Hypokalemia is seen with -

Furosemide also can lead to gout caused by hyperuricemia. Hyperglycemia is also a common side effect. The tendency, as for all loop diuretics, to cause low serum potassium concentration (hypokalemia) has given rise to combination products, either with potassium or with the potassium-sparing diuretic amiloride (Co-amilofruse). Other electrolyte abnormalities that can result from furosemide use include hyponatremia, hypochloremia, hypomagnesemia, and hypocalcemia. In the treatment of hea failure, many studies have shown that the long-term use of furosemide can cause varying degrees of thiamine deficiency, so thiamine supplementation is also suggested. Although disputed, it is considered ototoxic: "usually with large intravenous doses and rapid administration and in renal impairment". Other precautions include: nephrotoxicity, sulfonamide (sulfa) allergy, and increases free thyroid hormone effects with large doses Ref Davidson 23rd edition pg 365