THE EFFECT OF COMBINED THERAPY WITH CAPTOPRIL, FUROSEMIDE, AND A SODIUM-RESTRICTED DIET ON SERUM ELECTROLYTE CONCENTRATIONS AND RENAL-FUNCTION IN NORMAL DOGS AND DOGS WITH CONGESTIVE-HEART-FAILURE

Captopril, furosemide, and a sodium-restricted diet were administered to 6 normal dogs and 10 dogs with congestive heart failure. Serum elec trolyte concentrations and renal function were monitored in both group s. In the normal dogs, no clinically meaningful changes in serum elect rolyte, urea nitrogen, or creatinine concentrations developed during t herapy with a sodium-restricted diet and 4 weeks each of furosemide al one, captopril alone, or furosemide plus captopril. Three of 6 normal dogs on furosemide and a sodium-restricted diet had at least one serum potassium concentration above the reference range during the 4 weeks of observation. One normal dog on captopril, furosemide, and a sodium- restricted diet developed azotemia, and 2 dogs had serum potassium con centrations above the reference range during the 4 weeks of observatio n. Ten dogs with congestive heart failure were treated with captopril, furosemide, a sodium-restricted diet, and digoxin. Etiopathogenesis o f the heart failure included valvular insufficiency (n = 6), dilated c ardiomyopathy (n - 3), and dilated cardiomyopathy and dirofilariasis ( n = 1). Serum electrolyte concentrations and renal function were monit ored for 5 consecutive weeks in 7 of the 10 dogs and for 17 weeks or l onger in 6. Two dogs were euthanized after 4 weeks because of acute de compensation of heart failure, and one dog developed severe azotemia a nd uremia. Six of 1 0 dogs with congestive heart failure had at least one serum potassium concentration above the reference range sometime d uring the 5 weeks of observation, although the changes in the mean ser um potassium concentrations were not statistically significant. Four o f 10 dogs with congestive heart failure developed azotemia sometime du ring the 5 weeks of observation.