The Sulphonamides, antibacterial agentsAlthough the sulphonamides have been superseded in many countries by the antibiotics, their sphere of usefulness has now been extended by the introduction of co-trimoxazole, a sulphonamide combined with trimethoprim. The sulphonamides have the merit of being inexpensive but the disadvantage of having a wide range of potential dangers.
Sulphadimidine. This is the sulphonamide of choice for general purposes as it combines effectiveness with low toxicity. Sulphadimidine is rapidly absorbed and relatively slowly excreted in the urine in a fairly soluble form. An effective concentration in the blood can usually be maintained by administration every four to six hours. Sodium salts are available for intravenous and intramuscular administration if the patient is vomiting or comatose as may occur in meningococcal meningitis. In the treatment of this condition sulphadiazine may be even more effective because it attains higher concentrations in the cerebrospinal fluid. In recent years some serotypes of the meningococcus have acquired a partial resistance to sulphonamides and in these circumstances benzylpenicillin should be prescribed. It is advisable to use sulphadiazine or oral penicillin as a prophylactic measure if meningococcal meningitis occurs in a closed community