II. Indications
- See Loop Diuretic
III. Precautions
- Lasix (named for LAst SIX) is only effective for 6 hours
- Optimal dosing is given at least twice daily (patient otherwise is Sodium avid 18 hours/day)
IV. Pharmacokinetics
- Oral
- Onset: 1 hour
- Half-Life: 1 to 1.5 hours
- Duration: 6 to 8 hours
- Highly variable Bioavailability on oral ingestion (typically 50%, varies between 10 and 90%)
- Increased Bioavailability when taken with meals
- Gastrointestinal absorption is markedly decreased in severe edema (e.g. CHF exacerbation)
- Contrast with Torsemide which has excellent and consistent Bioavailability
- Intravenous
- Onset: 5 minutes
- Duration: 2 hours
- Protein-Binding: 95%
- Eliminated unchanged in urine
- Higher doses (2-3x) required for Nephrotic Syndrome
- Renal dysfunction results in decreased response and increased Half-Life
- Only 15-20% of Furosemide dose is delivered to the renal tubule in stage 5 CKD
V. Mechanism
- See Loop Diuretic
VI. Dosing: Oral (adults)
- Start: 20 to 40 mg orally daily to twice daily
- Twice daily dosing is recommended due to short duration of activity
- Maximum: 600 mg/day (rare to exceed 400 mg/day)
- Peak effect at 1 to 1.5 hours after oral dose
- Duration: 6-8 hours
VII. Dosing: Intravenous (adults)
- Intravenous dose is typically one half of oral dose
- In exacerbations, the oral dose is often used IV
- Administer slowly over 1-2 minutes
- Doses higher than 80 mg should infuse slowly to avoid Ototoxicity
- Bolus
- Dose 20 to 40 mg IV (0.5-1.0 mg/kg, max 2 mg/kg)
- In CHF exacerbations, 60 mg IV is often given
- In Renal Insufficiency, consider starting dose = 40 * sCr
- Where sCr = Serum Creatinine
- Reflects the diminishing effect of Furosemide as Serum Creatinine increases (and GFR drops)
-
Pharmacokinetics
- Onset: Diuresis starts within 10 minutes
- Peak effect in 10-30 minutes
- Duration: 6 hours
- Peak Diuretic effect of repeat dosing is 25% of the first dose
- Compensatory Sodium retention may be overcome by frequent IV doses or continuous infusion
- Maximum effective dose (ceiling dose)
- Chronic Kidney Disease or Nephrotic Syndrome: 80 to 200 mg
- Congestive Heart Failure or Cirrhosis: 40-80 mg
VIII. Dosing: Intravenous Infusion (adults)
- Background
- More effective at maintaining a constant increased Urine Output with less adverse effects (e.g. Ototoxicity)
- Maximum diuresis at 3 hours after continuous infusion started
- Precautions
- Very high dose Furosemide infusions (4 mg/min) risk Ototoxicity
- Loading dose: 40-200 mg
- Loading doses higher than 80 mg should infuse slowly to avoid Ototoxicity
- Infusion dose
- Start: 10-20 mg/hour (0.25 to 0.75 mg/kg/hour) IV
- Maximum: 40 mg/hour IV
IX. Dosing: Child
- IV/IM/PO
- Start: 0.5 to 2 mg/kg/dose IV/IM/PO every 6 to 12 hours
- Max: 6 mg/kg/dose
- Intravenous Infusion
- Start: 0.05 mg/kg/hour and titrate
X. Adverse Effects
- See Loop Diuretic
- Ototoxocity
- See Loop Diuretic
- Most common with high doses or rapid infusion rates (>4 mg/min)
- Decreased Thyroid Hormone levels
- Associated with Furosemide doses >80 mg/day
XI. Drug Interactions
- Warfarin
-
Cyclosporine
- Cyclosporine decreases Uric Acid excretion, and increased gout risk when used with Furosemide
-
Lithium
- Avoid use with Furosemide
- Agents that decrease Furosemide Diuretic effect
- Indomethacin
- Probenacid
XII. Safety
- Pregnancy Category C
- Unknown Safety in Lactation
XIII. Resources
- Furosemide Tablets (DailyMed)
