Classification Of Drugs

Introduction to Drugs

Drugs, the word is not new to us. However, the word generally creates a frightful response amongst many. So far we have heard that drugs are the substance of addiction and a reason for the spoiled generation. This is mainly because people have been abusing the substance which has led to the death of even popular people as well.

Yes, they are addictive but did you know that all of them are not harmful. Biologically speaking, drugs mostly target our brains and switch the mood and physiological conditions of our bodies. However, since there are various types of drugs including legal as well as illegal drugs, the latter is causing most of the problems.

Having said that, on this page we will be discussing mainly the legal drugs and their classifications.

Table of Content

What are Drugs?

By definition, drugs are chemical substances that affect or alter the physiology when taken into a living system. They can either be natural or synthetic.

Chemically, they are low atomic mass and molecular mass structures. When a drug is therapeutically active and is used for the diagnosis, treatment or prevention of a disease, it is called medicine (legal drugs). They target the macromolecules inside the body and generate a biological response. Most of them interrupt the nervous system (especially the brain) for the generation of a proper biological response. However, they can be toxic in higher doses and generally referred to as lethal doses.



Classification of Drugs

Classification of drugs can be done on the basis of certain criteria. Some of them are given below.

Classification of Drugs

Classification of Drugs on the basis of the Pharmacological Effect:

  • How a drug or medicine affects or influences the cells of an organism is referred to as the pharmacological effect. Different types of drugs have various pharmacological effects on an organism.
  • For example, an analgesic reduces pain while an anti-inflammatory drug reduces the inflammation of the body. Thus, drugs can be classified based on the pharmacological effect.

Read more about Analgesics – The drug to relieve pain.

Classification of Drugs on the basis of Drug Action:

  • Different drugs act differently i.e., each drug has its own way of generating a response called drug action.
  • Drug action is more specified according to how it generates a response. For example, there are lots of medicines to treat hypertension but each type of drug has different drug actions.
  • All hypertension medicines reduce blood pressure but in a different pathway.

Classification of Drugs on the basis of Chemical Structure:

  • This is a common classification of drugs. Generally, drugs that have the same drug action and pharmacological effect have a basic skeletal structure and a minute variation in the branching.
  • This is why some drugs have more potential than others. For example, all sulphonamides have the same skeletal structure.

Classification of Drugs on the basis of Molecular Targets:

  • Drugs target the macromolecules inside the body to generate a biological response.
  • Such macromolecules are called target molecules or drug targets. Drugs that have the same mechanism of action will have the same target.
  • This basis for the classification of drugs is more helpful during clinical trials.

For more details on the classification of drugs with video lessons, you can download BYJU’S – The Learning App.

Frequently asked questions-FAQs

1. Name two strongest drugs.

Ans: Oxymorphone and hydromorphone are the strongest opioids.

2. Define mind altering drugs.

Ans: Various psychoactive substances that are used for their perception and mood altering effects are called mind altering drugs.

3. Give some examples of psychoactive substances.

Ans: LSD, caffeine, cocaine, alcohol.

4. Which drug is the most widely used mind altering drug in the world?

Ans: Alcohol.

5. Caffeine is a drug. Why?

Ans:  It stimulates the CNS and causes increased alertness.

Read more:

Test your Knowledge on Classification of drugs!


Leave a Comment

Your Mobile number and Email id will not be published.



  1. those website have impressed me so much keep it up God will strengthen you people