Medicines & Supplements A to Z > Lasix


Last updated on 19/10/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  

GENERIC NAME: Frusemide / Furosemide


DRUG CLASS: Diuretics

SUB CLASS: Loop diuretics

USED FOR: High blood pressure, Oedema

– 40mg (tablets)
– 20mg/2ml, 250mg/25ml (injection)

What is Lasix for?

Lasix is a brand product that contains Frusemide (or called Furosemide), which is a class of medication called loop diuretic. It helps excrete excessive amounts of salt and water in your body, hence increasing urine output. Lasix is therefore used to treat high blood pressure and oedema.

How to use it?

Lasix is available as tablets or injections. 

For oedema, the usual initial dose is 20-80 mg once daily in the morning. For maintenance, the dose should be individualized and given once or twice daily.

For hypertension, the usual initial dose is 80 mg, divided into 40 mg twice a day. Dosage should then be adjusted according to response.

If it is used as twice-daily dosing, the second dose is usually taken around lunchtime to avoid over-peeing at night. For example, taken at 8 am and 2 pm respectively.

What are the side effects of Lasix?

Common side effects of Lasix include dizziness, decreased potassium level, tiredness, nausea, and headache.

Who should not take Lasix?

– People who are allergic to Frusemide or any ingredient of the formulation
– Patients who are unable to pass out urine (anuria)

Pharmacist Tips:

– Call your doctor right away if you have ringing in the ears or any change in your hearing.
– Drink plenty of water to avoid dehydration.
– Continue taking Lasix even when you feel well.

Common dosing schedule:
Lasix should be taken once daily in the morning, or twice daily (at 8 am and 2 pm).

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Lasix may interact with:
– Angiotensin-converting enzyme inhibitors, e.g. Captopril, Lisinopril
– Non-steroidal anti-inflammatory drugs, e.g. Diclofenac, Ibuprofen
– Atypical antipsychotics, e.g. Aripiprazole, Clozapine

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Lasix in Hong Kong?

In Hong Kong, Lasix is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

Need more information?

For detailed information about the use of Lasix in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.