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Benzodiazepines

Benzodiazepines are a class of medications that temporarily reduce anxiety, restlessness and agitation, and help to induce sleep. They all work by enhancing the activity of GABA in the central nervous system, which is a neurotransmitter that serves to calm or reduce the activity of many brain centers. In general medicine these medications are also used to control seizures, relax muscles, and to sedate patients during surgical procedures.

Benzodiazepines only produce their effects for the few hours that they remain in a person's blood circulation. In cases where the anxiety, restless, agitation or insomnia are ongoing, these medications will need to be used regularly if they are to control the symptoms.

However, the main problem with using benzodiazepines on a regular basis is that this can lead to tolerance, dependence and abuse. With consistent use of these medications, the body adapts by reducing the number of GABA receptors in the central nervous system. This means that a given dose of the medication can become less and less effective over time, that larger doses are needed to achieve the same effect, and that if one suddenly stops using a benzodiazepine after long-term use one can experience severe withdrawal symptoms that include intense anxiety, agitation, insomnia, and in some cases even seizures and delirium.

That being said, in many cases benzodiazepines are used regularly and the majority of individuals receiving this kind of treatment do not develop abuse or dependence [ref]. Regular benzodiazepine use is indicated for Panic Disorder, Social Phobia, and Generalized Anxiety Disorder, and is often used for other Anxiety Disorders as well as for other psychiatric conditions where anxiety, restlessness, agitation or insomnia are important symptoms.

There are many different benzodiazepines available on the market. They differ mainly in the duration of their effects and in how they are metabolized by the body. Please refer to the Benzodiazepine Equivalency Table below for further information.

As a general rule, it is best to avoid benzodiazepines that give their effect over a short duration, that is less than 3 hours, as is the case with Alprazolam immediate-release, for this can cause significant rebound symptoms of anxiety when the effects wear off and can lead to dependence. Instead, it is generally recommended to use benzodiazepines with longer durations of action, such as Clonazepam or Diazepam.

In the elderly, or for individuals with liver impairment, it is preferable to use benzodiazepines with shorter half-lives and fewer active metabolites, such as Oxazepam or Lorazepam, so that the medication does not accumulate in the person's blood circulation and reach high levels. In the elderly, benzodiazepines can contribute to memory and concentration difficulties, confusion, and can also increase the risk of falls.

Benzodiazepine Equivalency Table
Generic name
Brand names
Dose equivalency 1

Half-life 2
Time to peak 3
Duration of clinical effects 4
Alprazolam Xanax, Xanor, Tafil 0.5 6-20 1-2 1-3
Bromazepam Lexotan, Lexomil 3 8-30 0.5-4  
Chlordiazepoxide Librium 20 24-100 1-4 6-12
Clobazam Frisium 15 12-60    
Clonazepam Klonopin, Rivotril 0.5 18-60 1-4 4-8
Clorazepate Tranxene 7.5 36-100    
Diazepam Valium 5 30-100 1-2 6-12
Estazolam ProSom, Nuctalon 1 8-24 0.5-6  
Flunitrazepam Rohypnol 0.5 24-100    
Flurazepam Dalmane 15 40-250 0.5-1  
Halazepam Paxipam 20 30-100 1-3  
Ketazolam Anxon 10 30-200 3.2  
Loprazolam Dormonoct 1 6-12    
Lorazepam Ativan, Temesta, Tavor 1 8-24 2-4 4-6
Lormetazepam Noctamid 1 10-12    
Medazepam Nobrium 5 36-200    
Midazolam Dormicum, Versed 1.5 <6    
Nitrazepam Mogadon 5 15-48 0.5-7  
Nordazepam Nordaz, Calmday 5 36-200    
Oxazepam Serax, Serenid,
Serepax, Seresta
15 6-12 2-3 4-6
Prazepam Centrax, Lysanxia 10 30-100 2.5-6  
Quazepam Doral 10 25-100 1.5  
Temazepam Restoril, Normison,
Euhypnos
10 3-25 1.5  
Triazolam Halcion 0.25 1.5-5.5 2  

1 These dose equivalency values are only approximate, as there can be significant variability among individuals. The true value for any individual can range from half to double of what is listed here.

2 Half-life values represent the number of hours it takes for the body to eliminate half of the medications, including its active metabolites, from the blood circulation. These values do not correspond to the actual clinical effects of these medications, which tend to be much shorter than the half-life duration (see the Duration of Clinical Effects column of the table).

3 Time to peak plasma levels represent the number of hours it takes for the medications to reach maximum concentrations in the blood circulation. Regardless of these values, most benzodiazepines begin to produce their clinical effects within 30min of being ingested.

4 The duration of clinic effects listed here refer to the number of hours that the effects of the medication continue to be felt. These values are only approximate.