Title: Drugs - Sulfa
Headings: 

Content: Drugs - Sulfa
















Antibacterial Agents  - Sulfa Drugs
Sulfonamides or Sulfa Drugs as Antimetabolites: The sulfonamides are synthetic antimicrobial agents with a  wide spectrum encompassing most gram-positive and many gram-negative  organisms. These drugs were the first efficient treatment to  be employed systematically for the prevention and cure of bacterial  infections. Their use introduced and substantiated the concept of metabolic  antagonism. Sulfonamides, as antimetabolites, compete with para-aminobenzoic  acid (PABA) for incorporation into folic acid. The action of  sulfonamides illustrates the principle of selective toxicity  where some difference between mammal cells and bacterial cells  is exploited. All cells require folic acid for growth. Folic  acid (as a vitamin is in food) diffuses or is transported into  human cells. However, folic acid cannot cross bacterial cell  walls by diffusion or active transport. For this reason bacteria  must synthesize folic acid from p-aminobenzoic acid.