Lasix 40 mg tablets – furosemide for oedema (fluid retention) and high blood pressure

Lasix contains furosemide, a medicine from the group of diuretics (medicines that remove fluid) – a so-called loop diuretic. It helps the body remove excess water and salt via the urine that has accumulated around the heart, in the lungs, liver or kidneys, or in the tissues (oedema).

One tablet contains 40 mg furosemide. According to the SmPC, Lasix is indicated for conditions characterised by fluid retention and for mild to moderate hypertension, alone or as add-on therapy. In Serbia, Lasix 40 mg tablets in a pack of 12 have a valid authorisation; Lasix solution for injection and the 30-tablet pack no longer have a valid authorisation.

What is Lasix 40 mg used for and how should it be taken?

Key facts about the medicine

What is Lasix used for?

• removal of excess fluid from the body (oedema) in conditions with fluid retention – when water accumulates around the heart, in the lungs, liver or kidneys;
• mild to moderate hypertension (high blood pressure), alone or with other treatment (SmPC).
• If excess water is not removed, it can adversely affect the heart, blood vessels, lungs, kidneys or liver.

How is Lasix 40 mg taken?

• When: before a meal with enough water (a glass of water); unless the doctor says otherwise – in the morning.
• Adults and elderly (PIL): the usual dose is 2 tablets a day; elderly patients may start with lower doses – as advised by the doctor.
• According to the SmPC: the lowest dose sufficient for the desired effect is used, preferably once daily or every other day. The usual starting dose is 40 mg daily, then adjusted; in milder cases 20 mg daily or 40 mg every other day, in resistant oedema 80 mg or more. Higher doses are decided exclusively by the doctor.
• Children (PIL): the dose depends on body weight – 1–3 mg/kg daily, up to a maximum of 1 tablet (40 mg) daily, as prescribed.
• The doctor may request blood tests to check electrolytes.

Special patient groups

• Elderly (65+): furosemide is eliminated more slowly; caution is needed because of low blood pressure and dehydration. In elderly patients with dementia taking risperidone, the combination requires particular caution.
• Children: dose by body weight (see above). In newborns and premature infants, prolonged use of high doses requires kidney monitoring (ultrasound).
• Kidney or liver disease: serious disease requires caution; acute kidney failure, hepatic encephalopathy and severe liver failure with severe kidney failure are contraindications.

Contraindications – when the medicine must not be used

• allergy to furosemide, sulphonamides or any of the excipients;
• sudden loss of kidney function;
• serious difficulty or inability to pass urine (urinary tract obstruction);
• reduced body fluids (hypovolaemia, dehydration);
• excessively low blood potassium or sodium;
• hepatitis or severe liver damage, especially with severe kidney impairment (with or without dialysis);
• severe liver disease with impaired brain function (hepatic encephalopathy);
• according to the PIL the medicine must never be taken during pregnancy or with lithium.

Warnings and precautions

• Talk to your doctor if you have high blood sugar (pre-diabetes or diabetes), gout, serious liver or kidney disease, low blood pressure, low blood proteins, porphyria or systemic lupus erythematosus.
• Caution in people aged 65 and over and with other medicines that lower blood pressure.
• If your skin reacts excessively to sunlight or UV rays (photosensitivity), tell your doctor – treatment may need to be stopped.
• The tablets contain lactose – if you have an intolerance to some sugars, consult your doctor.
• The medicine may cause a positive result in anti-doping tests.

Interactions with other medicines, food and drink

• Do not combine: lithium (increased lithium levels and risk of overdose).
• ACE inhibitors (ramipril, enalapril, perindopril) and angiotensin II receptor antagonists (losartan, candesartan, irbesartan) – risk of a sudden drop in blood pressure and kidney damage; the doctor may change the dose;
• other blood pressure and heart medicines (alpha-blockers, nitrates), urological alpha-blockers (alfuzosin, doxazosin, prazosin, terazosin, tamsulosin), baclofen, neuroleptics, imipramine-type antidepressants – greater drop in blood pressure;
• medicines that can cause arrhythmias (torsades de pointes): antiarrhythmics (quinidine, amiodarone, sotalol), certain antipsychotics, i.v. erythromycin and spiramycin, levofloxacin, moxifloxacin, methadone, citalopram, escitalopram and others;
• digoxin (low potassium increases its toxicity), corticosteroids, amphotericin, long-term laxatives (bisacodyl, senna), high doses of salbutamol, terbutaline, salmeterol, formoterol – increased potassium loss;
• NSAIDs and acetylsalicylic acid (ibuprofen, ketoprofen, indometacin) – risk of kidney damage and weaker effect on blood pressure;
• aminoglycosides (gentamicin, amikacin, tobramycin), vancomycin, high-dose cephalosporins, cisplatin – hearing and kidney damage;
• metformin, theophylline, phenytoin (weakens the effect of furosemide), carbamazepine, ciclosporin, risperidone, amifostine, iodinated contrast media;
• potassium-sparing diuretics (amiloride, spironolactone, eplerenone, triamterene) – the doctor adjusts the dose.

