furosemide (Lasix, Furoscix)
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Introduction
Tradename: Lasix (LAsts for SIX hours).
Indications
- hypertension
- heart failure
- edema, including peripheral edema & pulmonary edema
- IV form used to increase renal excretion of Ca+2 in patients with hypercalcemia
- 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:
- 160 mg/day (hepatic failure),
- 240 mg/day (nephrotic syndrome)
- 600 mg/day (CHF with normal renal function)[6]
- 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
- absorption is erratic
- 96-99% is bound to plasma proteins
- renal clearance is by active secretion
- onset of diuresis within 30-60 minutes (PO) 5 min (IV)
- peak effect in 1-2 hours; reduced & delayed in the elderly
- duration of action: 6-8 hours
- 50-80% of IV dose & 20-55% of PO dose is excreted unchanged in the urine
- 1/2life is about 90 minutes, increased in patients with cirrhosis, CHF & end-stage renal disease (ESRD)
elimination via kidney
Adverse effects
- common (> 10%)
- less common (1-10%)
- uncommon (< 1%)
- 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 adverse effects of loop diuretics
- drug adverse effects of sulfonamides
- drug adverse effects of diuretics
- drug adverse effects of carbonic anhydrase inhibitor(s)
- drug adverse effects of antihypertensive agents
Drug interactions
- drugs that cause K+ depletion, i.e. beta-2 agonists
- decreased lithium clearance
- increased requirements of insulin &/or sulfonylureas
- probenecid
- increased risk of renal failure in combination with NSAIDs
- enhancement of effects of muscle relaxants
- drug interaction(s) anticonvulsants with anti-bacterial agents
- drug interaction(s) SGLT2 inhibitors (flozins) with diuretics
- drug interaction(s) of diuretics in combination with Zn+2
- drug interaction(s) of antiarrhythmic agents in combination with diuretics
- drug interaction(s) of beta-2 adrenergic receptor agonists with loop diuretics
- drug interaction(s) of calcium channel blockers with diuretics
- drug interaction(s) of antibiotics with warfarin
- drug interaction(s) of lithium carbonate with loopt diuretics
- drug interaction(s) of beta-adrenergic receptor antagonists with loop diuretics
- drug interaction(s) of diuretics with angiotensin II receptor antagonists
- drug interaction(s) of diuretics with ACE inhibitors
- drug interaction(s) of loop diuretics with alpha-1 adrenergic receptor antagonist
- drug interaction(s) of NSAIDs, diuretics & angiotensin II receptor antagonists
- drug interaction(s) of NSAIDs, diuretics & ACE inhibitors
- drug interaction(s) of NSAIDs & antihypertensives
- drug interaction(s) of NSAIDs & loop diuretics
Mechanism of action
- inhibits resorption of electrolytes in the ascending loop of Henle
- decreases the reabsorption of Na+ & Cl-
- increases K+ excretion in the distal renal tubule
- other electrolytes affected include: Ca+2, Mg+2, NH4+, HCO3- & phosphate
- 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
More general terms
Component of
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- ↑ Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 473
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ 5.0 5.1 Ho KM and Sheridan DJ Meta-analysis of furosemide to prevent or treat acute renal failure. BMJ 2006, 333:420 PMID: https://www.ncbi.nlm.nih.gov/pubmed/16861256
- ↑ 6.0 6.1 Medical Knowledge Self Assessment Program (MKSAP) 15, American College of Physicians, Philadelphia 2009
- ↑ 7.0 7.1 7.2 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
- ↑ 8.0 8.1 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: https://www.ncbi.nlm.nih.gov/pubmed/16774111 Review.