Extensive experience with the sulfonamide drugs in clinics throughout the United States has established sulfadiazine as the drug of choice in the treatment of pneumococcic pneumonia because of its greater efficacy and lower toxicity.1 Hence it is important to establish its optimum dose in order that it may be used with maximum effectiveness.
The initial dose of sulfadiazine usually advocated is 4 or 5 Gm.2 However, it varies from 23 to 711 Gm. A maintenance dose of 1 Gm. every four hours is usually given,4 although 1 Gm.5 or 2 Gm.1i every six hours have also been used. It has been demonstrated1i that, since sulfadiazine is excreted slowly, a proportionately higher dose given every six hours is as effective in maintaining adequate blood concentrations as is a four hourly dose.
Early in the use of sulfadiazine, its administration by the intravenous route was reserved for critically ill