Severe electrolyte disturbances associated with metolazone and furosemide

In two patients with severe hypertension and moderately severe renal insufficiency, metolazone and furosemide were used in combination with propranolol, methyldopa, and hydralazine to augment control of blood pressure. This combination of diuretics also was used in five patients with refractory congestive heart failure. The patients developed severe electrolyte disturbances with a general pattern of hyponatremia. disproportionate hypochloremia, alkalosis, and phyokalemia. These abnormalities were transient in the patients with severe hypertension and moderately severe renal insufficiency. Effective long-term control of blood pressure was obtained. In the patients with heart failure, edema persisted. Due to the severity of the electrolyte derangements, metolazone and furosemide were discontinued. Because of potential untoward effects, this combination of diuretics should be used with caution.