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Barbiturates: effects, mechanisms of action and toxicity

Barbiturates: effects, mechanisms of action and toxicity

June 24, 2024

Anxiety and the different problems it can cause in our lives are widely known today. But while it is considered that our current pace of life facilitates the appearance of these types of problems, the truth is that anxiety is known since ancient times.

Throughout history they have tried to create different techniques and effective substances against anxiety. One of the most successful types of psychotropic drugs until the arrival of benzodiazepines have been the barbiturates .

  • Related article: "Types of psychotropic drugs: uses and side effects"

Barbiturates: what are they?

Barbiturates are a type of psycho-psychoactive drug , that is, it has calming and depressant effects on the central nervous system. These drugs are derivatives of barbituric acid, which was first synthesized by Adolf von Baeyer in 1863. However, the first drugs properly known as barbiturates did not emerge until 1903, under the guidance of Emil Fischer and Josef von Mering. They are considered the first psychotropic drugs with hypnotic-sedative effects.

The performance of barbiturates on the nervous system causes a high level of sedation, relaxing and decreasing muscle and mental activity. They have a great effect as hypnotic, anesthetic and analgesic . In addition, they are useful in the treatment of seizures and other motor symptoms.

On the other hand, barbiturates they generate alterations in the mood , as mild sensations of euphoria. Due to its effectiveness in reducing anxious symptoms, they were for a time the treatment of choice for the symptoms of anxiety, depression and insomnia.

  • Related article: "Benzodiazepines (psychodrugs): uses, effects and risks"

Risks of its consumption

The barbiturates, although highly effective in the treatment of certain symptoms and problems, are highly toxic and have a high level of danger.

Despite its effectiveness, the use of barbiturates It poses a high risk to health, generating dependency with great ease . In addition, doses that are therapeutic and those that are toxic are very close, which can cause poisoning and even overdose.

An overdose of barbiturates can lead to death in 1 out of 4 cases. In fact, there are many deaths linked to the overdose of these medications , such as Marilyn Monroe.

Currently, barbiturates have been ousted by benzodiazepines , which enjoy a higher level of security, at the same time that they do not generate so much dependence or provoke such serious side effects. Despite this, barbiturates continue to be used medically in specific cases in which other substances are not effective, such as anesthesia in surgical interventions or in neuropsychological explorations (always with a high level of control).

The risks multiply if the barbiturates are mixed with other substances. In combination with depressant substances can cause respiratory failure. Its combination with alcohol, antihistamines and depressant drugs they enhance depressant effects, and the result can be fatal. On the other hand, the taking of activating substances in the quest to counteract the effects of barbiturates can in turn generate cardiac problems.

Another risk of great importance it has to do in cases of pregnant women and nursing mothers . And is that barbiturates, highly liposoluble, can be transmitted through the placenta and breast milk. Likewise, an overdose can be dangerous for the life of the fetus, and an abortion may occur.

Some side effects

The consumption of these substances can cause a series of highly relevant side effects , which can even lead to death. Some of these effects may be the following.

1. Excessive sedation

Barbiturates have come to be used as an anesthetic due to their powerful sedative effect. While this can sometimes be sought, it can be a detriment to the proper functioning and personal performance to cause excessive sleepiness that reduces the physical and mental capabilities of the individual. May cause mild paralysis and tingling in different parts of the body.

2. Uncoordination of different functions

The consumption of barbiturates can cause the existence of problems of physical coordination, being more difficult to walk or even talk . You should not drive under the effects of this type of medication even if you do not get drowsy.

3. Cardiorespiratory problems

The barbiturates are psychopharmaceuticals of great power as depressants of the nervous system, as we have just commented. However, this depression can generate respiratory problems, and even in extreme cases there is a risk of entering cardiorespiratory arrest .

4. Behavioral disinhibition

Although, as a general rule, barbiturates generate depressant effects on the nervous system that are sedated in some people, they can produce a high level of behavioral disinhibition, which can lead to actions that under normal circumstances would not be carried out. In fact, they have been used as supposed "sera of the truth".

5. Risk of dependence

The addictive potential of this type of substances is very high , generating dependency with great ease. It is also easy to commit abuse in their consumption, which is especially dangerous with this medication. The main reason is the high level of tolerance that tends to cause, which makes it necessary every time a greater quantity to achieve the same effects as in the first shots.

