Lasix 40 mg Tablets

Brand Name

This medication is marketed under the trade name Lasix, a label widely acknowledged among healthcare professionals for its potent diuretic effects.

International Nonproprietary Name (INN)

The active ingredient is identified globally as furosemide, ensuring its consistent recognition across medical practices worldwide.

Form of Release

The drug is available in multiple forms, including tablets for oral administration, an oral solution, and an injectable solution for intravenous or intramuscular use. These options come in various strengths, providing flexibility to meet diverse therapeutic needs while maintaining stability under standard storage conditions.

Composition

Furosemide serves as the primary active substance, designed to influence fluid and electrolyte balance within the body. In tablets, inactive ingredients such as lactose monohydrate, corn starch, magnesium stearate, and colloidal anhydrous silica contribute to structural integrity and facilitate dissolution. The oral solution includes sweeteners like sorbitol and preservatives such as sodium benzoate to enhance palatability and shelf life. The injectable form contains sodium hydroxide and sodium chloride to adjust pH and ensure compatibility with bodily fluids. Each component is carefully chosen to support the therapeutic action of furosemide without compromising its efficacy.

Pharmacologic Properties

Pharmacodynamics

This medication operates as a loop diuretic, targeting the sodium-potassium-chloride cotransporter in the thick ascending limb of the loop of Henle within the kidneys. By inhibiting this transporter, it prevents reabsorption of sodium, chloride, and potassium, leading to a significant increase in water excretion through urine. This action reduces blood volume and extracellular fluid, effectively lowering blood pressure and alleviating edema. It also exerts a mild vasodilatory effect on venous capacitance vessels, reducing preload on the heart. Effects begin rapidly, within 30 minutes of oral administration or five minutes of intravenous use, peaking at one to two hours and lasting up to six hours. This rapid and potent diuresis makes it a critical tool for managing fluid overload states.

Pharmacokinetics

Following oral administration, the drug absorbs variably from the gastrointestinal tract, with bioavailability ranging from 50% to 70%, influenced by food or gastrointestinal conditions. Intravenous delivery achieves 100% bioavailability, with immediate onset. Peak plasma concentrations occur within one to two hours for oral forms and almost instantly for injections. Furosemide binds approximately 95% to plasma proteins, primarily albumin, and distributes into extracellular fluid, reaching the kidneys efficiently. It undergoes minimal hepatic metabolism, with about 50% excreted unchanged in urine via glomerular filtration and tubular secretion. The half-life averages one to two hours but may extend in renal or hepatic impairment due to reduced clearance. Elimination is predominantly renal, with a small fraction appearing in bile and feces.

Indications for Use

This medication is prescribed for conditions requiring rapid and effective fluid removal. It treats edema associated with congestive heart failure, reducing swelling and easing cardiac strain by decreasing fluid volume. It is also indicated for edema linked to liver cirrhosis or nephrotic syndrome, helping to manage ascites or peripheral fluid accumulation. In acute pulmonary edema, it provides quick relief by reducing pulmonary congestion and improving oxygenation. Hypertension benefits from its ability to lower blood volume, particularly in resistant cases or emergencies. Additionally, it may be used in hypercalcemia to enhance calcium excretion and in renal failure to stimulate urine output when residual function remains. Its versatility supports both acute and chronic management of these states.

Contraindications

Certain conditions preclude the use of this drug to avoid serious health risks. Hypersensitivity to furosemide or sulfonamide-derived compounds prohibits its administration, as reactions could range from rashes to anaphylaxis. Severe renal failure with anuria, where no urine is produced, contraindicates it, as its action depends on kidney function. Significant electrolyte imbalances, such as hypokalemia, hyponatremia, or hypomagnesemia, must be corrected first to prevent exacerbation. It is avoided in severe dehydration or hypovolemia, where further fluid loss could lead to circulatory collapse. Hepatic coma or pre-coma states also limit its use due to risks of worsening electrolyte shifts. Caution is required in patients with gout, as it may elevate uric acid levels.

Method of Administration and Dosage

How to Take

Tablets or oral solution are taken by mouth, preferably in the morning to avoid nocturnal urination, and can be consumed with or without food. Swallowing tablets whole with water or measuring the oral solution accurately ensures proper delivery. The injectable form is administered intravenously or intramuscularly by healthcare professionals, often in acute settings. Consistent timing supports predictable fluid management.