- Furosemide Intravenous Solution (DailyMed)
XIV. References
- (2021) Presc Lett, Resource #370507, Commonly Used Diuretics
- (2020) Med Lett Drugs Ther 62(1598): 73-80
- Hamilton (2020) Tarascon Pocket Pharmacopoeia
- Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 62-3
- Won Oh (2015) Electrolyte Blood Press 13(1):17-21 +PMID: 26240596 [PubMed]
Images: Related links to external sites (from Bing)
Related Studies
| furosemide (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| FUROSEMIDE 10 MG/ML SOLUTION | Generic | $0.09 per ml |
| FUROSEMIDE 100 MG/10 ML VIAL | Generic | $0.34 per ml |
| FUROSEMIDE 20 MG TABLET | Generic | $0.03 each |
| FUROSEMIDE 40 MG TABLET | Generic | $0.03 each |
| FUROSEMIDE 40 MG/4 ML VIAL | Generic | $0.34 per ml |
| FUROSEMIDE 80 MG TABLET | Generic | $0.05 each |
| lasix (on 2/22/2023 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| LASIX 40 MG TABLET | Generic | $0.03 each |
Ontology: Furosemide (C0016860)
| Definition (CHV) | a drug used as a diuretic |
| Definition (CHV) | a drug used as a diuretic |
| Definition (CHV) | a drug used as a diuretic |
| Definition (NCI) | A sulfamoylanthranilic acid derivative, also known as frusemide, and potent loop diuretic. Furosemide is widely used to treat hypertension and edema. This agent is highly bound to albumin and is largely excreted unchanged in the urine. |
| Definition (CSP) | sulfamyl saluretic and diuretic; has a fast onset and short duration of action and is used in edema and chronic renal insufficiency. |
| Definition (MSH) | A benzoic-sulfonamide-furan. It is a diuretic with fast onset and short duration that is used for EDEMA and chronic RENAL INSUFFICIENCY. |
| Definition (PDQ) | An anthranilic derivative and loop diuretic with antihypertensive effect. Furosemide blocks the Na-K-Cl cotransporter (NKCC) in the luminal membrane of the thick ascending limb of the loop of Henle in the kidney, by binding to the Cl-binding site located in the cotransporter's transmembrane domain, thereby inhibiting reabsorption of sodium, chloride, potassium ions and water. This agent reduces plasma and extracellular fluid volume resulting in decreased blood pressure and cardiac output. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=39247&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=39247&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C515" NCI Thesaurus) |
| Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
| MSH | D005665 |
| SnomedCT | 387475002, 81609008 |
| LNC | LP32693-1, LP16155-1, MTHU016795 |
| English | Frusemid, Frusemide, Fursemide, Benzoic acid, 5-(aminosulfonyl)-4-chloro-2-((2-furanylmethyl)amino)-, Furosemide, furosemide, FRS, FUROSEMIDE, furosemide (medication), Furosemide [Chemical/Ingredient], frusemide, fursemide, Furosemide (product), Furosemide (substance) |
| Swedish | Furosemid |
| Czech | furosemid |
| Finnish | Furosemidi |
| Russian | FRUSEMID, FUROSEMID, FURSEMID, ФРУСЕМИД, ФУРОСЕМИД, ФУРСЕМИД |
| Italian | Fursemide, Frusemide, Furosemide |
| Croatian | FUROSEMID |
| Spanish | frusemida, furosemida (producto), furosemida (sustancia), furosemida, Frusemida, Furosemida, Fursemida |
| Polish | Furosemid, Lasix |
| Japanese | フルセミド, フロセミド |
| French | Furosémide |
| German | Frusemid, Furosemid, Fursemid |
| Portuguese | Frusemida, Furosemida, Fursemida |
Ontology: Lasix (C0699992)
| Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
| MSH | D005665 |
| English | lasix, Lasix |
