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When a person has anxiety and resorts to pharmacological treatment, he is likely to receive an anxiolytic.
Anxiolytic are drugs that have been used for many years to reduce anxiety levels and induce a state of relaxation in the person.
In this article, we will learn about the four main types of anxiolytic that exist, according to their properties and indications. We will know what each group is indicated for, what its mechanism of action is, characteristics, side effects and differences between them.
Types of anxiolytics
Anxiolytic are drugs that are used to reduce anxiety levels. Thus, they are especially suitable for anxiety disorders, although they also have other indications.
That is, they are used for anxiety disorders, but also for different conditions that are accompanied by an anxious component (for example, a depressive disorder with anxious symptoms, an adaptive disorder...).
There are different types of anxiolytic, depending on their properties, mechanism of action, indications, side effects... Let's look at the characteristics of the four large groups and the differences we find between them.
The first anxiolytic drugs that were marketed were barbiturates; these drugs are derived from barbiturate acid, and cause drowsiness and sedation, since they depress the Central Nervous System (CNS).
They were the first used to treat anxious symptoms and cause relaxation. However, they were later ousted by benzodiazepines, since barbiturates were unsafe (they produced overdoses easily). In fact, barbiturates were even used in the United States for the execution of people sentenced to death (as part of the lethal injection).
Currently, barbiturates are not used for cases of anxiety, and instead are used as antiepileptics (for example, phenobarbital and primidone). In low-developed countries, phenobarbital is the only antiepileptic drug available to them. This, in particular, is the most prescribed barbiturate in the world.
Continuing with the types of anxiolytics, we find the anxiolytics after the barbiturates: the benzodiazepines. Its mechanism of action is as follows: these are indirect agonists of the GABA A receptor that act on the cortex and the limbic system.
That is, what benzodiazepines do, is increase the concentration of GABA in the brain; GABA is the depressing neurotransmitter par excellence. That is why an increase in their concentration has relaxing effects. Benzodiazepines are also used as muscle relaxants, not just as anxiolytics.
Although benzodiazepines were the "star" anxiolytics for many years, and were used in many cases, they are currently not drugs of choice for any anxiety disorder. They are still used, yes, but many times inappropriately, since it was observed how they were highly addictive drugs, which created dependence in patients.
It is paradoxical as even though all this is known, benzodiazepines are currently the most prescribed psychotropic drugs as anxiolytic drugs.
It is because of all the above, so they should be used with great caution and always under medical prescription; ideally, they should be used for a certain period of time, but not for many months. This at the moment of truth is not real, since there are many people who have been taking them for years.
Having said that, let's get to know the indications of benzodiazepines: they are prescribed for anxiety disorders, such as Generalized Anxiety Disorder (GST), Panic Disorder (PT), Social Phobia (FS) and adaptive disorders.
On the other hand, due to their pharmacological properties, they are types of anxiolytics also indicated for depression (especially alprazolam) and insomnia (triazolam and tepazepam). Finally, they are also used for Bipolar Disorder (TB) (clonacepam) and alcoholic abstinence.
These types of anxiolytic, in turn, are classified into subtypes according to their half-life. The half-life (or action) of a drug means how long it takes to metabolize in half, that is, it is a parameter that contemplates the time of action of the drug.
Thus, the shorter the half-life, the faster the drug acts in the body. In other words, short-acting benzodiazepines produce their effect more immediately than medium- or long-acting benzodiazepines, which produce it over a longer period of time. This means that the effect of long-acting benzodiazepines lasts longer than that of the other types.
In this way, we find benzodiazepines of three types: short half-life (or short-acting), middle- or intermediate-life (or middle-acting) and long-life (or long-acting). Let's look at examples and characteristics of each one:
- Short action
Examples of short-lived benzodiazepines we find: triazolam, midazolam, bentazepam, brotizolam.... As characteristics, we know that short-lived benzodiazepines are the ones that create the most dependence (compared to half- and/or long-lived ones). In addition, they are the ones that have the most side effects.
- Average action
Middle-life benzodiazepines we find: alprazolam, lorazepam, bromazepam, oxacepam... This second type has a number of "intermediate" side effects between short-acting and long-acting side effects.
- Long action
Finally, long-acting benzodiazepines are, for example: clonazepam, diazepam, flurazepam, medazepam... These have a lower risk of dependence; on the other hand, they present a risk of daytime sedation (since their effects last longer; they are the most "powerful").
As for the side effects of these types of anxiolytics, benzodiazepines can produce:
- risk of addiction,
- withdrawal syndrome (anxiety, rebound insomnia...),
- impairment of memory (difficulties of evocation, anterograde amnesia...), as well as attentional,
- and performance difficulties (slowdown).
As adverse reactions, we find a paradoxical reaction in the elderly.
3. Serotonin anxiolytics
Serotonin anxiolytics, other types of anxiolytics, consist of partial agonists of a serotonin receptor (5HT1A). This means that they increase the concentration of serotonin in the brain, a neurotransmitter related to mood. Unlike benzodiazepines, serotonergic anxiolytics do not interact with GABA.
As a typical example of this group, we find buspirone (trade names: Ansial or Buspar). Buspirone is the pharmacological treatment of choice for Generalized Anxiety Disorder (GSA). For TAG, in addition, venlafaxine (a 4th generation antidepressant) is also considered a choice.
They are indicated for the TAG and to treat anxiety in substance abuse and alcoholism (by not interacting with alcohol).
4. Short-acting non-benzobenziazepines
As the fourth group of types of anxiolytics, we find this type of hypnotics, indicated to treat insomnia. They are easy to memorize because they all start with "Z": zaleplón, zolpidem and zoplicona. These are GABA agonists, which act only in regions where they induce sleep.
Like benzodiazepines, these types of anxiolytics can be classified according to their half-life: thus, zaleplón and zolpidem are short half-lived, and the zoupicon are long-lived. The advantage of this group of anxiolytics is that they have fewer side effects than benzodiazepines.
Although anxiolytics are the drugs "by excellence" to treat different anxiety disorders, antidepressants are another group of drugs that also have anxiolytic properties, and therefore are also indicated to treat this type of condition.
It will all depend on the diagnosis of each patient, their needs and personal characteristics. However, we must remember that a psychopharmacological treatment should always be accompanied by a psychological treatment.
- Lopez, J.M. (2019). History of barbiturates. Pharmaceutical reviews.
- Stahl, S.M. (2002). Essential psychopharmacology. Neuroscientific bases and clinical applications.
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