Lasix

# Lasix ## Overview - **Classification**: Loop Diuretic - **Mechanism**: Inhibits the Na-K-2Cl cotransporter in the thick ascending limb of the loop of Henle, increasing excretion of water, sodium, chloride, and potassium. ## Primary Indications 1. **Edema**: Associated with congestive heart failure, cirrhosis, and renal disease (including nephrotic syndrome). 2. **Hypertension**: As an adjunct, particularly in patients with renal impairment or those unresponsive to thiazides. 3. **Acute Pulmonary Edema**: To rapidly reduce fluid overload. ## Adult Dosing ### Standard Dosing **Edema (CHF, Cirrhosis, Renal Disease)** - **Oral Dose**: **20-80 mg** - **Frequency**: Once daily or twice daily - **Route**: Oral - **Max**: Up to **600 mg/day** (rarely needed) **Acute Pulmonary Edema (IV)** - **Dose**: **40 mg** - **Frequency**: Single IV dose, may repeat with **80 mg** 1 hour later if needed - **Route**: IV push over 1-2 minutes - **Special Considerations**: Higher doses may be used in renal failure, up to **200 mg** IV. **Hypertension** - **Dose**: **20-40 mg** - **Frequency**: Twice daily - **Route**: Oral - **Note**: Often combined with other antihypertensives. ### Dose Adjustments - **Renal Impairment**: - CrCl < 30 mL/min: Higher doses (**40-80 mg** or more) are often required. - Anuria: Contraindicated, except for trial doses. - **Hepatic Impairment**: - Use with caution; monitor for fluid/electrolyte changes and hepatic encephalopathy. - Lower initial doses may be warranted. - **Elderly Patients**: - Start with lower initial doses (e.g., **20 mg**). - Increased risk of dehydration and electrolyte imbalances. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: **0.5-1 mg/kg** - **Frequency**: Every 12-24 hours - **Maximum**: **1 mg/kg/dose** - **Special Notes**: Slower renal elimination. Increased risk of nephrocalcinosis; use with caution. ### Infants (1-12 months) - **Oral Dose**: **1-2 mg/kg** - **Oral Frequency**: Every 6-12 hours - **IV/IM Dose**: **1-2 mg/kg** - **IV/IM Frequency**: Every 6-12 hours - **Maximum**: **6 mg/kg/day** (oral or IV/IM) ### Children (1-12 years) - **Oral Dose**: **1-2 mg/kg** - **Oral Frequency**: Every 6-12 hours - **IV/IM Dose**: **1-2 mg/kg** - **IV/IM Frequency**: Every 6-12 hours - **Maximum**: **6 mg/kg/day** (oral or IV/IM) or **40 mg/dose** for single doses. ### Adolescents (13-18 years) - **Dose**: Generally follows adult dosing, starting with **20-40 mg** - **Frequency**: Once or twice daily - **Maximum**: Up to **600 mg/day** if clinically indicated for severe cases. ## Safety Information ### Contraindications - **Absolute**: Anuria - **Absolute**: Hypersensitivity to furosemide or sulfonamides (possible cross-reactivity). - **Absolute**: Hepatic coma or precomatose states until condition improves. - **Relative**: Severe electrolyte depletion (correct before use). ### Common Adverse Effects - **Very Common (>10%)**: Electrolyte imbalances (hypokalemia, hyponatremia, hypochloremia, hypomagnesemia), dehydration, increased urination. - **Common (1-10%)**: Dizziness, orthostatic hypotension, ototoxicity (especially with rapid IV push or high doses), hyperuricemia, hyperglycemia. - **Serious but Rare**: Agranulocytosis, aplastic anemia, pancreatitis, Stevens-Johnson syndrome (SJS). ### Key Drug Interactions - **Aminoglycosides (e.g., gentamicin)**: Significantly increased risk of irreversible ototoxicity. Avoid concurrent use if possible. - **NSAIDs (e.g., ibuprofen)**: May reduce diuretic efficacy and increase risk of renal toxicity. Monitor BP and renal function. - **Lithium**: Furosemide can decrease renal clearance of lithium, leading to increased lithium levels and toxicity. Monitor lithium levels closely; reduce lithium dose. - **Digoxin**: Increased risk of digoxin toxicity due to furosemide-induced hypokalemia. Monitor potassium and digoxin levels. - **Antihypertensives**: Additive hypotensive effects. Monitor blood pressure closely. ## Monitoring & Follow-up - **Before Treatment**: Baseline electrolytes (Na, K, Cl, Mg, Ca), BUN, creatinine, uric acid, glucose. - **During Treatment**: Electrolytes and renal function (BUN/Cr) frequently (e.g., daily initially, then 2-3 times/week, then weekly/monthly). Monitor blood pressure, weight, and fluid balance. - **Clinical Signs**: Watch for signs of dehydration (e.g., thirst, dry mouth), electrolyte imbalance (e.g., muscle cramps, weakness), and hearing changes. ## Clinical Pearls - 💡 **Timing**: Administer oral doses in the morning to prevent nocturia. If a second dose is needed, give no later than early afternoon. - 💡 **IV Administration**: Administer IV furosemide slowly, typically **over 1-2 minutes** for 20-40 mg, to minimize the risk of ototoxicity. - 💡 **Electrolyte Repletion**: Due to high risk of hypokalemia, consider potassium supplementation for most patients on chronic therapy. - 💡 **Sulfonamide Allergy**: While cross-reactivity is rare, use with caution in patients with severe sulfonamide allergy. - 💡 **Efficacy Check**: Best indicator of effective diuresis for edema is daily weight loss and reduced peripheral/pulmonary congestion. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.