Furosemide is a loop diuretic which increases the secretion of both sodium and potassium in the urine. The most common side effect of loop diuretics is hypokalemia. The normal potassium levels is 3.5 to 6.0 mEq/L, that's why hypokalemia is considered in this patient. Assessment findings of muscle weakness (a symptom of rhabdomyolysis) and a weak, irregular pulse (symptom of cardiac arrhythmias) will confirm electrolyte imbalance. Other manifestations include renal abnormalities and glucose intolerance.