Furosemide

Furosemide

Drug monograph · NCLEX study reference
Trade names	Lasix
Therapeutic class	Diuretic, antihypertensive
Pharmacologic class	Loop diuretic
Onset / peak / duration	PO onset 30 to 60 minutes; IV onset about 5 minutes; duration 6 to 8 hours PO, 2 hours IV.
Half-life / level	Half-life about 2 hours; no routine level.
Routes	PO (oral), IV
High-alert (ISMP)	No
Black box warning	Yes (see Safety)
Antidote / reversal	None; correct fluids and electrolytes.
Pregnancy / lactation	Use only if clearly needed.

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Furosemide (brand name Lasix) — Diuretic, antihypertensive; Loop diuretic.

Identification

• Therapeutic class: Diuretic, antihypertensive.
• Pharmacologic class: Loop diuretic.

Pharmacology

• Mechanism of action: Inhibits sodium, potassium, and chloride reabsorption in the loop of Henle, producing potent diuresis.
• Onset / peak / duration: PO onset 30 to 60 minutes; IV onset about 5 minutes; duration 6 to 8 hours PO, 2 hours IV.
• Half-life / therapeutic level: Half-life about 2 hours; no routine level.

Clinical use

• Indications: Edema from heart failure, renal or hepatic disease, pulmonary edema, hypertension.
• Usual dose, route, frequency: 20 to 80 mg PO or IV, sometimes higher and more frequent.
• Maximum dose / adjustments: Doses increase substantially in renal impairment; push IV slowly (no faster than 20 mg/min) to avoid ototoxicity.

Safety

• Contraindications: Anuria, severe electrolyte depletion, hypersensitivity.
• Black box warning: Profound diuresis can cause fluid and electrolyte depletion; dosing must be individualized with close monitoring.
• Interactions: Digoxin (hypokalemia toxicity), aminoglycosides (additive ototoxicity), lithium, NSAIDs (reduced effect), corticosteroids.
• Pregnancy / lactation: Use only if clearly needed.
• High-alert: No.

Adverse effects

• Common side effects: Increased urination, hypokalemia, hyponatremia, dizziness, orthostatic hypotension.
• Serious effects to report: Severe dehydration, ototoxicity (hearing loss, tinnitus), profound hypokalemia, acute kidney injury.
• Antidote / reversal: None; correct fluids and electrolytes.

Nursing process

• Assessment before administration: Weight, blood pressure, intake and output, electrolytes (especially potassium), renal function, hearing.
• Interventions during therapy: Give early in the day; push IV slowly; daily weights; monitor for hypokalemia.
• Monitor: Electrolytes, weight, intake and output, renal function, blood pressure.
• Evaluation / expected outcome: Reduced edema, weight loss, improved breathing.

Patient teaching

• Patient teaching: Take in the morning; eat potassium-rich foods; rise slowly.
• Notify provider if: Muscle cramps or weakness, hearing changes, severe dizziness, very low urine output.
• Administration tips: Morning dosing; IV pushed slowly.