if your brother was specifically prescribed a diuretic by one of his physicians who are treating his lung cancer then yes. he should take it. each person on chemotherapy is unique. often taking different types and dosages of chemotherapeutic agents and not every person would need a diuretic. your brother appears that he does. i wish your brother and family the very best on his treatment.
should you take a diuretic when taking chemo. my brother has lung cancer and they have prescribed a diuretic for swelling and fluid retention in his legs. should he be taking a diuretic while on chemo