Antimetabolites are drugs that exploit the metabolic difference between normal cells and pathological cells. The antimetabolite concept is supported by: All of the other options are correct/ the effectiveness of sulphanilamide drugs which inhibits the synthesis of folic acid in human liver cells. the synthesis of folic acid analogues with reduced affinity for dihydrofolate reductase. the mechanism of action of the folic acid analogue methotrexate as a competitive inhibitor of the enzyme dihydrofolate reductase.