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What are Drugs (Medicines) ?

Drugs or medicines are the chemical substances which are used in the prevention, diagnosis and treatment of diseases.

Classification of some common drugs

drugs classification


  • Antipyretics are the drugs which are used to reduce fever i.e. reducing the body temperature to the normal.
  • Examples : aspirin, paracetamol, etc.


  • Paracetamol is preferred over aspirin, since aspirin gets hydrolysed to salicylate in stomach that may causes bleeding and gastritis.


  • The drugs which are used to relieve or decrease pain (without the loss of consciousness) are called analgesics.
  • These are also called as pain killers or pain relievers.
  • Examples : aspirin, novalgin, analgin, etc.


Antipyretics and analgesics

  • Some drugs can be used to reduce fever as well as to relieve pain, such drugs are called antipyretic and analgecics.
  • Aspirin is a common example of antipyretic and analgesic drug.


  • Antibiotics are chemical substances produced by various micro-organism (such as bacteria, fungi and molds) and are capable of destroying or suppressing the growth of other microorganism.
  • Examples : penicillin, chloramphenicol, etc.
  • Antibiotics which are effective against several different types of harmful micro – organism are called broad spectrum antibiotics. eg. chloramphenicol, tetracycline, etc.


  • Chloramphenicol is used to cure typhoid, pneumonia, meningitis,etc.


  • Antiseptics are the chemical substances which prevent the growth of micro-organism or kill them ( in wounds, cuts, etc.) but are not harmful to the human beings.
  • It is directly applied into the infected parts i.e. they are usually of external use.
  • Examples : Dettol, savlon, 0.1% phenol, boric acid, etc.

dettol structure

Disinfectants : Chemical substances which are applied to inanimate objects like instruments, utensils, clothes, etc. Most of them are harmful to the living tissues and thus cannot be used on the skin. Examples : 1% phenol, chlorine, H2O2, etc.

Sulpha (sulfa) drugs

  • Sulpha drugs are group of synthetic antibiotics derived from sulphanilamide.
  • Sulpha drugs were the first chemical substances systematically used to trat and prevent bacterial infections in humans.
  • Their use has diminished because of the availability of antibiotics that are more effective and safer.
  • Sulpha drugs are still used, but largely for treating urinary tract infections, dysentery and preventing infection of burns.

Sulpha (sulfa) drugs


  • Tranquilizers are the chemical substances used to cure mental diseases.
  • In short, a tranquilizer restores the peace of mind.
  • These are also called psycho – therapeutic drugs.
  • Examples : Barbituric acid, Diazepam, alprazolam, clonazepam, etc.

Anti- allergic ( Antihistamines)

  • Antihistamines are the drugs used to treat allergies.
  • They work by preventing the effects of a substance called histamine, which is produced by the body. Histamine can cause itching, sneezing, runny nose, and watery eyes.
  • Examples : fexofenadine, citirizine, etc.


  • Bronchodilators are the drugs that make breathing easier by relaxing the muscles in the lungs and widening the airways (bronchi).
  • They are often used to treat long-term conditions where the airways may become narrow and inflamed, such as- asthma.
  • Examples : salbutamol, salmeterol, formoterol, etc.


  • Antacids are the chemical substances which can reduce or neutralize the acidity in stomach and raise the pH to appropriate level.
  • Antacids contain weakly basic chemicals such as magnesium hydroxide i.e. Mg(OH)2, Aluminium hydroxide i.e. Al(Cl)3, magnesium carbonate i.e. MgCO3, etc.

Objective Questions

1. Drugs which helps to reduce anxiety and brings about calmness is

a. Analgesic  c. tranquilizer

b. Antibiotic d. Antacids

2. Which of the following is an analgesic drug ?

a. Penicillin c. Chloramphenicol

b. Novalgin d. thymol

3. Which of the following is an antibiotic drug?

a. Aspirin  c. Novalgin

b. Valium  d. Chloramphenicol

4. Aspirin is

a. Analgesic  c. Antibiotic

b. Antipyretic  d. Both a and b.

5. 1 % solution of phenol is

a. Antipyretic c. Anti histamine

b. Disinfectant d. Analgesic

6. The use of chemicals for the treatment of diseases is called as

a. Chemotherapy c. Physiotherapy

b. Homeotherapy d. Physiotherapy

7. Tranquilizers are substances used for the treatment of

a. Mental diseases c. Malaria

b. Physical disease d. Cancer

8. Acetyl salicylic acid acts as

a. Antacid c. Antipyretic

b. Antibiotic d. Antiseptic

9. Dettol consists of

a. Xylenol + terpineol

b. Chloroxylenol + terpineol

c. Cresol + ethanol

d. None of the above

10. A broad spectrum antibiotic is

a. Paracetamol c. Penicillin

b. Aspirin d. Chloramphenicol

11. Salbutamol is

a. Antihistamine c. Tranquilizer

b. Bronchodilator d. Antacid

12. Antacids contain

a. Strong acids c. Weak acids

b. Strong bases d. Weak bases

Answer :

1 –2- 3- 4- d

5- 6 –7- 8- c

9- 10- 11-12 – d