Medication Overview

Lasix, also known by its generic name furosemide, is a potent diuretic commonly prescribed for the management of fluid retention (edema) associated with congestive heart failure, liver disease, or kidney disorders. It works by prompting the kidneys to eliminate excess salt and water from the body through urine.

Pharmacological Classification

Lasix belongs to the loop diuretics drug class, targeting the Na-K-2Cl co-transporter in the ascending limb of the loop of Henle in the nephron. This action impedes sodium, potassium, and chloride reabsorption, resulting in an increased excretion of these electrolytes and water.

Dosage Forms

Lasix is available in oral tablets, oral solution, and injectable forms. Oral tablets are commonly available in 20 mg, 40 mg, and 80 mg strengths. The injectable form is typically reserved for patients requiring rapid diuretic action or those unable to take oral medications.

Indications for Use

Primarily indicated for edema management due to congestive heart failure, hepatic cirrhosis, and renal dysfunction. Additionally, Lasix is prescribed for the treatment of hypertension, either alone or in combination with other antihypertensive agents.

Mechanism of Action

Lasix acts by inhibiting the reabsorption of sodium and chloride in the loop of Henle, leading to increased urine output. This diuretic effect reduces blood plasma volume, thereby lowering blood pressure and decreasing fluid retention.

Recommended Dosage

The initial dose for adults can vary, typically between 20 mg to 80 mg for oral administration, taken once daily. Dosage adjustments may be made based on the patient’s response and clinical condition. For pediatric patients, the dosage is calculated based on body weight, generally starting at 1 mg/kg.

Administration Guidelines

Lasix should be taken with plenty of fluids, preferably in the morning or early afternoon to avoid nocturnal diuresis. The injectable form should be administered by a healthcare professional, typically via intravenous or intramuscular injection.

Pharmacokinetics Overview

Lasix is rapidly absorbed from the gastrointestinal tract, with peak plasma concentrations occurring about 1-2 hours post-ingestion. The medication exhibits a half-life of approximately 2 hours and is primarily eliminated via renal excretion.

Drug Interactions

Lasix may interact with several other medications, including but not limited to aminoglycoside antibiotics, digoxin, corticosteroids, and nonsteroidal anti-inflammatory drugs (NSAIDs). Combination with these drugs may enhance renal toxicity, hypokalemia, or increase the risk of other side effects.

Renal Function Impact

Patients with impaired renal function may exhibit altered pharmacokinetics of Lasix. Decreased renal clearance can lead to prolonged drug action and necessitate dosage adjustments to avoid toxicity.

Hepatic Disease Considerations

In patients with hepatic cirrhosis, Lasix may precipitate hepatic encephalopathy or electrolyte imbalances. Such patients should be closely monitored, and dose titration should be performed with caution.

Potential Side Effects

Common side effects of Lasix include dehydration, electrolyte imbalances (e.g., hypokalemia, hypomagnesemia), dizziness, and hypotension. Rare but serious adverse effects may include ototoxicity and acute pancreatitis.

Overdose Management

Overdosage symptoms may include severe dehydration, electrolyte disturbance, and hypotension. Management typically involves supportive care, fluid, and electrolyte replenishment. Hemodialysis is generally not effective due to high plasma protein binding.

Contraindications Overview

Lasix is contraindicated in patients with anuria, known hypersensitivity to furosemide or sulfonamides, and severe electrolyte depletion. Care should be taken in patients with hepatic coma or severe renal impairment without sufficient urinary output.

Special Population Considerations

Elderly patients may require lower initial doses and careful monitoring due to the increased risk of renal and cardiovascular adverse effects. Pregnant and breastfeeding women should only use Lasix if the potential benefits justify the potential risks.

Therapeutic Monitoring

Regular monitoring of electrolytes, renal function, and blood pressure is essential during Lasix therapy to ensure efficacy and minimize adverse effects. Periodic assessment of hearing is recommended due to the risk of ototoxicity.

Storing and Handling Information

Lasix should be stored at room temperature, away from moisture and light. The injectable form should be inspected visually for particulate matter or discoloration prior to administration. Keep the medication out of reach of children.