Dosage for Adults and Children

For adults with edema, treatment typically starts at 20 mg to 80 mg daily for oral forms, adjustable up to 600 mg daily in divided doses based on response, while intravenous doses begin at 20 mg to 40 mg, repeated as needed. In hypertension, 40 mg twice daily is common, tailored to blood pressure goals. Acute pulmonary edema often requires 40 mg intravenously, with additional doses if necessary. Children receive 1 mg to 2 mg per kilogram daily for oral or intravenous use, divided into one or two doses, with a maximum of 6 mg per kilogram daily, adjusted under specialist supervision. Fluid and electrolyte monitoring guides dosing to balance efficacy and safety.

Dose Adjustment in Specific Conditions

Renal impairment requires higher doses if some function remains, starting at 80 mg to 120 mg daily, though it’s avoided in anuria. Hepatic dysfunction suggests lower initial doses, such as 20 mg daily, due to altered fluid dynamics and risk of encephalopathy from electrolyte shifts. Elderly patients or those with reduced renal reserve may begin with 20 mg daily to prevent dehydration or hypotension. Gradual titration and frequent laboratory assessments ensure dosing aligns with individual physiological capacity, particularly in compromised states.

Side Effects

This medication may elicit a variety of unintended reactions, varying in frequency and severity. Dehydration, thirst, or dry mouth are common, reflecting significant fluid loss, especially if intake isn’t adjusted. Electrolyte imbalances, including low potassium, sodium, or magnesium, can cause muscle cramps, weakness, or irregular heartbeats. Dizziness or lightheadedness might occur due to blood pressure drops or volume depletion, particularly early in therapy. Gastrointestinal disturbances like nausea, vomiting, or diarrhea affect some users but often subside with time. Rarely, severe effects such as ototoxicity—ringing in the ears or hearing loss—or allergic reactions like rash or jaundice emerge, requiring immediate medical attention. Regular monitoring mitigates these risks effectively.

Overdose

Symptoms of Overdose

Excessive intake can lead to profound dehydration, manifesting as extreme thirst, confusion, or lethargy from rapid fluid loss. Hypotension may result, causing dizziness, fainting, or shock due to reduced blood volume. Electrolyte disturbances, such as severe hypokalemia or hyponatremia, might trigger muscle paralysis, arrhythmias, or seizures, posing life-threatening risks. Symptoms typically arise within hours and escalate without intervention, reflecting the drug’s potent diuretic action.

First Aid Measures

In an overdose situation, discontinue administration immediately and seek urgent medical care. If ingestion is recent, gastric lavage or activated charcoal may limit absorption, performed under professional supervision. Intravenous fluids restore hydration and blood pressure, while electrolyte replacement corrects imbalances like potassium or sodium deficits. Continuous monitoring of heart rhythm and kidney function stabilizes the patient until recovery, focusing on reversing the excessive diuresis swiftly. Supportive care ensures circulatory and metabolic stability.

Drug Interactions

Effects on Other Medications

This drug can influence the performance of various medications when used concurrently. It may enhance the hypotensive effects of antihypertensives, risking excessive pressure drops, so dose adjustments are often necessary. Nonsteroidal anti-inflammatory drugs could reduce its diuretic efficacy and increase renal strain, a concern in prolonged use. Aminoglycosides or cisplatin heighten ototoxicity risks when combined, requiring auditory monitoring. It may increase lithium levels by reducing clearance, necessitating plasma checks. Digoxin toxicity risks rise with hypokalemia, demanding careful cardiac oversight. Adjustments minimize these interactions effectively.

Compatibility with Alcohol and Food

Alcohol consumption may worsen dehydration or hypotension, increasing dizziness risks, so moderation is advised. Food does not significantly alter oral absorption, though high-sodium diets might counteract fluid reduction, suggesting dietary balance. Potassium-rich foods like bananas can help offset potassium loss but require monitoring to avoid overcorrection.

Special Precautions

Use During Pregnancy and Breastfeeding

Lasix is generally avoided in pregnancy unless essential, as it crosses the placenta and may affect fetal fluid balance or growth, based on limited human data. It appears in breast milk, potentially altering infant electrolyte levels, so nursing mothers should consult their physician, possibly opting for alternatives to minimize exposure.

Impact on Driving and Machinery Operation

Dizziness or fatigue, particularly at initiation or dose changes, may impair driving or machinery operation. Patients should assess their tolerance before engaging in such activities, ensuring safety for themselves and others.

Considerations for Elderly and Pediatric Populations

Elderly individuals may require lower initial doses due to age-related renal decline, with monitoring for dehydration or electrolyte shifts. In children, its use is tailored to conditions like edema, with weight-based dosing adjusted cautiously under specialist guidance to avoid growth impacts. Personalized care ensures optimal safety and efficacy across these groups.