Lasix Side Effects

Generic Name: furosemide

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

Some side effects of Lasix may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to furosemide: oral solution, oral tablet

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

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

Cardiovascular

Volume depletion may predispose some patients to deep venous thrombosis.

In a study of patients with congestive heart failure (CHF) due to myocardial infarction, furosemide (the active ingredient contained in Lasix) has been shown to decrease left ventricular end diastolic pressure and decrease peripheral vascular resistance before a significant increase in urine output or decrease in arterial blood pressure is observed.

However, in patients with advanced, chronic CHF, the IV administration of furosemide may result in an acute vasoconstrictor response associated with an acute increase in vasoconstrictive hormones, such as norepinephrine, renin, and arginine vasopressin (AVP).

After central venous catheter administration of furosemide 125 mg, 3rd degree AV heart block was observed in a very ill patient (one case report). Because no other etiology was found, it was believed that the relatively high pH of furosemide and/or the rapid rate of administration caused the arrhythmia.

Furosemide may increase cholesterol and triglyceride serum levels.

Cardiovascular side effects have commonly included intravascular volume depletion and hypotension. Signs and symptoms of furosemide-induced volume depletion have included thirst, muscle cramps, weakness, dizziness, lightheadedness, syncope, tachycardia, palpitations, and dry skin. In addition, these signs and symptoms have often been associated with a hypochloremic metabolic alkalosis and increased serum BUN and creatinine.

Metabolic

Hyperuricemia is usually a benign side effect, but may be important in some patients with a history of gout.

Although less so than with thiazide diuretics, furosemide (the active ingredient contained in Lasix) may induce a relative glucose intolerance, which may be important in some patients, such as diabetics.

Rare instances of hypocalcemia have been reported in patients with latent hypoparathyroidism, in which case both calcium and magnesium replacement may be helpful.

Metabolic abnormalities may be more likely and severe in patients with liver disease. If a patient has severe liver disease, frequent monitoring of the patient's electrolytes is recommended.

Calcium balance appears to remain neutral during treatment with a loop diuretic (i.e., furosemide, bumetanide). Although loop diuretics cause an increase in renal calcium excretion, this appears to be compensated for by a parathyroid-dependent increase in 1,25-dihydroxyvitamin D levels, which increases intestinal calcium absorption. Bone metabolism does not appear to be significantly affected by loop diuretics.

Metabolic side effects including hypokalemia, hypomagnesemia, and an increase in serum uric acid, have been relatively common especially with higher doses. Although less common than with thiazide diuretics, mild hyperlipidemia and hypercholesterolemia have been associated with the use of furosemide. A single study suggests that chronic furosemide therapy is associated with clinically significant thiamine deficiency via urinary thiamine loss. This may be important in patients with congestive heart failure since thiamine deficiency may impair cardiac performance.

Furosemide has been reported to displace thyroxine (T4) from protein-binding sites. When administered in large intravenous doses (above 80 mg), a transient increase in serum free T4 concentrations and decrease in serum total T4 concentrations have been reported.

Hypersensitivity

Hypersensitivity reactions to furosemide (the active ingredient contained in Lasix) have been uncommon. Rashes, fever, malaise, interstitial nephritis, and eosinophilia have been reported. Severe anaphylactic or anaphylactoid reactions (e.g., with shock) have been reported.

Furosemide contains a sulfur moiety, and may induce an allergic reaction in some patients with a history of sulfa sensitivity.

Rare cases of interstitial nephritis and hypersensitivity angiitis associated with furosemide have been reported.

Nervous system

The doses of furosemide (the active ingredient contained in Lasix) in cases of tinnitus, vertigo, or deafness ranged from 0.24 grams IV given over 40 minutes to 3 grams IV in divided doses over 9 hours and 2 grams IV in a single dose. It is recommended that infusion rates not exceed 4 mg/min to minimize the risk of ototoxicity.

Ototoxicity may be more likely and more severe due in patients with renal insufficiency.

Nervous system side effects have included headaches and dizziness. Cases of tinnitus and reversible or irreversible hearing impairment and deafness have been reported.

Gastrointestinal

Gastrointestinal side effects have included hepatic encephalopathy in patients with hepatocellular insufficiency, pancreatitis, jaundice (intrahepatic cholestatic jaundice), anorexia, oral and gastric irritation, cramping, diarrhea, constipation, nausea, and vomiting.

Hepatic

Cholestatic jaundice may be important in patients with liver disease.

Hepatic side effects have included rare cases of cholestatic jaundice and increased liver enzymes.

Hematologic

Hematologic side effects have included eosinophilia. Thrombocytopenia, aplastic anemia, and leukopenia have been very rare.

Dermatologic

One patient experienced acute generalized exanthematic pustulosis a few hours after receiving intravenous furosemide (the active ingredient contained in Lasix)

Dermatologic reactions, such as bullous pemphigoid have been reported in rare cases. Exfoliative dermatitis, erythema multiforme, purpura, photosensitivity, urticaria, rash, Stevens-Johnson Syndrome, toxic epidermal necrolysis, and pruritus have also been reported.

At least two cases of Sweet syndrome related to use of furosemide have been reported. In one case, Sweet syndrome was characterized by low-grade fever, tender, papular, erythematous, nonpruritic skin lesions on the arms and thighs, and redness in the eyes with photophobia. Papuloerythroderma of Ofuji has also been associated with furosemide use.

Dermatologic side effects reported postmarketing have included drug rash with eosinophilia and systemic symptoms and acute generalized exanthematous pustulosis.

Renal

Renal side effects have included nephrocalcinosis/nephrolithiasis in premature infants treated with furosemide (the active ingredient contained in Lasix) therefore renal function should be monitored and renal ultrasonography performed.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.

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