An 83-year-old woman has chronic congestive heart failure (CHF) due to grade IV left ventricular function (ejection fraction <20%). She requires 80 mg/day of furosemide as part of her treatment. Which of the following metabolic abnormalities is most likely to be seen while she is taking this medication?

In addition to dehydration, hypokalemia, hypochloremia, and alkalosis also result from excessive use of furosemide. Loop diuretics such as furosemide act primarily to inhibit electrolyte reabsorption in the thick ascending limb of the loop of Henle. The degree of diuresis is greater than in other classes of diuretics.