Development status: Approved, off-patent, discontinued in most countries as monotherapy

Gram-positive activity

Gram-negative activity

Mechanism of Action/Target pathogen: Sulphonamides are structural analogues of p-aminobenzoic acid and act as competitive inhibitors (and alternate substrates) of dihydropteroate synthase (DHPS) to block the synthesis of folic acid. Primarily bacteriostatic; rapid emergence of resistance.

Additional information: Synthetic sufanilamide derivative; intermediate-acting (8-12 hours). Mostly used in fixed combination with trimethoprim (synergistic combination) for treatment and prophylaxis (oral and iv).