Generic Furosemide

Introduction

Furosemide is a loop diuretic frequently prescribed to reduce excess fluid in the body. It belongs to the diuretics medication group and works by increasing urine output, which helps control conditions such as heart failure, hypertension, and renal disease. In Hong Kong, clinicians use furosemide to manage acute and chronic fluid overload, often in hospital settings and community practice. The active compound is furosemide, and the medication is available both as a generic product and under several well‑known brand names.

What is Furosemide?

Furosemide is the generic version of the original brand Lasix, and it is also marketed under names such as Frusemide and Uremax in various regions. All formulations contain the same active compound, furosemide, which delivers the therapeutic effect of loop diuretic action. Our online pharmacy provides this generic alternative as a cost‑effective treatment option, offering the same pharmacological profile as the brand‑named products.

Furosemide is classified as a loop diuretic. It was first synthesized in the early 196s by scientists at Hoechst AG (now part of Sanofi) and subsequently approved for medical use worldwide. The medication is supplied as oral tablets (typically 20 mg, 40 mg, and 80 mg) and as injectable solutions for hospital administration.

How Furosemide Works

Furosemide inhibits the Na⁺‑K⁺‑2Cl⁻ cotransporter located in the thick ascending limb of the loop of Henle, a key segment of the nephron responsible for reabsorbing about 25 % of filtered sodium. By blocking this transporter, the drug prevents sodium, chloride, and potassium from being reabsorbed, creating an osmotic gradient that retains water in the tubular lumen. The resultant increase in urinary volume leads to a rapid reduction in extracellular fluid volume.

Onset of diuretic action occurs within 30 minutes after oral administration and 5 minutes after intravenous injection. The peak effect appears 1–2 hours post‑dose, and the diuretic response lasts approximately 6–8 hours. Furosemide is primarily eliminated unchanged by the kidneys; a smaller fraction undergoes hepatic metabolism. Renal clearance correlates with glomerular filtration rate, making dose adjustments necessary in patients with impaired kidney function.

Conditions Treated with Furosemide

• Congestive Heart Failure (CHF) – Fluid accumulation in the lungs and peripheral tissues contributes to dyspnoea and reduced exercise capacity. Furosemide relieves pulmonary and systemic congestion, improving symptom control and quality of life. In Hong Kong, heart failure prevalence is estimated at 1–2 % of the adult population, with a growing elderly cohort requiring effective diuresis.

• Hypertension (HTN) – While not a first‑line antihypertensive, furosemide can be added when volume overload contributes to elevated blood pressure, especially in resistant hypertension.

• Chronic Kidney Disease (CKD) with Edema – Patients with CKD often develop peripheral oedema and ascites; loop diuretics overcome the diminished nephron function to promote fluid excretion.

• Acute Pulmonary Oedema – Rapid intravenous furosemide reduces intravascular volume, lowering pulmonary capillary pressure and relieving breathlessness.

• Cirrhosis‑related Ascites – In liver disease, portal hypertension leads to fluid accumulation in the abdomen; furosemide combined with spironolactone is a standard regimen.

• Hypercalcaemia – By increasing calcium excretion, furosemide assists in managing severe elevations of serum calcium, often as adjunct therapy.

Suitable Candidates for Furosemide Treatment

Furosemide is appropriate for adults who demonstrate clinically significant fluid overload or volume‑dependent hypertension. Typical candidates include:

• Patients with symptomatic heart failure (NYHA class II–IV) who have persistent peripheral or pulmonary oedema despite optimal guideline‑directed therapy.
• Individuals with resistant hypertension where volume expansion is a contributing factor.
• CKD stage 3–5 patients with refractory oedema not adequately controlled by thiazide diuret.
• Cirrhotic patients with moderate to severe ascites requiring diuretic therapy.