Pregnancy and breast-feeding

• Pregnancy: Lasix must not be used during pregnancy; only in exceptional circumstances on medical advice, with careful monitoring of foetal development.
• Breast-feeding: do not breast-feed during treatment – small amounts pass into breast milk, and loop diuretics may reduce milk production.

Driving and using machines

• The SmPC does not state a specific effect on driving. However, a drop in blood pressure on standing, dizziness and fainting are possible side effects – if you experience them, do not drive or operate machinery.

Possible side effects

• Very common: reduced blood volume (hypovolaemia) with a drop in blood pressure on standing, dizziness and/or fainting; fluid and salt imbalance (dehydration); increased triglycerides and creatinine.
• Common: thickening of the blood, low potassium (hypokalaemia), low sodium (hyponatraemia), hepatic encephalopathy in severe liver disease, increased uric acid (gout attack), increased cholesterol, increased urine volume.
• Uncommon: skin reactions, itching, hives, bullous reactions, photosensitivity, erythema multiforme, purpura, nausea, hearing impairment (sometimes permanent), low platelet count, increased blood sugar.
• Rare: fever, eosinophilia, severe allergic (anaphylactic) reactions, vasculitis, tingling, vomiting and diarrhoea, interstitial nephritis, neutropenia, ringing in the ears.
• Very rare: liver or pancreas damage, agranulocytosis, bone marrow aplasia.
• Not known: urinary retention, Stevens-Johnson syndrome, TEN, AGEP, DRESS, lichenoid reactions, pseudo-Bartter syndrome, worsening of lupus, dizziness, fainting, headache, severe muscle disorders, thrombosis (especially in the elderly).

Overdose, missed dose and stopping treatment

• Overdose: contact a doctor or hospital immediately. Possible effects include confusion, inability to concentrate, apathy, dizziness, fainting (low blood pressure), irregular heartbeat, muscle weakness, cramps, blood clots and kidney problems.
• Missed dose: wait until the next dose is due; never take a double dose.
• Stopping treatment: continue treatment until your doctor tells you to stop.

Related information

For additional care and support with high blood pressure, see also the category Blood pressure devices – products in this category do not replace the medicine you have been prescribed.

Composition, pack and manufacturer

• Active substance: furosemide 40 mg per tablet.
• Excipients: maize starch; pregelatinised maize starch; lactose monohydrate; talc; colloidal anhydrous silica; magnesium stearate.
• Appearance: round, almost white tablets with a score line and the marking “DLI” on one side and the “Hoechst” logo on the other.
• Pack: carton with 1 PVC/Al blister of 12 tablets.
• Marketing authorisation holder: Amicus SRB d.o.o. Belgrade; manufacturer: Opella Healthcare International SAS, Compiègne, France.
• Authorisation number: 000457796 2023 of 17.07.2024 (renewal).

Storage

• Store below 25 °C, in the original package in order to protect from light.
• Keep out of the reach and sight of children; do not use after the expiry date.
• Do not throw unused medicine into wastewater or household waste – return it to a pharmacy.

Frequently asked questions

Why is Lasix taken in the morning?

The leaflet recommends taking it in the morning (unless the doctor decides otherwise), before a meal with a glass of water. Furosemide increases urination, so a morning dose avoids waking at night to go to the toilet.

Does Lasix lower potassium?

Yes. Hypokalaemia (low potassium) and hyponatraemia are common side effects. The doctor therefore checks blood electrolytes; potassium supplementation should not be started without medical advice.

Can I take ibuprofen with Lasix?

Only on medical advice. NSAIDs (ibuprofen, ketoprofen, indometacin) and higher doses of acetylsalicylic acid can damage the kidneys in dehydrated and elderly people and weaken the medicine’s effect on blood pressure.

Is there also a Lasix injection?

Lasix solution for injection 20 mg/2 mL no longer has a valid authorisation in Serbia (ended in 2026), nor does the 30-tablet pack (ended in 2025). Lasix 40 mg tablets in a pack of 12 have a valid authorisation (renewed on 17.07.2024).

Sources

• ALIMS – Package leaflet Lasix 40 mg tablets (PIL, Serbian)
• ALIMS – Summary of product characteristics Lasix 40 mg tablets (SmPC, Serbian)

Date sources were checked: 25.10.2026.