Your breathing could also become very slow or you could fall into a coma.

If you have taken diazepam with street drugs or alcohol, you could get very serious side effects. Go to hospital immediately and tell doctors everything you have taken so they can help you.

Diazepam can make some people think about hurting themselves or taking their own lives. You must go straight to hospital with your tablets if you have any of these thoughts.

Diazepam can cause serious side effects: allergic reactions (difficulty breathing, swelling of your face or throat, itching skin lumps), and other serious symptoms that you can find listed here. Go to a hospital if you get any of these symptoms, taking your medication with you.

Go to a doctor or hospital straight away if you get any of the following symptoms, as they might be part of an allergic reaction:

• itchy skin or rash
• swelling of the face, lips, tongue or throat
• difficulty breathing or swallowing

Side effects

Like all medications, diazepam can cause some side effects, and in some cases they can be serious.

Most side effects, however, are mild and should get better within a few days.

If they do not, you should go back to your doctor.

Do not stop taking the tablets until you talk to your doctor, or you may get withdrawal symptoms.

Body

Diazepam does not usually affect your weight.

Sleep

Diazepam may make you feel very sleepy, and this can carry on into the next day.

Some people find it more difficult to get to sleep when taking diazepam or may experience nightmares or strange dreams when taking it.

If your sleep is negatively affected by diazepam, you should discuss this with your doctor.

Sex and fertility

Sex

Diazepam can have side effects that might affect your sex life. These include:

• losing interest in sex
• feeling ‘numb’ to your normal emotions

The good effects of diazepam may have a good effect on your sex life as your symptoms settle, you sleep better, and you can concentrate on your relationships.

If these symptoms don’t pass within a couple of weeks, and this is a problem for you, go back to the doctor and see what else you could try.

Fertility

There is no evidence to suggest that diazepam affects fertility.

Pregnancy, post-natal and breastfeeding

Pregnancy

If you are pregnant or trying for a baby, you should let your doctor know this before taking diazepam.

It’s not known whether diazepam affects the developing baby and causes any abnormalities, although the risk is thought to be low.

Babies often do better when their mums are mentally well, so if diazepam has beneficial effects on your mental health, it may be best to continue taking it throughout pregnancy. Your doctor can help you weigh up the pros and cons.

Post-natal

Taking diazepam during the last few months of pregnancy can cause withdrawal symptoms in a newborn baby that include weakness and breathing difficulties. Your baby may be less active than other babies, have a low body temperature, be floppy, or have breathing or feeding difficulties for a while. Your baby’s response to the cold might also be affected for a while. 

Breastfeeding

Diazepam is passed to the baby in breast milk. This may help counter any withdrawal effects but may also make the baby too sleepy and unable to feed.

If you decide to take diazepam throughout your pregnancy, talk to your midwife or doctor.

Driving and transport

Diazepam can make you feel sleepy, dizzy and forgetful when you first start taking it. You might also find it difficult to concentrate during the first few days of treatment and may experience blurred vision and muscle weakness. For these reasons, you should not ride a bike or drive a car until you know how you will be affected.

You should also be very careful when doing anything else that requires concentration, such as operating machinery or exercising.

The effects of diazepam can last a while after taking it, so even if you only take one dose, you may feel them the next day. It’s important not to drive, ride a bike or operate machinery if you feel that your ability to concentrate has been compromised by taking diazepam.

Diazepam is in a group of medicines listed in new laws in the Road Traffic Act 1988. It is an offence to drive while under the influence of this medicine but you are NOT committing a crime if the medicine has been prescribed to you by a doctor, you are sticking to the prescribed dose and it is not affecting your ability to drive safely. The Department of Transport website has more details.

School and exams

Try not to take diazepam for the first time just before your exams.

Diazepam can affect your memory and make it harder to learn.

You may feel forgetful, very sleepy, and find it difficult to concentrate when you start taking diazepam.

You should talk to your doctor about any future exams if you are starting diazepam. You might decide together to delay starting it until you have done them. 

If they are more than a few weeks away, however, you might find that it is better to start diazepam to improve your sleep.

Do not use caffeine drinks to stay awake for exam revision – they won’t stop the diazepam blunting your learning.

Friends and family

You may want to let your family and friends know you are taking diazepam so they can support you and help you look out for side effects.

For guidance on this, check out our page on getting support with your medication.

Sport

Diazepam is not a banned substance in sport.

However, diazepam has many side effects that might make you less able to take part in sports that need a lot of focus. These include feeling sleepy, blurred eyesight, being forgetful, muscle weakness and finding it difficult to concentrate.

The good effects of diazepam may enhance your sporting performance as your symptoms settle, and you sleep better.

Alcohol, street drugs and smoking

Alcohol

Be very careful drinking alcohol while taking diazepam.

You can drink a small amount of alcohol while taking diazepam but having the two together is likely to make you very sleepy. This will be most noticeable during the early part of your treatment.

Taking large amounts of alcohol and diazepam together could affect your breathing, especially if you have an existing lung problem.

If you need to drive a car or ride a bike, or use machines at work, taking alcohol and diazepam together could be dangerous to yourself and other people.

Street drugs

Diazepam does not mix well with street drugs.

It is very easy, and serious, to overdose with any combination of diazepam and drugs.

Using cannabis with diazepam will make its sedative effect worse. You could go into a very deep sleep where you do not breathe properly and have difficulty waking up.

Cannabis and other drugs may have their own side effects on your mental health, like anxiety or psychosis. For more information, have a look at our drugs and alcohol page.

Using heroin or methadone with diazepam will also increase their combined sedative effects. You could go into a very deep sleep where you do not breathe properly and have difficulty waking up.

Using cocaine or other stimulants (like ecstasy, amfetamines, MDA, 6-APB etc.) with diazepam is likely to lead to a reduced stimulant effect. This could lead you to increase the dose of the stimulant to make up for it, which could be very dangerous.

Smoking

If you start or stop smoking while you are taking diazepam, you may have to change your dose. This is because cigarette smoke affects the amount of diazepam in your body.

If you already smoke when you begin taking this medication, you will probably need a higher dose than somebody who does not smoke. You should tell your doctor if you smoke and how much, so that they can prescribe the correct dose for you.

If you stop smoking, the level of diazepam in the body could rise, and you might need to reduce your dose of diazepam slowly over one week.

If you (re)start smoking, you might need to increase it again.

Go to your doctor for advice if you stop or start smoking.

Prescription medicines

Diazepam may affect the way other drugs work. Tell your doctor or pharmacist if you are taking any other medicines. If you are taking any other medicines, some dose adjustments may be required to ensure you get the best from the diazepam with as few side effects as possible

Tell the pharmacist you are taking diazepam if you buy medicines over the counter for common complaints, including tablets and topical medicines (things you put on your skin).

Other interactions

Watch your caffeine intake while you are taking diazepam as caffeine has the opposite effect of diazepam in your body and interferes with it working.

Do not drink large amounts of caffeine drinks (like coffee, cola or energy drinks) while you are taking diazepam.

Caffeine can cause anxiety and sleep loss – stopping these drinks might help to improve your symptoms.

References and further reading

For more helpful links and information, have a look at our references and further reading page.