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furosemide (Lasix, Furoscix)

Tradename: Lasix (LAsts for SIX hours). Indications: 1) hypertension 2) heart failure 3) edema, including peripheral edema & pulmonary edema 4) IV form used to increase renal excretion of Ca+2 in patients with hypercalcemia 5) empiric treatment of oliguria Contraindications: - of no benefit in acute renal failure [5] Dosage: - 1 mg/kg up to 20-80 mg IV - IV infusion: 40 mg loading dose, then 2-200 mg/hr - subcutaneous self-administration (Furoscix) 80 mg dose over 5 hours [7] - 20-80 mg PO QD/BID - Max dose: a) 160 mg/day (hepatic failure), b) 240 mg/day (nephrotic syndrome) c) 600 mg/day (CHF with normal renal function) [6] d) doses as large as 2.5 g/day have been used Tabs: 20, 40, 80 mg. Solution 10 & 40 mg/5 mL. Furoscix: single-use pre-filled cartridge attaches to the patient's abdomen [7] Pharmacokinetics: 1) absorption is erratic 2) 96-99% is bound to plasma proteins 3) renal clearance is by active secretion 4) onset of diuresis within 30-60 minutes (PO) 5 min (IV) 5) peak effect in 1-2 hours; reduced & delayed in the elderly 6) duration of action: 6-8 hours 7) 50-80% of IV dose & 20-55% of PO dose is excreted unchanged in the urine 8) 1/2life is about 90 minutes, increased in patients with cirrhosis, CHF & end-stage renal disease (ESRD) Adverse effects: 1) common (> 10%) - orthostatic hypotension 2) less common (1-10%) - electrolyte disorder, blurred vision, diarrhea, headache, photosensitivity, loss of appetite, abdominal pain 3) uncommon (< 1%) - rash, injection site erythema, hyperuricemia, gout, hepatic dysfunction - agranulocytosis, leukopenia, anemia, thrombocytopenia - ototoxicity, pancreatitis, xanthopsia, nausea - nephrocalcinosis, prerenal azotemia, interstitial nephritis 4) other - hypocalcemia - K+ depletion - Ca+2 & Mg+2 depletion - hypochloremic alkalosis - dilutional hyponatremia - hyperglycemia - glucosuria - hypercholesterolemia (mild) total & LDL - vasculitis - reaction to sulfa-drugs (cross-sensitivity) - pseudo-porphyria cutanea tarda - bullous pemphigoid [8] Drug interactions: 1) drugs that cause K+ depletion, i.e. beta-2 agonists 2) decreased lithium clearance 3) increased requirements of insulin &/or sulfonylureas 4) probenecid 5) increased risk of renal failure in combination with NSAIDs 6) enhancement of effects of muscle relaxants Mechanism of action: 1) inhibits resorption of electrolytes in the ascending loop of Henle 2) decreases the reabsorption of Na+ & Cl- 3) increases K+ excretion in the distal renal tubule 4) other electrolytes affected include: Ca+2, Mg+2, NH4+, HCO3- & phosphate 5) Lasix acutely reduces preload via a direct venodilation in addition to its diuretic effect; thus furosemide is particularly useful in the setting of congestive heart failure & pulmonary edema

Interactions

drug interactions drug adverse effects (more general classes) monitor with drug (more general classes)

General

loop diuretic sulfanilamide

Properties

MISC-INFO: elimination route KIDNEY pregnancy-category C safety in lactation ?

Database Correlations

PUBCHEM correlations

References

  1. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
  2. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
  3. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 473
  4. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  5. Ho KM and Sheridan DJ Meta-analysis of furosemide to prevent or treat acute renal failure. BMJ 2006, 333:420 PMID: 16861256
  6. Medical Knowledge Self Assessment Program (MKSAP) 15, American College of Physicians, Philadelphia 2009
  7. Lou N FDA Approves At-Home Furosemide for Heart Failure. Strong diuretic to become available outside the hospital setting. MedPage Today October 10, 2022 https://www.medpagetoday.com/cardiology/chf/101139
  8. NEJM Knowledge+ Dermatology - Lee JJ, Downham TF 2nd. Furosemide-induced bullous pemphigoid: case report and review of literature. J Drugs Dermatol. 2006 Jun;5(6):562-4. PMID: 16774111 Review.

Component-of

amiloride/furosemide