Get emergency medical help if you have signs of an allergic reaction to Lasix: (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning in your eyes, skin pain, red or purple skin rash that spreads and causes blistering and peeling).
Call your doctor at once if you have:
ringing in your ears, hearing loss;
easy bruising, unusual bleeding;
sudden weakness or ill feeling, fever, chills;
painful or difficult urination;
numbness, tingling, or burning pain;
a light-headed feeling, like you might pass out;
high blood sugar - increased thirst, increased urination, dry mouth, fruity breath odor;
signs of liver or pancreas problems - loss of appetite, upper stomach pain (that may spread to your back), nausea or vomiting, dark urine, jaundice (yellowing of the skin or eyes);
kidney problems - little or no urination, swelling in your feet or ankles, feeling tired or short of breath; or
signs of an electrolyte imbalance - dry mouth, increased thirst, mood changes, weakness, drowsiness, lack of energy, muscle pain, fast heartbeats, feeling restless, nausea, vomiting.
Common Lasix side effects may include:
diarrhea, constipation;
numbness or tingling;
headache, dizziness; or
blurred vision.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Lasix side effects (more detail)
