Tranquilizers (Drugs): Definition, Classification and Examples

Tranquilizer, the term first used by F. F. Yonkman in 1953, refers to a drug which was designed for the treatment of anxiety, tension, fear, and other disturbances of mind, in order to reduce state of anxiety and tension. Let’s look into the concept more closely with some examples and important questions. 

Keyterms: Tranquilizer, anxiety, tension, fear, central nervous system, dopamine, neurotransmitter dopamine, brain, drug

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Definition of Tranquilizers

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Tranquilizers are central nervous system depressants that bring about a calming effect and induce mild sedative effects. Most of these drugs are derivatives of Barbituric acid-like Veronal, Mytal, Nembutal, Luminal, Seconal.

They are designed for the treatment of:

• Anxiety
• Tension
• Agitation
• Fear
• Disturbances in the mind

Specifically, to reduce states of anxiety and stress.

Tranquilizers

Mode of action- Acts on the central nervous system by blocking the neurotransmitter dopamine in the brain.

Read More: Analgesics

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Classification of Tranquilizers

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Major Tranquilizers

Drugs that are used to reduce psychic symptoms. These are also called neuroleptics which were developed to treat psychiatric disorders like schizophrenia. Moreover, these drugs also combat hallucinations and other delusions and are usually prescribed for long terms. The major tranquilizers include:

1. Phenothiazine Derivative

Ex: Chlorpromazine, Prochlorperazine, Trifluoperazine, Thiothiazine

2. Butyrophenones Derivative

Ex: Haloperidol, Trifluperidol

3. Rauwolfia Alkaloid

Ex: Reserpine

4. Dibenzodiazepine derivative

Ex: Clozapine

5. Thioxanthine derivative

Ex: Thioxanthenes

Minor Tranquilizers

The drug is used to treat mild symptoms of anxiety, tension or neurons. These are also known as anxiolytics which are used for sedation and to treat anxiety. Nowadays, these drugs are called anti anxiety medications.

1. Benzodiazepines derivative

Ex: Diazepam, Chlordiazepoxide, Lorazepam, Nitrazepam

2. Carbonate derivative

Ex: Meprobamate

3. Miscellaneous

Ex: Hydroxy Lithium Carbonate

Read More: Decomposition Reaction

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Some of the Drug Profiles

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Chlorpromazine

2-chloro-10-(3-dimethyl aminopropyl) phenothiazine.

Chlorpromazine

Physical Properties

• Surface nature and colour: It is a white coloured powder
• Taste and odour: It is bitter and slightly odour
• Solubility: It is practically soluble in water and sparingly soluble in alcohol. 
• Stability and storage: It is affected by light. Should be stored in well closed containers. 

Uses

• It is used as an antipsychotic agent
• It is used in the treatment of Schizophrenia, mania
• It is used to produce pre and postoperative sedation
• It also reduces salivary and gastric secretion
• It is used to treat mania
• It is used as a mild local anaesthetic agent

Brand name

• Chlorazine, Copamide, Chlorzen plus, Clozine

Official Preparation

• Chlorpromazine Tablet
• Chlorpromazine Injection
• Chlorpromazine Elixir 

Haloperidol

4-[4-(4-Chlorophenyl)-4-hydroxy piperidin-1-yl]-1-(4-fluorophenyl) butan-1-one.

Haloperidol

Physical Properties

• Surface nature and colour: It is a white and faint yellowish, amorphous powder
• Taste and odour: It is a tasteless and odourless compound
• Solubility: It is practically insoluble in water and sparingly soluble in alcohol
• Stability and storage: It is affected by light and air. Hence it should be stored in an airtight resistant container.

Uses

• It is used as an antipsychotic agent
• It is used in the treatment of schizophrenia, mania and anxiety
• It is used to treat tetanus
• It is used as tranquilizing agent
• It is used as a mild local anaesthetic agent
• It potentiates the actions of central nervous system depressant like analgesics, barbiturates, and anaesthetics

Brand name

• Halidol, Combidol

Official Preparation

• Haloperidol Tablet
• Haloperidol Injection
• Haloperidol Elixir
• Haloperidol Oral Suspension
• Haloperidol Capsule

Prochlorperazine

Prochlorperazine

Physical Properties

• Surface nature and colour: It is a white coloured powder
• Taste and odour: It is bitter and slightly odour
• Solubility: It is very soluble in water and freely soluble in alcohol and organic solvent.
• Stability and storage: It is affected by light. Hence it should be stored in an airtight resistant container.

Uses

• It is used as an antipsychotic agent
• It is used in the treatment of Schizophrenia, mania
• It is used to produce pre and postoperative sedation
• It also reduces salivary and gastric secretion
• It is used as tranquilizing agent
• It is used as a mild local anaesthetic agent

Brand name

• Compazine, Stemetil

Official Preparation

• Prochlorperazine Tablet
• Prochlorperazine Injection
• Prochlorperazine Mesilate

Diazepam

7-Chloro-1,3-dihydro-1-methyl-5-phenyl-3H-1, 4-benzodiazepin-2-one

Physical Properties

• Surface nature and colour: It is a white and faint yellowish, amorphous powder
• Taste and odour: It is a tasteless and odourless compound
• Solubility: It is sparingly soluble in water and soluble in alcohol
• Stability and storage: It is affected by light and air. Hence it should be stored in an airtight resistant container.

Uses

• It is used as an anti-anxiety agent
• It has a good muscular relaxation property
• It is used as an anti-convulsing agent
• It is used as pre anaesthetics medication
• It is used as a sedative and hypnotic agent
• It is used in the treatment of acute alcohol poisoning

Brand name

• Diazepam, Calmpose, Valium

Official Preparation

• Diazepam Tablet
• Diazepam Injection
• Diazepam Elixir
• Diazepam Solution
• Diazepam Capsule

Tranquilizers are drugs that act on the nervous system. They affect the transmission of messages that happen from nerves to receptors.

Also Read:

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Examples of Tranquilizers

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Tranquilizers come in a variety of forms. They operate following their mechanisms.

Non-adrenaline, for example, is one of the neurotransmitters involved in mood swings. If the non-adrenaline level is low, the person will experience depression because the signal sending activity is reduced. In the aforementioned situation, antidepressant medications are required. Antidepressants work by inhibiting the enzymes that catalyse the breakdown of noradrenaline. 

When the enzymes are inhibited, this neurotransmitter is slowly metabolised, allowing it to activate its receptor for longer periods and counteracting the effect of depression. This class of drugs includes iproniazid and phenelzine.

For example, to alleviate anxiety, we use tranquilizers such as chlordiazepoxide and meprobamate. In addition, Equanil is used to control hypertension and depression.

Read More: Types of Chemical Reaction

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Antiseptics

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• They are applied to the living tissue like wounds in order to prevent the growth of microbes and free the skin from any disease.
• One of the examples of antiseptic is Boric acid which is used for eyes.
• Another most popular disinfectant used these days is dettol which is a mixture of chloroxylenol and terpineol. 
• Both antiseptics and tranquilizers are significant for healthy survival of human beings.

Read More: Randicity

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Things to Remember

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• The topic Tranquilizers is covered in Unit 16 i.e, Chemistry in Everyday Life of NCERT Class 12 Chemistry.
• The term "Tranquilizers" is deceptive. However, excessive use of it must be avoided.
• An overdose of tranquilizers will result in a serious neuro problem and should be avoided as much as possible.
• Tranquilizers, like the two sides of a coin, can do both good and harm. So it is up to us to ensure that our lives are up to standard and that we do not overmedicate