Furosemide

BRAND NAMES

Furosemide is marketed under several brand names, most commonly Lasix, but also Frumil, Frusemide, and Diusemide in different regions. These brands all contain the same active ingredient with similar therapeutic effects. They are available in tablets, oral solutions, and injectable forms based on treatment needs. The brand used may depend on regional preferences or hospital formularies. Regardless of labeling, the clinical action remains the same.

MECHANISM OF ACTION

Furosemide works by inhibiting the Na⁺-K⁺-2Cl⁻ cotransporter in the thick ascending limb of the loop of Henle in the kidney. This inhibition prevents reabsorption of sodium and chloride, leading to a strong diuretic effect. Increased urinary excretion reduces fluid overload and venous pressure. The drug also causes loss of potassium, calcium, and magnesium. Overall, it rapidly decreases edema and reduces blood pressure.

PHARMACOKINETICS:

Absorption
Absorption is the process by which a drug enters the bloodstream from the site of administration. It depends on factors like route of administration, drug form, and blood flow.

Distribution
Distribution refers to how the drug is transported by the blood to different tissues and organs. It is influenced by blood circulation, tissue binding, and plasma protein binding.

Metabolism
Metabolism is the chemical alteration of a drug in the body, mainly occurring in the liver. This process usually converts drugs into more water-soluble forms for easier removal.

Excretion
Excretion is the removal of drugs and their metabolites from the body. It mainly occurs through the kidneys in urine, but can also happen via bile, sweat, or lungs.

PHARMACODYNAMICS

Furosemide produces strong diuresis, leading to rapid elimination of excess fluid from the body. This results in decreased blood volume, reduced edema, and lower pressure in both systemic and pulmonary circulations. It has a quick onset, especially when given intravenously, making it useful for emergency management. Its effects on electrolytes, especially potassium, require careful monitoring. The overall response depends on dose and patient physiology.

ADMINISTRATION

Furosemide may be given orally or intravenously depending on the clinical situation. Oral administration is preferred for long-term management of conditions like hypertension and chronic edema. Intravenous use is reserved for urgent cases such as acute pulmonary edema where rapid action is required. Doses are often given in the morning to avoid nighttime urination. Proper administration requires monitoring of hydration and electrolyte status.

DOSAGE AND STRENGTH

Furosemide is commonly available in strengths such as 20 mg, 40 mg, and 80 mg tablets. Liquid and injectable preparations provide alternative options for patients unable to take tablets or needing rapid effect. The dosage varies widely depending on the underlying condition, patient age, and kidney function. Doctors may increase or decrease the dose based on response. Self-adjusting the dose is unsafe and should be avoided.

DRUG INTERACTIONS

Furosemide interacts with many medications, often enhancing the risk of dehydration or electrolyte imbalance. Combining it with other diuretics can intensify fluid loss. NSAIDs may reduce its diuretic effect by decreasing renal blood flow. Aminoglycoside antibiotics can increase the risk of hearing problems when used with furosemide. It can also raise lithium levels, making toxicity more likely.

FOOD INTERACTIONS

Although food may slightly delay absorption, it does not significantly reduce furosemide’s overall effect. A high-salt diet can counteract its diuretic action by promoting fluid retention. Alcohol may worsen dehydration and dizziness when taken with this medication. Caffeine can enhance diuresis, leading to increased fluid loss. Patients often need to monitor potassium-rich foods to avoid imbalances.

CONTRAINDICATIONS

Furosemide should not be used in patients with anuria, where no urine is produced. It is also contraindicated in individuals with severe electrolyte depletion such as hypokalemia or hyponatremia. People allergic to sulfonamides may react adversely to furosemide. It must be used cautiously in patients with hepatic coma due to risk of worsening symptoms. Proper medical evaluation is essential before starting therapy.

SIDE EFFECTS

Here are the rephrased versions:

• Headache → Pain or pressure in the head

• Nausea or vomiting → Feeling sick to the stomach or throwing up

• Diarrhea or constipation → Loose stools or difficulty passing stools

• Muscle cramps or spasms → Sudden tightening or aching of muscles

• Blurred vision → Difficulty seeing clearly

OVER DOSE

An overdose of furosemide can lead to severe dehydration and dangerous shifts in electrolytes. Symptoms may include extreme weakness, confusion, fainting, and rapid heartbeat. Overdose can also cause very low blood pressure and kidney stress. Immediate medical care is required to correct fluid and electrolyte abnormalities. Treatment typically includes IV fluids and close monitoring in a clinical setting.

TOXICITY

Toxicity from furosemide usually results from excessive doses or prolonged use without monitoring. It may cause severe potassium and sodium depletion, leading to muscle weakness and arrhythmias. Ototoxicity, or temporary hearing loss, can occur with high IV doses or interactions with certain antibiotics. Kidney function may worsen in dehydrated patients. Regular monitoring of electrolytes and renal function helps prevent toxicity.