Benzodiazepines and Z Drugs

What are benzodiazepines and Z drugs?


Benzodiazepines are a group of medicines that are sometimes used to treat anxiety, sleeping problems and other disorders. Examples include: diazepam, lorazepam (trade name AtivanĀ®), chlordiazepoxide, oxazepam, temazepam, nitrazepam, flurazepam, loprazolam, lormetazepam, clobazam and clonazepam.

Benzodiazepines work by affecting the way certain brain chemicals (neurotransmitters) transmit messages to certain brain cells. In effect, they decrease the excitability of many brain cells. This has a calming effect on various functions of the brain.

Z drugs

Medicines called zaleplon, zolpidem and zopiclone are commonly called the Z drugs. Strictly speaking, Z drugs are not benzodiazepines but are another class of medicine. However, they act in a similar way to benzodiazepines. (They have a similar effect on the brain cells as benzodiazepines.) Z drugs have similar long-term usage problems as benzodiazepines.

What are benzodiazepines and Z drugs used for?

Benzodiazepines for anxiety

Symptoms of anxiety include: agitation, tension, irritability, palpitations, shakiness, sweating, excess worry, sleeping badly, poor concentration, fast breathing and sometimes a knotted feeling in the stomach and other muscles. There are various causes of anxiety. Sometimes it is a sudden life crisis such as a bereavement or redundancy. Some people have an anxious personality and feel anxious fairly often. Although most people will feel anxious at some time, sometimes the symptoms become prolonged and distressing. (See separate leaflets called ‘Anxiety Disorders’ and ‘Anxiety – Generalised Anxiety Disorder’, ‘Anxiety – Self Help Guides’ and ‘Relaxation Exercises’ for details.)

Treatments for anxiety include: learning to relax, anxiety management courses, cognitive therapy and behavioural therapy. Simply talking things over with a friend, counsellor, or with members of a self-help group may also help. However, if symptoms become severe, you may be advised to take a benzodiazepine medicine for a short time.

Benzodiazepines and Z drugs as sleeping tablets

A short course of a benzodiazepine or a Z drug may be prescribed if a medicine is felt necessary to help with sleeping difficulty (insomnia). A separate leaflet called ‘Insomnia – Sleeping Tablets’ gives more details. However, there are other ways of helping to get a good night’s sleep. These are described in another leaflet called ‘Insomnia (Poor Sleep)’.

Other uses of benzodiazepines

A dose of a benzodiazepine is often given as a pre-med to reduce anxiety before an operation. A large dose is commonly given as a sedative during medical procedures that may cause anxiety or discomfort. The medicine not only reduces anxiety but also has an amnestic effect. This means that you do not remember much about the procedure. Some benzodiazepines are occasionally used to treat muscle spasm and certain types of epilepsy as they can prevent seizures.

How effective are benzodiazepines and Z drugs?

If you are not used to taking benzodiazepines or Z drugs, the first doses are usually good at easing symptoms of anxiety or promoting sleep. A benzodiazepine does nothing to remove any underlying cause of anxiety such as a life crisis. However, if your symptoms are eased, you may be able to cope better with any problems.

Benzodiazepines and Z drugs work best in situations where anxiety or sleeping difficulty is expected to last only a short while. They are not so useful if you have an ongoing anxious personality or long-term sleeping difficulty. However, a short course may help you over a particularly bad spell.

You can usually stop a benzodiazepine or Z drug without any problems if you take it for just a short period of time (no more than 2-4 weeks).

Why should benzodiazepine and Z drugs be used only for a short time?

When benzodiazepines were first used they were thought to be safe. The problems with their long-term use were not known. In 1981, benzodiazepines were the most commonly prescribed medicines in western countries. It was because benzodiazepines worked so well to ease symptoms of anxiety and poor sleep that many people came back for more. Some people started to take them regularly.

However, it is now known that if you take a benzodiazepine or Z drug for more than 2-4 weeks, you may develop problems (see below). Therefore, most doctors will now only prescribe benzodiazepines and Z drugs for a short period.

What happens if you use a benzodiazepine or Z drug for longer?


If you take a benzodiazepine or Z drug regularly, the helpful effect on easing anxiety or in helping sleep usually lasts for a few weeks. However, after a few weeks, the body and brain often become used to the benzodiazepine or Z drug. The medicine then gradually loses its effect. The initial dose then has little effect. You then need a higher dose for it to work. In time, the higher dose does not work and you need an even higher dose and so on. This effect is called tolerance.

Dependence (addiction)

There is a good chance that you will become dependent on a benzodiazepine or Z drug if you take it for more than four weeks. This means that withdrawal symptoms occur if the tablets are stopped suddenly. In effect, you need the medicine to feel normal. Possible withdrawal symptoms include:

  • Psychological symptoms – such as anxiety, panic attacks, odd sensations, feeling as if you are outside your body, feelings of unreality, or just feeling awful. Rarely, a serious mental breakdown can occur.
  • Physical symptoms such as sweating, being unable to sleep, headache, tremor, feeling sick, palpitations, muscle spasms and being oversensitive to light, sound and touch. Rarely, convulsions occur.
  • In some cases the withdrawal symptoms seem like the original anxiety symptoms.

The duration of withdrawal symptoms varies but often lasts up to six weeks and sometimes longer. Withdrawal symptoms may not start for two days after stopping the tablet and tend to be worst in the first week or so. Some people have minor residual withdrawal symptoms for several months.

Therefore, you may end up taking the medicine to prevent withdrawal symptoms but, because of tolerance, the medicine is no longer helping the original anxiety or sleeping problem. But note: you are unlikely to become dependent on a benzodiazepine or Z drug if you take it for a short period only.

Some other possible problems with benzodiazepines and Z drugs

Even if you take a benzodiazepine or Z drug for a short time, you may feel drowsy during the daytime. Some people, especially older people, are at greater risk of having a fall and injury because of the drowsiness. If you drive, you may be more likely to be involved in a car crash. Some people have described themselves as being in a zombie state when they were taking a benzodiazepine on a long-term basis.

For a full list of possible side-effects whilst taking any tablet, read the leaflet that comes with the packet of tablets.

What if I have been taking a benzodiazepine or Z drug for a long time?

If you have been taking a benzodiazepine or Z drug for over four weeks and want to come off it, it is best to discuss the problem with a doctor. Some people can stop taking benzodiazepines or Z drugs with little difficulty. However, many people develop withdrawal symptoms if they suddenly stop taking a benzodiazepine or Z drug. To keep withdrawal effects to a minimum, it is often best to reduce the dose of the medicine gradually over a number of weeks or months before finally stopping it. Your doctor will advise on dosages, time scale, etc.

There is also another leaflet called ‘Benzodiazepines and Z Drugs – Stopping After Long-term Use’ which gives details.

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