Benzodiazepines

Benzodiazepines are a family of psychotropic drugs that produce a hypnotic and sedative effect. They are central nervous system (CNS) depressants that are typically used as minor tranquilizers. Since the 1960s, benzodiazepines have been a popular medication and safer option than barbiturates in treating symptoms associated with anxiety and sleep disorders. Commonly prescribed and well-known benzodiazepines include alprazolam (Xanax), diazepam (Valium), chlor-diazepoxide (Librium), temazepam (Restoril), and [Page 120]triazolam (Halcion). As a result of the beneficial anxiolytic and soporific properties, benzodiazepines have a high potential for abuse and dependence. They are among the most commonly abused prescription drugs.

There are many therapeutic uses for benzodiazepines as they safely manage and treat a variety of conditions. Benzodiazepines are most predominantly prescribed for anxiety, elevated stress in fear-evoking situations and other symptoms associated with anxiety disorders (i.e., panic attacks, generalized anxiety disorder, post-traumatic stress disorder). Benzodiazepines are often used to treat insomnia and other sleep disorders. Certain benzodiazepines have been approved as anticonvulsants for seizures caused by forms of epilepsy and delirium tremens related to alcohol dependence. Other therapeutic uses include myorelaxants (muscle relaxation), medication before surgical procedures (as a light anesthetic), and sedation of patients on mechanical ventilation in intensive care. When used correctly, benzodiazepines can be advantageous across a wide range of symptoms and disorders.

Although there are as many as 50 benzodiazepines marketed worldwide, they all have the same mechanism of action, which is associated with affecting the neurotransmitter gamma-aminobutyric acid (GABA). Therefore, all benzodiazepines produce a similar effect within a range of intensity. The variation of intensity among the different benzodiazepines is due to speed of elimination (half-life) and duration of effect. They can be divided into three groups: short-acting, intermediate-acting and long-acting. This classification is based on the half-life of each drug. The half-life is the time it takes for the substance's concentration in the blood to decrease to half its initial level after a single dose. Consequently, the half-life determines the length of time the drug is active (duration of effect).

The three groups are used to determine which benzodiazepine is the best fit for treatment. Short-acting benzodiazepines have a half-life of less than 12 hours and are best utilized for the short-term management of insomnia and related symptoms. These include estazo-lam (ProSom), temazepam (Restoril), and triazolam (Halcion), which facilitate sleep and assist the individual in staying asleep. Due to the short half-life, they yield little residual effect (hangover) but are quicker to produce tolerance. The intermediate-acting compounds are characterized by a half-life of between 12 and 24 hours, and long-acting benzodiazepines have a half-life greater than 24 hours. The intermediate- and long-acting benzodiazepines, such as lorazepam (Ativan), clonazepam (Klonopin), and diazepam (Valium), are more generally used as anxiolytics. Long-acting compounds accumulate in the bloodstream with use over time. This buildup may ease withdrawal symptoms (which often mimic the initial complaint) or enhance the effect as the drug is compounded. Regardless of the length of the half-life, all benzodiazepines have potential for tolerance and sometimes dependence.

Although the therapeutic advantages are great, benzodiazepines produce side effects. Common side effects, though often mild, include drowsiness, dizziness, weakness, confusion, and other cognitive impairments. Benzodiazepines can also produce slurred speech, ataxia, and impairment of psychomo-tor skills. Drug interactions can occur, and when used in combination with other substances, the latter mentioned side effects are compounded. A fatality resulting from an overdose of benzodiazepines alone is rare, but the risk of death is greatly increased when benzodiazepines are combined with other CNS depressants (e.g., alcohol, barbiturates).

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