6. Withdrawal syndrome

When a person with dependence on barbiturates ceases their use abruptly can suffer withdrawal syndrome. In the case of abstinence from barbiturates, it is common to generate the opposite effects to the consumption of the substance.

Specifically, it is easy to find restlessness, anxiety, aggression, gastrointestinal symptoms Insomnia or seizures. Hallucinations and delusions may also arise. It can cause a dangerous voltage drop for survival. In fact, in some cases the withdrawal syndrome can be deadly. That is why both the taking and the cessation of the use of these drugs have to be prescribed with special caution, withdrawing gradually.

Mechanism of action

The operation of barbiturates is based mainly on the facilitation of the action of gamma-aminobutyric acid or GABA, which reduces the overload of the nervous system by making it difficult for nerve impulses to occur and transmit.

This favoring of GABA is carried out through the action of the drug in the ion channels sensitive to said hormone in the brain. Specifically hinder the entry of sodium into the neuron , while facilitating the entry of chlorine into the cell.

Types of barbiturates

Barbiturates, like other medications, can be classified into several groups depending on how long they take to take effect and how long the effects last. However, even when the effects end, their characteristics cause them to remain in the organism for a long time. We can identify 4 types of barbiturates .

1. Ultrashort action

Ultra-short-acting barbiturates They are characterized by having a half-life of several minutes duration , starting its effects seconds after consumption. Within this group we can find thiopental and methohexital.

2. Short action

They are known as short-acting barbiturates such as hexobarbital, pentobarbital or secobarbital, which start their effects between ten and fifteen minutes after consumption to last for around 3 or 4 hours .

3. Intermediate action

Intermediate action barbiturates usually take about an hour to take effect, lasting between 6 and 8 hours . Within this type of barbiturates we find one of the best known and used in various procedures such as the Wada test, amobarbital.

4. Long action

Primidone and phenobarbital are some of the examples of long-acting barbiturates, which usually take more than an hour to take effect, but which nonetheless tend to last around 12 hours.

Uses and applications

Although they have now been replaced by other substances in the treatment of most conditions, barbiturates continue to be used in certain cases. Some of the uses that these substances have in the past or have had in the past are reflected below.

Neuropsychological exploration

Barbiturates are used in some neuropsychological evaluation procedures. An example of this is the Wada test , in which amobarbital sodium is used to sedate a specific area of ​​the brain and determine the functionality of areas linked to aspects such as laterality, memory or language.


Some barbiturates are used both to start and to keep patients anesthetized during different surgical interventions. It is one of the main current applications.


One of the indications of certain types of barbiturates is its use in cases where convulsions appear s , since they help to control motor symptoms thanks to its sedative effect and GABA reinforcement, which helps to inhibit the discharge of nerve impulses.

Injuries and cerebral accidents

The barbiturates are used to control and decrease the effects of cerebral infarcts , as well as the edemas produced by different traumatic brain injuries.


Although other types of sedatives such as benzodiazepines are currently used, barbiturates they have been used in the past as sleeping pills .

  • Related article: "Combat insomnia: 10 solutions to sleep better"


As with insomnia, other types of substances are currently used (the most frequent benzodiazepines and some antidepressants) to treat anxiety, but in the past barbiturates were the main substance used as an anxiety treatment .

Bibliographic references:

  • Gómez-Jarabo, G. (1999). Pharmacology of behavior. Basic manual for psychotherapists and clinicians. Madrid: Psychology synthesis.
  • Gómez, M. (2012). Psychobiology CEDE Preparation Manual PIR.12. CEDE: Madrid
  • Morón, F.G .; Borroto, R .; Calvo, D.M .; Cires, M .; Cruz, M.A. and Fernández, A. (2009). Clinical pharmacology. Havana: Editorial Medical Sciences; 1-30
  • Salazar, M .; Peralta, C .; Pastor, J. (2011). Manual of Psychopharmacology. Madrid, Panamericana Medical Publishing House.

Barbiturates - Mechanism, Uses, Adverse effects and Classification in Detail. (Urdu/Hindi). (June 2024).

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