Know About Benzodiazepines and How Do They Work?

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What are benzodiazepines?

Benzos or Benzodiazepines are a group of psychoactive drugs used for treating anxiety and depression. Psychoactive drugs are chemical substances that alter a person’s mood, focus, behavior, and other cognitive qualities by working on the central nervous system. Benzodiazepines were discovered in 1955 by Leo Sternbach in 1955 and made available by 1960, rising as the most sought after medications by 1977. Currently, they are classified as 0 substances and available only by prescription.

What are benzodiazepines used for?

Benzodiazepines were initially used in Japan to treat anxiety and depression, after which their use gradually spread to other parts of the world. A survey in Italy proved their efficacy in treating depression; they quickly rose in rank as prominent anti-depressants throughout the states. Benzodiazepines also help in the treatment of insomnia and hypersomnia, two major sleep disorders.

Due to their sedative properties are used in surgical procedures as an additional component besides general anaesthesia. Going as far as being used before minor surgeries with diagnostic procedures, the use of benzodiazepines has extended over time as muscle relaxants and in the treatment of nausea and vomiting. Additionally, their anxiolytic effects make them effective medications for panic attacks, alcohol withdrawal and drug associated agitation. Medical practitioners also use them off-label for the treatment of bipolar disorders.

How do they work?

Gamma-Aminobutyric Acid or GABA is an inhibitory neurotransmitter that blocks impulses between the nerve cell and brain. The primary function of GABA is to calm and relax the nervous system.

Low levels of GABA in the brain results in anxiety, muscle pain and even epileptic symptoms. Benzodiazepines work through the GABA receptors in the brain cells to optimize their functions.

GABA receptors consist of 5 protein subunits arranged around a ring. It consists mainly of two alpha subunits, two beta subunits and one gamma subunit. The function of these receptors is to regulate neuronal hyperpolarization of the cell. Benzodiazepines bind to the GABA receptors to increase the affinity of the GAB cells. They even change the receptor structure in such a way to prevent its reabsorption back to the body. This increases GAB cells’ concentration that induces anxiolytic, hypnotic and muscle reactant effects with other functions.

Benzodiazepines change their effects based on their binding with different subunits. GABA receptors contain alpha-1, alpha-2 and alpha-3 receptors subunits with gamma subunits. Anxiolytic effects are achieved on binding to the alpha-2 and alpha-3 subunits, while hypnotic effects are more prominent on activation of the alpha-1 subunit.

Types and Mechanism of action of Benzodiazepines

Benzodiazepines are primarily available in tablet form for oral consumption. However, intramuscular and intravenous injections of the medication are also available. People facing difficulties in swallowing or having severe stomach problems can consume the drug through Intranasal and interseptal forms or rectally. It is noteworthy that these routes apply to selected medications. While some medicines respond better when injected intramuscularly, some act more quickly to interseptal methods. The majority of benzodiazepines, however, react comfortably to oral ingestion.

There are two types of Benzodiazepines based on their elimination and rate of absorption. Elimination half-life is the time required for the plasma concentration of a drug to decrease to 50% during the elimination phase. In simple words, it is the time taken by the drug in the plasma to reduce to half of its original quantity. It takes around five elimination Half-lives for complete elimination from the body.

Based on this elimination half-life, benzodiazepines are of 3 types – Short-acting, intermediate-acting and long-acting. Short-acting Benzos have a half-life of 1-12 hours while interned ones get dispelled between 12-40 hours, with that of the long-acting ones extending up to 250 hours. Benzos are additionally classified based on their potency into low medium and high strength. Usually, the strength of the drug is inversely proportional to the half-life of Benzodiazepines, i.e. short-acting medications have a higher potency and vice versa.

Short-acting medications like Alprazolam and Clonazepam can treat anxiety and panic disorders. Lorazepam can manage acute agitation and mania and patients with convulsions. Midazolam used preoperatively for sedation purposes is short-acting. Meanwhile, Diazepam has a longer life and can treat sedation, myorelaxation and anxiolytic effects. It can be administered through all routes, including oral, intramuscular, interseptal and rectal.

Are Benzodiazepine controlled Substances?

Initially, Benzodiazepines have not been controlled substances, but the growth rate of misuse and addiction associated with this medication has forced countries worldwide to declare it a controlled substance. A study conducted on benzodiazepines has shown that of 30 million adults on Benzos, almost 5 million did not have a prescription or misused them. Noticeably, youngsters between the ages of 18-25 had the highest rate of misuse in comparison to other age groups.

A lot of things can go wrong with prolonged or injudicious use of the medications. Opioid users often crush them to attain their hypnotic and anxiolytic effects. Crushing increases the concentration of the drug in the bloodstream leading to overdosing symptoms like respiratory depression, coma and even death. The medication’s high tolerance levels have prompted FDA to declare it a controlled substance and place it under the Schedule IV medication list.


Benzodiazepines can effectively treat various psychiatric and neuromuscular disorders by working on the nerve receptors in the Central Nervous System. If misused or overused, it can increase the severity of your health conditions as well. Benzodiazepines, like any psychostimulant, have a withdrawal period. The longer their use is extended, the greater the severity of the withdrawals symptom. Additionally, long term use can the drug dependence and neurotoxicity risk associated with the medication. It is vital to use them on a short term basis strictly by the guidance of your practitioner. It is also important to discuss your systemic history with him before their use to avoid risks of drug interactions associated with the medication.