On the basis of molecular targets

Classification by molecular target groups drugs by the specific biomolecule they physically bind to inside the body, and is considered by medicinal chemists to be the most useful and mechanistically informative of the four schemes, because it points directly at the chemical event responsible for the drug's action.

Drugs interact with large biological molecules - carbohydrates, lipids, proteins and nucleic acids - which are collectively referred to as target molecules or drug targets. Two structurally related drugs very often act on the same target molecule by essentially the same chemical mechanism, which is why this classifi …