Sulfonamidi

Sulfonamidi, or sulfonamides, are a class of organic compounds that contain the sulfonamide functional group, typically represented as R-SO2-NR'R''. They include both antibiotic drugs and other therapeutic agents that share the same sulfonamide moiety.

Historically, sulfonamide antibiotics were among the first widely used antimicrobial agents, with practical impact in the 1930s. Their primary mechanism is to competitively inhibit bacterial dihydropteroate synthase, blocking the synthesis of folic acid and, consequently, DNA synthesis. This action is generally bacteriostatic, and effectiveness depends on the susceptibility of the organism. In many settings, sulfonamides are used in combination with trimethoprim to achieve a synergistic bactericidal effect (co-trimoxazole).

In addition to antibiotics, the sulfonamide group appears in other drugs with diverse uses. Examples include diuretics such as hydrochlorothiazide and certain loop diuretics, carbonic anhydrase inhibitors like acetazolamide, and anti-inflammatory and antiulcer agents such as sulfasalazine and sulfadiazine. These non-antibiotic sulfonamides can carry similar hypersensitivity risks in some patients.

Pharmacokinetics typically involve oral absorption with distribution throughout the body and renal excretion. Hydration is important to reduce the risk of crystalluria. Adverse effects range from mild hypersensitivity reactions to severe cutaneous adverse reactions; other possible effects include photosensitivity, hematologic abnormalities, nephrotoxicity, and, in newborns, kernicterus if used near term or in cases of early infancy. Allergy to sulfonamides is a consideration, and caution is advised in certain populations, including pregnant or nursing individuals and those with significant renal impairment.

Resistance to sulfonamides is well documented and can arise via altered target enzymes or reduced drug uptake, contributing to restricted use in some indications.