Benzos Decoded

How do benzodiazepines work?

Benzodiazepines are used to treat anxiety and sleeping problems. (They are also important for treating epilepsy, for sedation in minor surgery, and before general anaesthetics, but this is not covered here.)

Although these drugs are often called 'minor' tranquillisers, the term is misleading because they differ markedly and in many ways from the so-called 'major' tranquillisers (antipsychotic drugs), and their use is by no means minor.

Benzodiazepines work by quietening the activity of the brain. They act on all areas of the brain, including those responsible for rational thought, for memory, for the emotions, and essential functions, such as breathing. They are very effective for treating anxiety, as well as acting as sedatives, as sleeping pills, and to reduce the memory of unpleasant events, such as operations. But their widespread action is also responsible for their many unwelcome effects. They may also cease to be effective after about four months.

Dependence and withdrawal
The first benzodiazepine was chlordiazepoxide (trade name Librium), which came into use in 1960. The best known is diazepam, or Valium, which followed in 1962. Reports of people becoming dependent on benzodiazepines began to emerge as early as 1961, connected mostly to their use in treating anxiety or insomnia. It was not until 1980 that the Committee on the Review of Medicines expressed concern, although they believed the risk of dependence was low.

In the 1980s, it was generally recognised that dependence and withdrawal were serious problems with these drugs, and their use should be limited. By the end of the decade, it was estimated that half a million people were addicted to benzodiazepines, and in the 21st century the problem still affects a large number of people, many of whom have been taking these drugs for 20 or 30 years.

However, benzodiazepines are still the drugs most commonly prescribed for anxiety and as sleeping pills, and in 2001 the number of prescriptions written was 12,648,900. Many people are prescribed them while they are in psychiatric wards, and are discharged from hospital still taking them.

When should benzodiazepines be prescribed?

Because of the problems of becoming dependent on these drugs, and finding it difficult to withdraw from them, benzodiazepines should be used only for the short-term treatment of severe anxiety or severe insomnia. They are not for long-term use.

According to the British National Formulary (BNF):

• Benzodiazepines are indicated for the short-term relief (two to four weeks only) of anxiety that is severe, disabling or subjecting the individual to unacceptable distress, occurring alone or in association with insomnia or short-term psychosomatic, organic or psychotic illness.
• The use of benzodiazepines to treat short-term 'mild' anxiety is inappropriate and unsuitable.
• Benzodiazepines should be used to treat insomnia only when it is severe, disabling, or extremely distressing.

A report by the Royal College of Psychiatrists suggests that the drugs should not be prescribed regularly for longer than one month and, ideally, should be taken only as required and with a gap every few days. Treatment should always be at the lowest possible dose, for the shortest possible time.

Although benzodiazepines are effective in treating anxiety states, it's clear that there are situations when their use is not justified. In bereavement, for example, tranquillisers may stop people from grieving properly. Children should only take benzodiazepines for acute anxiety or insomnia caused by fear.

Benzodiazepines are often used together with antipsychotic drugs to treat schizophrenia, or similar conditions. They may be prescribed, short-term, to help with over-excitement, agitation and severe psychotic disturbance, to aid rapid tranquillisation. It's better than giving a high dose of antipsychotic drugs, which have a risk of severe side effects.

Benzodiazepines used for anxiety
Long-acting
Chlordiazepoxide (Librium, Tropium)
Normal dose: 10mg three times per day, increased, if necessary, to a maximum of 100mg per day
Half-life: 5–30 hours (36–200 hours*)
*This refers throughout to the half-life of the active metabolite, the substance the drug turns into, in the body, which has the therapeutic effect.

Clorazepate (Tranxene)
Normal dose: 7.5–22.5mg per day
Half-life: (36–200 hours*)

Diazepam (Valium, Tensium, Dialar, Diazemuls, Stesolid, Valclair)
Normal dose: 6mg per day, increased up to 30mg per day. For children (for night terrors and sleep-walking) the dose is 1–5mg. Available in tablet form in doses of 2mg, 5mg and 10mg. Doses vary, according to the condition
Half-life: 20–100 hours (36–200 hours*)

Benzodiazepines used for anxiety
Short-acting
Alprazolam (Xanax)
Normal dose: 0.25–0.5mg three times per day, up to a maximum of 3mg per day
Half-life: 6–12 hours

Lorazepam (Ativan)
Normal dose: 1–4mg per day
Half-life: 10–20 hours

Oxazepam
Normal dose: 15–30mg, three to four times per day. Maximum dose 50mg
Half-life: 4–15 hours

Benzodiazepines used as sleeping pills
Long-acting
Flunitrazepam (Rohypnol)
Normal dose: 0.5–1mg at bedtime, up to a maximum of 2mg
Half-life: 18–26 hours (36–200 hours*)

Flurazepam (Dalmane)
Normal dose: 15–30mg at bedtime
Half-life: (40–250 hours*)

Nitrazepam (Mogadon, Remnos, Somnite)
Normal dose: 5–10mg at bedtime
Half-life: 15–38 hours

Benzodiazepines used as sleeping pills
Short-acting
Loprazolam (Dormonoct)
Normal dose: 1mg at bedtime, can increase to 1.5 or 2mg
Half-life: 6–12 hours

Lormetazepam
Normal dose: 0.5–1.5mg at bedtime
Half-life: 10–12 hours

Oxazepam
Normal dose: 15–25mg at night. Maximum dose 50mg
Half-life: 4–15 hours

Temazepam
Normal dose: 10–20mg at bedtime. Exceptionally, 30–40mg
Half-life: 8–22 hours