Benzodiazepines are a class of psychoactive drugs used to treat anxiety, insomnia, and a range of other conditions. They are one of the most widely prescribed medications in the US, particularly among elderly patients.
The first benzodiazepine - chlordiazepan - was accidentally developed in 1955 by Leo Sternbach and since then many more have been designed. Benzodiazepines possess sedative, hypnotic, anti-anxiety, anticonvulsant and muscle relaxant properties.
Short term use of these mediations are generally safe and effective. However, the long term use of benzodiazepines is very controversial, because of the potential of tolerance, dependance and other adverse effects.
In this article, we will look at how benzodiazepines work, what they are used for and any related side effects and risks.
Fast facts on benzodiazepines
Here are some key points about benzodiazepines. More detail and supporting information is in the main article.
- Benzodiazepines are commonly used to treat insomnia and anxiety
- They work by enhancing the effects of gamma-aminobutyric acid (GABA)
- The effects of benzodiazepines include hypnotic, anticonvulsant and muscle relaxant properties
- Chlordiazepan was the first benzodiazepine to be synthesized
- Recovering alcoholics use benzodiazepines to help counter withdrawal symptoms
- There are a number of benzodiazepines - examples include Lectopam, Xanax and Rohypnol
- Side effects of benzodiazepines might include dizziness, trembling and confusion
- Long-term use of benzodiazepines can result in physical dependence
- Withdrawal symptoms of benzodiazepines can include insomnia, depression and sweating
- Oral contraceptives cause benzodiazepines to accumulate and increase side effects.
Medical uses of benzodiazepines
Benzodiazepines were first discovered in 1955.
- Generalized anxiety disorder (GAD) - benzodiazepines are often used in the treatment of GAD. The National Institute of Health and Clinical Excellence (NICE) recommends the use of benzodiazepines for short term GAD treatment for no longer than one month. SSRIs are considered to be more effective at treating long-term GAD.
- Insomnia - as Benzodiazepines can lead to dependence, they are normally only used as a short-term treatment for severe insomnia or on a "irregular/as-needed" basis.
- Seizures - benzodiazepines are powerful anticonvulsants and are very effective at preventing prolonged convulsive epileptic seizures. The first-line hospital choices for treating seizures are either clonazepam, diazepam, or lorazepam.
- Alcohol withdrawal - the most common benzodiazepine prescribed for alcohol withdrawal is chlodiazepoxide, followed by diazepam. The drugs help alcoholics with detoxification and reduce their risk of severe alcohol withdrawal effects. A study conducted at the University of Ioannina School of Medicine in Greece found that people given benzodiazepines were 84% less likely to havealcohol withdrawal-related seizures compared to those given placebos.
- Panic attacks - because of their rapid anti-anxiety effects, benzodiazepines are very effective at treating anxiety associated with panic disorder. The American Psychiatric Association says that their use for initial treatment is strongly supported by many different study trials. However, UK based NICE says that long-term use of benzodiazepines for the treatment of panic disorder is not recommended.
Mechanism of benzodiazepines
The human brain contains many different neurotransmitters which are responsible for sending messages between brain cells, these messages have either "tranquilizing" or "excitatory" effects.
When someone feels overly anxious the brain becomes "excited" and over-active, tranquilizing transmitters need to quickly send messages to brain cells to slow down activity in the brain and reduce the symptoms of anxiety.
GABA is the brain's tranquilizing neurotransmitter, and billions of brain cells respond to its signals.
Benzodiazepines work by enhancing the effect of the neurotransmitter GABA. The drugs contain chemicals which add to the calming effect already produced by the human body and essentially keep the brain in a more "tranquilized" state.
Different types of benzodiazepines
There are many different benzodiazepines and they all have differences in potency, speed at which they are metabolized, and "half-life" (time required for the quantity of the drug in the bloodstream to decrease to half its value), and therapeutic use.List of benzodiazepines:
- Alprazolam (Xanax) - FDA approved for the treatment of panic and anxiety disorders. Alprazolam is the most prescribed benzodiazepine in the US
- Bromazepam (Lectopam) - used as a short-term treatment for anxiety and to alleviate anxiety before surgery
- Brotizolam (Lendormin) - a very potent anxiolytic, hypnotic, and anticonvulsant drug with fast onset of action. It is used to treat severe insomnia. The drug is not approved in Canada, Britain and the US
- Chlordiazepoxide (Librium) - used for the management of alcohol withdrawal syndrome
- Clonazepam (Klonopin) - a high potency sedative, anxiolytic, hypnotic, and anti-convulsant drug. Clonazepam is a long acting benzodiazepine with a half life between 20 to 50 hours. The FDA has approved the drug for treatment of epilepsy and panic disorder
- Clorazepate (Tranxene) - a hypnotic, sedative, anxiolytic drug used to treat severe insomnia and anxiety disorders
- Clotiazepam (Clozan) - used for short term anxiety treatment
- Cloxazolam (Sepazon) - prescribed to treat anxiety
- Diazepam (Valium) - an anxiolytic, hypnotic, sedative and anticonvulsant drug with rapid onset. It is used to treat panic attacks, insomnia, seizures, restless leg syndrome, and alcohol withdrawal. Diazepam is also used for the treatment of benzodiazepine dependence because of its low potency
- Estazolam (ProSom) - a sedative, anxiolytic drug prescribed for short term treatment of insomnia
- Etizolam (Etilaam) - used to treat insomnia
- Flunitrazepam (Rohypnol) - usually prescribed for short term treatment of chronically severe insomnia. The drug is sometimes misused as a date rape drug because of its ability to cause amnesia
- Flurazepam (Dalmane) - a sedative, anxiolytic drug used to treat mild to moderate insomnia
- Loprazolam (Somnovit) - a sedative, anxiolytic drug used to teat moderately severe insomnia
- Lorazepam (Ativan) - a very high-potent drug with sedative, anxiolytic, and muscle relaxation properties. It is prescribed for the short-term management of severe anxiety
- Midazolam (Dormicum) - a high potent drug with anxiolytic, amnestic, hypnotic, anticonvulsant, skeletal muscle relaxant, and sedative properties. It is used to treat acute seizures and severe insomnia, as well as inducing sedation before surgical procedures
- Nitrazepam (Alodorm) - a hypnotic drug used to treat severe insomnia
- Nordazepam (Nordaz) - an anticonvulsant, anxiolytic, muscle relaxant and sedative drug used to treat anxiety
- Oxazepam (Seresta) - used to treat anxiety and insomnia and control the symptoms of alcohol withdrawal
- Temazepam (Restoril) - approved for the short-term treatment of insomnia
- Triazolam (Apo-Triazo, Halcion, Hypam, and Trilam) - only used as a sedative to treat severe insomnia.
On the next page, we look at the side effects, risks, interactions and misuse of benzodiazepines.