RESUMO
The effects of four commonly prescribed diuretics on serum potassium were assessed. One hundred sixteen elderly clinic patients, independently living, (mean age 74.3 years, range 60 to 99 years) were taking hydrochlorothiazide (HCTZ) (n = 40; mean daily dose, 53.9 mg), a combination of hydrochlorothiazide-triamterene (HCTZ-TMTR) (n = 38; mean daily dose, 1.28 capsules), furosemide (n = 20; mean daily dose, 38.0 mg), or chlorthalidone (n = 18; mean daily dose, 55.6 mg). Patients did not take more than one diuretic. No patients received potassium supplementation or had diseases affecting potassium balance. The study design was a nonblinded, noncrossover retrospective chart audit with chi-square analysis. All patients were counseled about reducing excessive sodium intake and using potassium-rich foods and salt substitutes, although compliance concerning these dietary factors was not assessed. Even though some comparisons of diuretics showed statistical significance, these differences probably are not clinically significant because all serum potassium values were above 3.0 mEq/L and no patient was symptomatic. This study supports the use of HCTZ as an initial antihypertensive diuretic; it is as efficacious as the other diuretics in this study, is less expensive, and usually does not cause clinically significant hypokalemia more often than do the other diuretics.