Benzodiazepines

Benzodiazepines are widely used as anxiolytics and hypnotics. Some are employed for muscle relaxant and anticonvulsant properties - note especially intravenous diazepam in the treatment of status epilepticus.

Benzodiazepines are a group of drugs which potentiates the activity of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) (1). It exerts its effect as hypnotics, anxiolytics, anticonvulsants, and muscle relaxants (1).

According to the British National Formulary (BNF), benzodiazepines can be grouped into:

• hypnotics - used for the short-term treatment of insomnia, e.g. - nitrazepam, flunitrazepam, flurazepam, loprazolam, lormetazepam and temazepam
• anxiolytics - e.g. - diazepam, oxazepam, lorazepam, alprazolam and chlordiazepoxide

In 1988, the Committee on Safety in Medicines (CSM) published guidelines on appropriate use of benzodiazepines. It recommends that the use of benzodiazepines should be limited in the following ways:

• use
  • as anxiolytics
    • 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
  • as hypnotics
    • benzodiazepines should be used to treat insomnia only when it is severe, disabling, or subjecting the individual to extreme distress (2).
• dose
  • the lowest dose which can control the symptoms should be used. It should not be continued beyond four weeks.
  • long-term chronic use is not recommended
  • treatment should always be tapered off gradually
  • patients on benzodiazepines for a long time may require a longer period during which doses are reduced.
  • when a benzodiazepine is used as a hypnotic, treatment should, if possible, be intermittent.

Note that alcohol potentiates their effects, and there are problems with the increase in aggression in some patients.

Reference:

• (1) National Addiction Centre, King's College London and School of Social and Community Medicine 2011. The changing use of prescribed benzodiazepines and z-drugs and of over-the-counter codeine-containing products in England: a structured review of published English and international evidence and available data to inform consideration of the extent of dependence and harm.
• (2) Medicines and Healthcare products Regulatory Agency (MHRA) 1988. Current Problems in Pharmacovigilance. 21:1-4