Note: This document contains side effect information about furosemide. Some dosage forms listed on this page may not apply to the brand name Lasix.

Applies to furosemide: oral solution, oral tablet. Other dosage forms:

• injection solution

Serious side effects of Lasix

Along with its needed effects, furosemide (the active ingredient contained in Lasix) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking furosemide:

Rare

• Chest pain
• chills
• cough or hoarseness
• fever
• general feeling of tiredness or weakness
• headache
• lower back or side pain
• painful or difficult urination
• shortness of breath
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• swollen or painful glands
• tightness in the chest
• unusual bleeding or bruising
• unusual tiredness or weakness
• wheezing

Incidence not known

• Back or leg pains
• black, tarry stools
• bleeding gums
• blistering, peeling, or loosening of the skin
• bloating
• blood in the urine or stools
• blurred vision
• burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
• changes in skin color, pain, tenderness, or swelling of the foot or leg
• clay-colored stools
• cloudy urine
• cold sweats
• confusion
• constipation
• continuing ringing or buzzing or other unexplained noise in the ears
• coughing up blood
• cracks in the skin
• darkened urine
• diarrhea
• difficulty breathing
• dizziness, faintness, or lightheadedness when getting up from a lying or sitting position
• dry mouth
• fast heartbeat
• flushed, dry skin
• fruit-like breath odor
• greatly decreased frequency of urination or amount of urine
• hearing loss
• increased hunger
• increased thirst
• indigestion
• itching
• loss of appetite
• nausea or vomiting
• nosebleeds
• pain in the joints or muscles
• pains in the stomach, side, or abdomen, possibly radiating to the back
• pale skin
• pinpoint red spots on the skin
• red, irritated eyes
• red, swollen skin
• skin rash
• spots on your skin resembling a blister or pimple
• sweating
• swelling of the feet or lower legs
• trouble breathing with exertion
• unusual weight loss
• vomiting of blood
• yellow eyes or skin

Get emergency help immediately if any of the following symptoms of overdose occur while taking furosemide:

Symptoms of overdose

• Decreased urination
• drowsiness
• increase in heart rate
• irregular heartbeat
• irritability
• mood changes
• muscle cramps
• numbness, tingling, pain, or weakness in the hands, feet, or lips
• rapid breathing
• seizures
• sunken eyes
• thirst
• trembling
• weak pulse
• weakness and heaviness of the legs
• wrinkled skin

Other side effects of Lasix

Some side effects of furosemide may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known

• Feeling of constant movement of self or surroundings
• hives or welts
• increased sensitivity of the skin to sunlight
• muscle spasm
• redness or other discoloration of the skin
• restlessness
• sensation of spinning
• severe sunburn
• weakness

For Healthcare Professionals

Applies to furosemide: compounding powder, injectable solution, intravenous solution, oral liquid, oral solution, oral tablet, subcutaneous kit.

Metabolic

Common (1% to 10%): Hyponatremia, hypochloremia, hypokalemia, blood cholesterol increased, blood uric acid increased, gout

Uncommon (0.1% to 1%): Thirst, glucose tolerance decreased

Rare (0.01% to 0.1%): Anorexia, serum triglycerides increased

Frequency not reported: Hyperglycemia, diabetes mellitus, hyperuricemia, metabolic alkalosis, hypocalcemia, hypomagnesemia, hypovolemia, dehydration, tetany, serum potassium decreased, Pseudo-Bartter syndrome, electrolyte disturbances, serum calcium decreased^[Ref]

Hematologic

Common (1% to 10%): Hemoconcentration

Uncommon (0.1% to 1%): Thrombocytopenia

Rare (0.01% to 0.1%): Eosinophilia, leukopenia, bone marrow depression

Very rare (less than 0.01%): Hemolytic anemia, aplastic anemia, agranulocytosis

Frequency not reported: Anemia, thrombophilia^[Ref]

Genitourinary

Common (1% to 10%): Urine volume increased

Frequency not reported: Glycosuria, bladder spasm, urinary retention, urinary incontinence^[Ref]

Dermatologic

Uncommon (0.1% to 1%): Pruritus, bullous exanthema, rash, urticaria, purpura, erythema multiforme, exfoliative dermatitis, photosensitivity

Rare (less than 0.1%): Lyell's syndrome and Stevens-Johnson syndrome, acute generalized exanthematous pustulosis, drug rash with eosinophilia and systemic symptoms

Frequency not reported: Toxic epidermal necrolysis, bullous pemphigoid, sweating^[Ref]

Gastrointestinal

Uncommon (0.1% to 1%): Dry mouth, nausea, bowel motility disturbances, vomiting, diarrhea, constipation

Rare (less than 0.1%): Gastric distress, acute pancreatitis

Frequency not reported: Pancreatitis, oral and gastric irritation, cramping^[Ref]

Renal

Uncommon (0.1% to 1%): Blood creatinine increased, urea increased

Rare (less than 0.1%): Interstitial nephritis, acute renal failure

Frequency not reported: Nephrocalcinosis in premature infants, nephrolithiasis in premature infants, GFR decreased, tubulointerstitial nephritis^[Ref]

Other

Uncommon (0.1% to 1%): Deafness, fatigue

Rare (less than 0.1%): Sensation of pressure in the head, dysacusis, asthenia, fever, febrile conditions, malaise

Frequency not reported: Weakness, sudden death, hearing disorders, hearing loss, paradoxical swelling^[Ref]

Cardiovascular

Uncommon (0.1% to 1%): Cardiac arrhythmia

Rare (less than 0.1%): Vasculitis

Frequency not reported: Systemic vasculitis, necrotizing angiitis, orthostatic hypotension, thrombophlebitis, acute hypotension, circulatory collapse, persistent patent ductus arteriosus during the first few weeks of life in premature infants with respiratory distress syndrome, blood pressure decreased, shock, hypotension, thrombosis, orthostatic blood pressure decreased^[Ref]

Ocular

Uncommon (0.1% to 1%): Visual disturbance

Rare (less than 0.1%): Myopia aggravated, blurred vision

Frequency not reported: Blurred vision, xanthopsia^[Ref]

Nervous system

Rare (0.01% to 0.1%): Paresthesia, vertigo, dizziness, sleepiness, tinnitus, hyperosmolar coma

Frequency not reported: Hepatic encephalopathy, headache, fainting and loss of consciousness, drowsiness, lethargy, sweet taste^[Ref]

Musculoskeletal

Rare (less than 0.1%): Lupus erythematosus activation or exacerbation, leg muscle cramps, chronic arthritis

Frequency not reported: Muscle spasm, rhabdomyolysis^[Ref]

Immunologic

Rare (less than 0.1%): Severe anaphylactic or anaphylactoid reactions

Frequency not reported: Allergic reactions^[Ref]

Hepatic

Very rare (less than 0.01%): Jaundice, hepatic ischemia, liver enzymes increased

Frequency not reported: Abnormal hepatic function, cholestasis, bile flow increased, biliary tree distended^[Ref]

Psychiatric

Frequency not reported: Restlessness, psychiatric disorder, apathy^[Ref]