Renal Effects of Diazoxide and Frusemide and Interrelattonships

Abstract

The successful long-term control of diazoxide-induced Na retention in 52 hypertensive patients (mean creatinine clearance (C_cr) 38 ± 30.6 ml/min, range 1–123 ml/min) by the use of potent diuretics is reported. The mean duration of follow-up was 26.2± 14.4 months with a range of 3–52 months. The mean daily dose of frusemide was 344 mg (range 40–1000 mg). The mean daily dose of ethacrynic acid was 318 mg (range 100–800 mg). Rashes necessitating change of therapy were attributed to frusemide in seven patients.

Diuretic dosage, corrected for patient Na intake, was independent of diazoxide serum levels (S.L.) below 100 mg/litre but was inversely correlated with C_CI (^rdiuretic, _NaC_CI(S.L. constant)= −0.33 2P<0.05).

Concordant estimates of patient Na intake were obtained and the estimated mean daily Na intake of 121.2 ±62.1 mEq falls within the normal range. The eight patients with estimated mean Na intakes < 50 mEq/day (mean: 35 mEq/day) had a mean Ccr of 11.04 ± 5.98 ml/min whilst the 31 patients with estimated mean Na intakes > 100 mEqjday (mean: 158.9 mEqjday) had a mean C_cr of 48.92 ± 5.05 ml/min. This discrepancy was interpreted as due to a limitation in the ability to correct diazoxide-induced Na retention in patients with severe renal failure. In practice such patients are kept in balance by the use of more than one diuretic combined with a restricted Na intake.