Furosemide

Furosemide Medication Overview

Furosemide, commonly known by the brand name Lasix, is a potent diuretic medication belonging to the class of drugs called loop diuretics. Its primary use is to treat fluid retention (edema) and swelling caused by congestive heart failure, liver disease, kidney disease, or other medical conditions. Furosemide works by preventing your body from absorbing too much salt, allowing the salt to instead be passed in your urine.

Pharmacological Profile

Furosemide inhibits the symporter of sodium, potassium, and chloride (Na+/K+/2Cl-) in the thick ascending limb of the loop of Henle. This inhibition leads to an increased excretion of sodium, chloride, and water into the renal tubules, diminishing fluid in the tissues and blood vessels. Furosemide also exerts venodilatory effects, which contribute to its rapid onset in reducing pulmonary edema.

Indications for Use

Furosemide is indicated for the management of edema associated with congestive heart failure, cirrhosis of the liver, and renal disease, including nephrotic syndrome. It is also prescribed for the treatment of hypertension (high blood pressure) alone or in combination with other antihypertensive agents.

Administration and Dosage

Furosemide is available in tablet and liquid forms and can also be administered intravenously or intramuscularly. Dosage varies based on patient’s age, weight, condition being treated, and response to treatment. Initial dosing is typically conservative to assess response, with subsequent adjustments as needed. Chronic therapy necessitates periodic assessment of electrolyte balance and kidney function.

Specific Dosage Considerations

Individual dosing is crucial for Furosemide due to wide interpatient variability. Renal impairment may require dosage adjustments. In heart failure patients, doses may be titrated upwards while monitoring for signs of over diuresis. For hypertension, Furosemide is often part of a multi-drug regimen. Pediatric and geriatric populations necessitate careful dose selection and titration.

Interactions with Other Medications

Furosemide may interact with a wide array of medications such as aminoglycoside antibiotics, leading to increased risk of hearing damage, and nonsteroidal anti-inflammatory drugs (NSAIDs), which can decrease its diuretic effect. Concomitant use of high-dose aspirin with Furosemide may result in high blood levels of aspirin and aspirin toxicity. Furosemide can potentiate the effects of other antihypertensive drugs and may also affect blood glucose levels, necessitating adjustment of anti-diabetic medications.

Electrolyte and Metabolic Abnormalities

Furosemide therapy can lead to significant alterations in electrolyte levels including hyponatremia, hypokalemia, hypomagnesemia, and hypochloremia, as well as metabolic alkalosis. Regular monitoring of serum electrolytes is essential, and supplementation of potassium or magnesium may be necessary. Dietary intake should also be managed to mitigate electrolyte imbalances.

Use in Renal and Hepatic Impairment

In patients with renal impairment, Furosemide’s effectiveness may be diminished, and accumulation of the drug can lead to increased risk of toxicity. Caution is advised, with careful dosing and monitoring of renal function. In patients with hepatic impairment, close monitoring is required due to the risk of hepatic encephalopathy, as Furosemide can induce changes in fluid status and electrolyte balance that may precipitate or exacerbate this condition.

Side Effects Profile

In some patients, Furosemide may provoke side effects, which include, but are not limited to, dehydration, electrolyte imbalances, hypotension, ototoxicity (particularly with rapid IV administration), gout flares, and gastrointestinal symptoms such as nausea and vomiting. Allergic reactions to Furosemide may occur, and the drug contains sulfonamide, which could provoke reactions in those allergic to sulfa drugs.

Monitoring and Follow-Up

Patients on Furosemide require regular monitoring including clinical evaluation for fluid status, renal function tests, and serum electrolytes. Periodic blood work is recommended to detect possible anemia or liver damage. If possible, blood pressure and weight should be recorded routinely to monitor drug efficacy and onset of potential complications.

Pregnancy and Lactation Considerations

Furosemide is classified as a pregnancy category C drug, meaning risk to the fetus cannot be ruled out. Furosemide should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Furosemide passes into breast milk and may inhibit lactation; a decision should be made whether to discontinue the drug or to discontinue nursing.

Storage and Handling Instructions

Furosemide should be stored at room temperature, between 15-30 degrees Celsius (59-86 degrees Fahrenheit), away from light and moisture. Oral solution formulation must be kept from freezing and should be discarded 90 days after opening. Tablets should be stored in a closed container and handled with dry hands.

Overdose Management

An overdose of Furosemide may lead to profound diuresis with water and electrolyte depletion. In case of overdose, supportive and symptomatic treatment should be initiated, with a focus on fluid and electrolyte rebalance. In severe cases, monitoring in a hospital setting with IV rehydration might be necessary. Dialysis does not efficiently remove Furosemide due to its high protein binding and the large volume of distribution.