Which sulfonamide is primarily used as a topical treatment?

Sulfacetamide is primarily used as a topical treatment because it is formulated as an ophthalmic and dermatological preparation. Its ability to target local infections, particularly those affecting the eyes and skin, makes it suitable for topical applications. Sulfacetamide works by inhibiting bacterial folic acid synthesis, which is essential for bacterial growth and reproduction, effectively treating bacterial conjunctivitis and other skin infections.

In contrast, the other sulfonamides listed are generally administered systemically rather than topically. For instance, sulfamethoxazole is often used in combination with trimethoprim for systemic infections, while sulfadiazine is typically used for serious infections like those caused by Streptococcus or for treating burns. Sulfisoxazole is also more frequently used for systemic infections, particularly in children for otitis media. This distinction in application routes solidifies sulfacetamide’s role as the sulfonamide specifically indicated for topical use.