Furosemide (Lasix)
Loop diuretic that inhibits sodium-potassium-chloride co-transporter in the thick ascending limb of the loop of Henle. Rapidly absorbed orally with variable bioavailability (10-100%). Eliminated ~65% unchanged renally via active secretion; ~35% metabolized. Used for edema, heart failure, hypertension. Short plasma half-life but potent diuretic effect. Highly protein-bound (~99%), which may reduce renal excretion in renal failure.
Projected serum levels — 40 mg, once daily
Maintenance schedule: 40 mg once daily (oral).
Modeled steady state after ~1 days: peak ≈ 14.0 mg, trough ≈ 0.006 mg body load. Population-based estimate over 15 days for a 40 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.
Key facts
- Category
- Diuretic
- Route modeled
- Oral
- Model confidence
- inferred
- Half-life
- 2 h
- Common dose
- 40 mg
- Suggested maximum
- 600 mg/day
- Reference dose range
- 20–600 mg (single dose)
- Suggested cadence
- once daily
- Validated against
- 40 mg oral — Cmax 1.4 mg/L at 1 h
Documented interactions
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danger
CBD (Cannabidiol) + Furosemide (Lasix)
CBD (Cannabidiol) reversible_inhibitor of UGT1A9 predicted to change Furosemide (Lasix) AUC by ~3.33x
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danger
Levothyroxine (Synthroid) + Furosemide (Lasix)
Furosemide (Lasix) may displace Levothyroxine (Synthroid) from plasma protein binding sites, transiently raising free drug concentration. This drug has a narrow therapeutic index; free concentration…
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danger
Tacrolimus (Prograf) + Furosemide (Lasix)
Furosemide (Lasix) may displace Tacrolimus (Prograf) from plasma protein binding sites, transiently raising free drug concentration. This drug has a narrow therapeutic index; free concentration…
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danger
Warfarin (Coumadin) + Furosemide (Lasix)
Furosemide (Lasix) may displace Warfarin (Coumadin) from plasma protein binding sites, transiently raising free drug concentration. This drug has a narrow therapeutic index; free concentration…
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warning
Apigenin + Furosemide (Lasix)
Apigenin may displace Furosemide (Lasix) from plasma protein binding sites, transiently raising free drug concentration.
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warning
Aripiprazole (Abilify) + Furosemide (Lasix)
Furosemide (Lasix) may displace Aripiprazole (Abilify) from plasma protein binding sites, transiently raising free drug concentration.
Serum checks 146 modeled interaction pairings for furosemide (lasix) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.
Research behind this entry
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Disposition and absolute bioavailability of furosemide in healthy males
Comprehensive pharmacokinetic study establishing furosemide bioavailability range of 10-100% with high inter-individual variability due to erratic GI absorption and active renal secretion as primary elimination route.
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Pharmacokinetics and metabolism of furosemide in man
Foundational study demonstrating hepatic metabolism accounts for ~35% of furosemide elimination, with renal excretion of intact drug as primary route. Shows non-linear pharmacokinetics at higher doses.
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Diuretic therapy
Clinical review of diuretic therapy mechanisms and clinical pharmacology, discussing furosemide as the most frequently prescribed loop diuretic with well-understood effects on renal hemodynamics and electrolyte…
3 published studies referenced in the app, each with a plain-language summary.