Chemistry in Everyday Life

Drugs – Introduction

Chemical compounds used for the treatment of diseases are called drugs or medicines.

Types of Drugs

1. Antipyretics

• Used to bring down body temperature in case of fever
• Examples: Paracetamol, Aspirin

2. Analgesics

• Used to relieve pain
• Some have antipyretic properties
• Examples: Aspirin, Ibuprofen, Analgin

Structure of Aspirin

Aspirin: 2-Acetoxy benzoic acid

3. Tranquilisers

• Used for treatment of stress and mental disorders
• Induce a sense of well-being
• Also called psychotherapeutic drugs
• Hypnotic tranquilisers (sleep-inducing): Barbiturates

4. Antiseptics & Disinfectants

• Antiseptics: Kill or prevent growth of microorganisms and are safe for living tissues
• Example: Dettol (mixture of chloroxylenol and terpineol)

5. Anti-fertility Drugs

• Used to prevent pregnancy
• Contain synthetic estrogen and progesterone derivatives
• Control ovulation and menstrual cycle
• Mifepristone: Synthetic steroid used as “morning after pill”

6. Antihistamines (Anti-allergic Drugs)

• Counteract the effects of histamine released during allergic reactions
• Used in skin rashes, conjunctivitis, rhinitis, sneezing, itching
• Examples: Diphenylhydramine, Chlorpheniramine, Promethazine

7. Antibiotics

• Substances that inhibit growth or destroy microorganisms at low concentration
• Act by interfering with metabolic processes of microbes

Bactericidal vs Bacteriostatic Antibiotics

• Bactericidal: Penicillin, Aminoglycosides, Ofloxacin
• Bacteriostatic: Erythromycin, Tetracycline, Chloramphenicol

8. Sulpha Drugs

• Act against disease-causing microorganisms
• Examples: Sulphanilamide, Sulphadiazine, Sulphaguanidine

9. Antacids

• Neutralise excess acid and adjust stomach pH
• Used to treat acid gastritis
• Examples:
  • Magnesium hydroxide
  • Magnesium carbonate
  • Magnesium trisilicate
  • Aluminium hydroxide gel
  • Sodium bicarbonate
  • Aluminium phosphate
  • Omeprazole, Lansoprazole

Dyes

A dye is a coloured substance that can be applied to a substrate to impart colour.

Substrates

• Fibre, paper, leather, hair, fur
• Plastic, wax, foodstuff

Earliest Known Dyes

• Indigo – blue dye
• Alizarin – red dye

Classification of Dyes Based on Constitution

• Azo dyes (–N=N–): Aniline yellow, Orange-I, Methyl orange, Congo red
• Nitro dyes (–NO₂): Martius yellow
• Phthalein dyes: Phenolphthalein
• Triphenylmethane dyes: Magenta, Malachite green
• Indigoid dyes: Indigo
• Anthraquinoid dyes: Alizarin