Bumetanide, sold under the brand name Bumex among others, is a medication used to treat swelling and high blood pressure. This includes swelling as a result of heart failure, liver failure, or kidney problems. It may work for swelling when other medications have not. For high blood pressure it is not a preferred treatment. It is taken by mouth, or by injection into a vein or muscle. Effects generally begin within an hour and lasts for about six hours.

Common side effects include dizziness, low blood pressure, low blood potassium, muscle cramps, and kidney problems. Other serious side effects may include hearing loss and low blood platelets. Blood tests are recommended regularly for those on treatment. Safety during pregnancy and breastfeeding is unclear. Bumetanide is a loop diuretic and works by decreasing the reabsorption of sodium by the kidneys.

Bumetanide was patented in 1968 and came into medical use in 1972. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. In 2020, it was the 270th most commonly prescribed medication in the United States, with more than 1 million prescriptions.