Drugs are classified on the basis of their chemical properties and modes of action.
Analgesics (painkillers) reduce pain e.g. aspirin, paracetamol etc.
Antibiotics inhibit or kill bacteria and treat bacterial infections e.g. tetracycline, cephalosporin etc.
Sedatives induce sedation by reducing irritability or excitement e.g. diazepam.
Vaccines are used to develop immunity against viral and bacterial infections e.g. vaccines against small pox, whooping cough, hepatitis B etc.
