Hello, May I presume that your doctor had prescribed you Furosemide and spironolactone for a condition in which you were accumulating water in the body. It is better that you take them both together as Spironolactone prevents the loss of Potassium which Furosemide causes and there is less chance of an electrolyte abnormality. These medicines are to be taken only if they were prescribed by a doctor who had examined you. Hope I have answered your query and if you have any other, I shall be happy to be of help. Wish you good health Dr. Noble Zachariah M.D.