Additive effects of a sodium chloride restricted diet and furosemide administration in healthy dogs

Objective-To determine the effects of a low or high sodium (Na) diet with o r without furosemide administration on plasma electrolyte concentrations an d the renin-angiotensin-aldosterone system in healthy dogs. Animals-20 healthy adult dogs. Procedure-Dogs were randomly allotted to 4 groups of 5 dogs each as follows : dogs fed a low Na diet (0.08% Na and 0.8% chloride [Cl] on a dry matter [ DM] basis); dogs fed a low Na diet with added NaCl (1.0% Na and 2.2% Cl on a DM basis); dogs fed a low Na diet and treated with furosemide (2 mg/kg of body weight, PO, q 12 h); and dogs fed a low Na diet with added NaCl and t reated with furosemide. Plasma electrolyte concentrations were measured on days 0, 21, and 35. Plasma renin activity and aldosterone concentration wer e analyzed by use of radioimmunoassays on days 0, 21, 35, and 53. Results-Furosemide treatment significantly decreased plasma CI concentratio n and significantly increased plasma renin activity and aldosterone concent ration. Dogs fed a low Na diet had significantly higher plasma renin activi ties and plasma aldosterone concentrations, A significant interaction betwe en a low Na diet and furosemide administration resulted in the lowest plasm a Cl concentrations, highest plasma renin activities, and highest plasma al dosterone concentrations. Conclusions and Clinical Relevance-In healthy dogs, feeding a low Na diet a nd administering furosemide resulted in an additive effect on plasma Cl con centration, renin activity, and aldosterone concentration, which may be an important consideration for treating dogs with cardiac disease.