The benzodiazepines are a class of drugs with hypnotic, anxiolytic, anticonvulsant, amnestic and muscle relaxant properties.
Benzodiazepines are often used for short-term relief of severe, disabling anxiety or insomnia. Long-term use can be problematic due to the development of tolerance and dependency. They are believed to act on the GABA receptor GABAA, the activation of which dampens higher neuronal activity. They began to be widely prescribed for stress-related ailments in the 1960s and 1970s.
Benzodiazepines are commonly divided into three groups. Short-acting compounds act for less than six hours and have few residual effects if taken before bedtime, but rebound insomnia may occur and they might cause wake-time anxiety. Intermediate-acting compounds have an effect for 6-10 hours, may have mild residual effects but rebound insomnia is not common. Long-acting compounds have strong sedative effects that persist. Accumulation may occur.
The various benzodiazepines are listed in order of the shortest acting to the longest acting (by the approximate elimination half-life of the drug), however this time may greatly vary between persons.
Benzodiazepines are used in many situations, depending on their pharmacokinetics. The main use of the short-acting benzodiazepines is in insomnia, while anxiety responds better to medium- to long-acting substances that will be required all day.
Midazolam is mostly used as an injection for sedation before surgical procedures.
Abuse and dependence,br>
Benzodiazepines induce physical dependence and are potentially addictive. An abrupt discontinuation of benzodiazepine input may result in convulsions, confusion, psychosis, or effects similar to delirium tremens.
Every person on long-term or high dosage of any benzodiazepine should be carefully weaned off the drug. Onset of the withdrawal syndrome might be delayed, and it might be delayed longer than the barbiturate withdrawal syndrome. Even when withdrawal from short-acting types often presents early.
The benzodiazepine withdrawal syndrome is characterized by:
• loss of appetite
Some of the withdrawal symptoms are identical to the symptoms for which the medication was originally prescribed. They are valued by many patients for their ability to ameliorate existing conditions, whlie benzodiazepine dependency can cause them.
Benzodiazepine intoxication may lead to coma, but does not cause severe biochemical disturbances and therefore carries a relatively good prognosis. The antidote for all benzodiazepines is flumazenil (Annexate®), which is occasionally used empirically in patients presenting with unexplained loss of conciousness in emergency room setting.
2005 Morpheus Institute. All rights reserved.