Sulfonamides

Definition

Sulfonamides are a class of antimicrobial drugs that inhibit the synthesis of folic acid in bacteria, thus preventing their growth. They are often used to treat bacterial infections such as urinary tract infections and bronchitis.

5 Must Know Facts For Your Next Test

1. Sulfonamides act as competitive inhibitors of the enzyme dihydropteroate synthase.
2. They were among the first antibiotics discovered and widely used before the advent of penicillin.
3. Sulfonamides are bacteriostatic rather than bactericidal, meaning they inhibit bacterial growth but do not kill bacteria outright.
4. Resistance to sulfonamides can occur through mutations in the target enzyme or increased production of para-aminobenzoic acid (PABA).
5. Common side effects include allergic reactions, such as skin rashes, and gastrointestinal disturbances.

Review Questions

• What is the primary mechanism by which sulfonamides inhibit bacterial growth?
• Why are sulfonamides considered bacteriostatic rather than bactericidal?
• How can bacteria develop resistance to sulfonamides?

Related terms

Dihydropteroate Synthase:

An enzyme targeted by sulfonamides to inhibit folic acid synthesis in bacteria.

Bacteriostatic:

Describes a drug that inhibits the growth and reproduction of bacteria without killing them.

Para-aminobenzoic Acid (PABA): A substrate for folic acid synthesis in bacteria that competes with sulfonamides.