OPEN AND COMPARATIVE TREATMENT STUDIES WITH TETROXOPRIM-SULFADIAZINE COMBINATIONS IN URINARY INFECTIONS (1975-1979)

Tetroxoprim/sulphadiazine (TXP/SDZ) combinations were used to treat hospitalized patients with sensitive urinary infections. After an open design pilot study which demonstrated promising efficacy, good tolerability and negligible toxicity, two comparative trials against trimethoprim/sulphamethoxazole (co- trimoxazole; TMP/SMZ) were done using a randomized allocation design. After loading doses, TXP/SMZ was given at 50 mg/250 mg 12-hourly in the first comparative study, and at 100 mg/250 mg 12-hourly in the second. TMP/SMZ was used at 160 mg/800 mg 12-hourly throughout. As judged by the eradication of the original infecting pathogen the two combinations had similar overall cure rates (TXP/SDZ 71% of 76 patients, TMP/SMZ 78% of 69 patients, at 2 weeks follow-up). These rates were considered to be satisfactory in this difficult group of patients. TXP/SDZ showed a trend towards being better tolerated than TMP/SMZ, although this was not significant. The toxicity of both combinations was negligible. A study of the pharmacokinetics of TXP/SDZ showed that, overall, both drugs were absorbed as completely as in previous studies using fasting volunteers. Satisfactory concentrations for therapy were achieved in blood and urine, the steady state being achieved in blood on the first day by the use of the loading dose. During one week’s therapy of TXP 100 mg/SDZ 250 mg 12-hourly there was no accumulation of either drug in the blood. © 1979 Oxford University Press.