Drugs and Their Classification


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Define Drugs and Their Uses

Drugs are chemicals of low molecular mass which interacts with targets and bring about the response. When drugs are used for therapeutic purpose, it is known as medicine. Medicines are used in diagnosis, prevention and treatment of diseases. Some drugs are also used as poisons to target cancer cells, this is known as Chemotherapy.

Classification of Drugs

Drugs are classified as follows:

On the basis of pharmacological effect

These types of drugs are used by doctors for the treatment of a particular type of problem. For example, analgesics are used as pain killers, antiseptics are used to treat against microorganisms or any infection.

On the basis of drug action

It is used to target a particular biochemical process. Such as, antihistamines inhibit the action of histamine which causes inflammation in the body. There are various ways in which action of histamines can be blocked.

On the basis of chemical structure

Drugs classified on the basis of chemical structure often have similar structure and similar pharmacological activity. For example, sulphonamides

On the basis of molecular targets

These drugs interact with biomolecules such as carbohydrates, lipids, proteins, and nucleic acids. Drugs possessing some common structural features may have the same mechanism of action on targets.

Different Types of Drugs

  • Depressants are used to suppress or slow down the brain activity. It is used to control the central nervous system to give the feeling of calmness. This includes barbiturates such as phenobarbital, benzodiazepines such as alprazolam and gamma hydroxybutyrate (GHB). They are consumed to relieve anxiety

 Phenobarbital 1 and Alprazolam

Fig. 1(a) Phenobarbital 1(b) Alprazolam

  • Stimulants are drugs that are used to accelerate the activity of the central nervous system. They make us feel more energetic, alert as well as focused. Such as cocaine amphetamine etc. 

 Structure of cocaine

Fig. 2. Structure of Cocaine

  • Hallucinogens are also known as Psychedelics. They also target the nervous system and alters the feeling of reality, space, and time. When a person consumes hallucinogens, he or she will imagine the things which do not exists. For Example, psilocybin (found in magic mushrooms), lysergic acid diethylamide (LSD), peyote, and dimethyltryptamine (DMT).

Structure of psychedelics

Fig. 3. Structure of Psychedelics


 Structure of morphine and heroin

Fig. 4. Structure of Morphine and Heroin

  • Inhalants are drugs that are consumed through inhalation. Inhalants are consumed by children and adults as drug adductors. It includes paint, glue, paint thinners etc. 

  • Cannabis is obtained from plant source. It acts on cannabinoid receptors in the brain. It is abused in various forms including bhang, ganja, and hashish oil.

Frequently Asked Questions(FAQs)

Q1. Is Xanax considered a stimulant?

Sol. Xanax is a depressant but not a stimulant

Q2. Is Ativan considered a controlled substance?

Sol. Ativan is a tranquilizer. Yes, it is a schedule 4 control substance.

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Drugs and Thier Classification


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