SN instructed in possible adverse reactions to Lasix, including dehydration, orthostatic hypotension, loss of potassium and other electrolytes, weakness, and fatigue. Lasix is used to reduce extra fluid in the body (edema) caused by conditions such as heart failure, liver disease, and kidney disease. This can lessen symptoms such as shortness of breath and swelling in your arms, legs, and abdomen. This drug is also used to treat high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. Lasix is a "water pill" (diuretic) that causes you to make more urine. This helps your body get rid of extra water and salt.