MCB 3020 Chapter 8: Antifungal Drugs
Document Summary
Sulfonamides or sulfa drugs: structurally related to sulfanilamide, a paminobenzoic acid (paba) analog, paba used for the synthesis of folic acid and is made by many pathogens. Sulfa drugs are selectively toxic for these pathogens because they compete with paba for the active site of an enzyme involved in folic acid synthesis, resulting in a decline in folic acid concentration. Pathogen dies because folic acid is a precursor to purines and pyrimidines which are nucleic acid building blocks. Trimethoprim: synthetic antibiotic that also interferes with folic acid production, broad spectrum, can be combined with sulfa drugs to increase efficacy of treatment. Combination blocks two steps in folic acid pathway --- paba & dhf acid ie dhfr (dihydrofolate reductase: has a variety of side effects including abdominal pain and photosensitivity reactions. Nucleic acid synthesis inhibition: a variety of mechanisms. Block dna replication inhibition of dna polymerase inhibition of dna helicase.
