磺胺类全部磺胺类均能早期抑制细菌叶酸的形成。一般认为,磺胺衍生物的抗菌效果彼此差异不大,但由于有广泛的交叉抗药性,当到达有效浓度时,抗菌作用就不同了。例如衍生物磺胺嘧啶(SD),在北美洲被用来治疗脑膜炎球菌感染及带菌者,疗效显著,大约达到英国常用的磺胺二甲嘧啶(SM_2)的 Sulfonamides all sulfa can early inhibit bacterial folic acid formation. It is generally believed that the antimicrobial effects of sulfonamide derivatives are not significantly different from one another, but because of their broad cross-resistance, the antibacterial effect is different when effective concentrations are reached. For example, the derivative sulfadiazine (SD), which is used to treat meningococcal infections and carriers in North America, has a significant effect, reaching approximately the level of sulfamethazine (SM 2) commonly used in the United Kingdom