Lasix 40

Tablet · Sanofi
PRESCRIPTION MEDICINE

Lasix 40 is a tablet made by Sanofi that contains Furosemide 40 mg. Furosemide is a strong diuretic (water pill): removes extra fluid in heart failure, kidney or liver disease and swelling.

Ingredient (salt)Amount
Furosemide40 mg

What it is used for

Removes extra fluid in heart failure, kidney or liver disease and swelling.

How it works

A strong loop diuretic (water pill) that removes excess fluid in heart failure, kidney and liver disease, and sometimes lowers blood pressure.

How to take it

Usually 20 to 80 mg in the morning (a second dose before 4 pm if twice daily). Weigh yourself daily if your doctor asks.

Common side effects

  • Passing a lot of urine
  • Thirst
  • Dizziness
  • Low potassium, sodium or magnesium

Get medical help straight away if

  • Muscle cramps, weakness or confusion
  • Hearing problems or ringing in ears
  • Gout
  • Very little urine

Be careful

Causes frequent urination; can lower potassium.

Other medicines and interactions

Raises lithium levels and kidney risk with NSAIDs, ACE inhibitors and ARBs. Low potassium increases digoxin toxicity.

Pregnancy and breastfeeding

Used in pregnancy only if clearly needed; can reduce milk supply.

Same composition, other brands (3)

Lasipen 40Frusamide 40Frusenex 40

Ask your doctor or pharmacist before switching brands.

Same ingredients, different strength or form

Lasix Injection

Common questions

What is Lasix 40?

Lasix 40 is a tablet by Sanofi containing Furosemide 40 mg.

What is Lasix 40 used for?

Removes extra fluid in heart failure, kidney or liver disease and swelling.

How should I take Lasix 40?

Usually 20 to 80 mg in the morning (a second dose before 4 pm if twice daily). Weigh yourself daily if your doctor asks. Always follow the dose your doctor or the pack gives.

What are the side effects of Lasix 40?

Common side effects include: Passing a lot of urine, thirst, dizziness, low potassium, sodium or magnesium. Get medical help straight away for: Muscle cramps, weakness or confusion, hearing problems or ringing in ears, gout, very little urine.

Does Lasix 40 need a prescription?

Yes. In India it is a prescription (Schedule H) medicine, so a pharmacist should sell it only with a doctor's prescription.

Can I take Lasix 40 in pregnancy or while breastfeeding?

Used in pregnancy only if clearly needed; can reduce milk supply.

What are the substitutes for Lasix 40?

Brands with the same composition: Lasipen 40, Frusamide 40, Frusenex 40. Ask your doctor or pharmacist before switching.

Sources and further reading

NHS (UK National Health Service) and MedlinePlus (US National Library of Medicine) are free, reviewed medicine guides. Brand names and doses there may differ from India.

Composition checked against pack details from large Indian online pharmacies. Last reviewed 31 October 2026. Written by Satya Babu.

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For information only, not medical advice. This page is a plain-language summary written from standard prescribing information and the public guides linked below. Brands sometimes change their formula, so always check the composition printed on the pack. Doses here are typical adult doses; yours may differ. Do not start, stop or change a medicine without your doctor or pharmacist, and keep all medicines away from children. In an emergency, call 112 (India) or your local emergency number.