Furosemide (Lasix)
4-chloro-2-(furfurylamino)-5-sulfamoylbenzoic acid. Diuretic, loop diuretic.
This page describes what Furosemide (Lasix) is and its known risks. It is not medical advice and not a guide to using it. Many of these substances are prescription-only or illegal to use without a prescription. Speak to a doctor.
- Class
- Diuretic
- Legal status
- Prescription only
- Half-life
- 2 hours
- Liver strain
- Low
- Kidney strain
- Moderate-High (with misuse)
- Converts to estrogen
- None
- Suppresses natural hormones
- Not typically
Medical uses
- Edema
- Congestive heart failure
- Hypertension
What it does in the body
Other
- Rapid, significant fluid loss
- Reduced subcutaneous water retention (visual 'dryness')
Forms, half-life and detection
| Form | Half-life | Reported detection window |
|---|---|---|
| Oral or Injectable | 2 hours | 1-2 days |
Side effects and health risks
Metabolic
- Severe electrolyte depletion (potassium, sodium, magnesium)
- Dehydration
Heart and blood vessels
- Dangerous drops in blood pressure
- Arrhythmias (from electrolyte loss — a real cause of on-stage cardiac events)
Kidneys
- Kidney strain
- Risk of acute kidney injury if misused
Neurological
- Muscle cramps
- Dizziness
- Fainting
Blood tests worth monitoring
From its known properties, these are the markers doctors commonly check. Getting blood work before, during and after is how problems are caught early.
- Kidney strain: Moderate-High (with misuse): Creatinine, BUN, eGFR
Related compounds
Questions
What is the half-life of Furosemide (Lasix)?
About 2 hours. Half-life is the time for the level in the blood to fall by half.
How long is Furosemide (Lasix) detectable?
Testing windows of 1-2 days are reported, depending on the test and the person.
Is Furosemide (Lasix) legal?
Prescription only. Laws differ by country and change; check the rules where you live.
What blood tests matter with Furosemide (Lasix)?
Based on its properties, these markers are commonly monitored: Creatinine, BUN and eGFR. A doctor can order and interpret them.
What are the side effects of Furosemide (Lasix)?
Metabolic: severe electrolyte depletion (potassium, sodium, magnesium) and dehydration. Heart and blood vessels: dangerous drops in blood pressure and arrhythmias (from electrolyte loss — a real cause of on-stage cardiac events). Kidneys: kidney strain and risk of acute kidney injury if misused.
For information only, not medical advice. MyoStats is a tracking tool used at your own discretion. Speak to a doctor before changing your training, diet, medication or anything you take.