Contra‑indications or cautionary situations include:

• Anuria or severe renal impairment (eGFR < 15 mL/min/1.73 m²) where diuretic response is minimal.
• Known hypersensitivity to furosemide or any excipients.
• Active electrolyte disturbances (severe hypokalaemia, hyponatraemia) that could be exacerbated by further losses.
• Pregnancy and lactation: furosemide crosses the placenta and is secreted in breast milk; use only when clearly indicated.

Risks, Side Effects, and Interactions

Common

• Electrolyte imbalance – hypokalaemia, hyponatraemia, hypomagnesaemia.
• Dehydration – excessive urine output leading to reduced intravascular volume.
• Dizziness or orthostatic hypotension – due to volume depletion.
• Increased uric acid – may precipitate gout attacks.

Rare

• Hyperuricaemia – persistent elevation of serum uric acid.
• Otitis media – reported with high‑dose intravenous therapy.
• Photosensitivity – unusual skin reactions to sunlight exposure.

Serious

• Severe electrolyte disturbances – particularly profound hypokalaemia that can cause cardiac arrhythmias.
• Acute kidney injury (AKI) – abrupt rise in serum creatinine when diuresis exceeds renal perfusion.
• Hearing loss (ototoxicity) – especially with rapid high‑dose IV administration or concurrent aminoglycoside use.
• Allergic reactions – anaphylaxis, Stevens‑Johnson syndrome (extremely rare).

Clinically Relevant Drug–Drug Interactions

• NSAIDs – reduce renal prostaglandin synthesis, diminishing furosemide’s diuretic effect.
• ACE inhibitors/ARBs – synergistic effect on potassium; monitor for hyperkalaemia.
• Digoxin – hypokalaemia potentiates digoxin toxicity; electrolytes must be checked frequently.
• Lithium – increased lithium reabsorption may raise serum levels, risking toxicity.
• Aminoglycoside antibiotics – combined use heightens risk of ototoxicity.

Patients should disclose all current medications, including over‑the‑counter products and herbal supplements, to their healthcare professional.

Practical Use: Dosing, Missed Dose, Overdose

• Standard oral dosing – For most adult indications, the usual starting dose is 40 mg once daily, titrated up to 80 mg twice daily based on response and renal function.
• Intravenous administration – In acute settings, a 20–40 mg IV bolus may be given, followed by repeat dosing or continuous infusion as required.
• Renal adjustment – When eGFR falls below 30 mL/min/1.73 m², the dose is often reduced to 20 mg once daily or given every other day.

Missed dose – If a dose is forgotten and the next scheduled dose is still several hours away, take the missed dose. If it is close to the time of the next dose, skip the missed one and continue the regular schedule. Do not double‑dose.

Overdose – Symptoms may include severe dehydration, hypotension, electrolyte abnormalities, and renal failure. Immediate medical attention is required. Treatment focuses on fluid replacement, electrolyte correction, and supportive care; dialysis may be necessary in extreme cases.

Precautions –

• Avoid excessive alcohol, which can amplify hypotensive effects.
• Take furosemide with a full glass of water; food does not markedly affect absorption but a light snack may reduce gastric irritation.
• Regular monitoring of weight, blood pressure, renal function, and electrolytes is essential, especially during dose titration.

Buying Furosemide from Our Online Pharmacy

Patients in Hong Kong can purchase furosemide safely through our online pharmacy. Key advantages include:

• Affordable pricing – We source generic furosemide at near‑manufacturer cost, passing the savings directly to you.
• Verified quality – All batches are procured from licensed overseas suppliers that meet international Good Manufacturing Practice (GMP) standards.
• Guaranteed delivery – Discreet packaging, with express shipping typically within 7 days and regular airmail arriving in approximately 3 weeks.
• Online‑only access – Our pharmacy broker service collaborates with licensed overseas pharmacies, enabling a confidential supply chain that respects patient privacy.

This service is particularly valuable for individuals who encounter limited stock, high out‑of‑pocket costs, or insurance restrictions in local pharmacies.

FAQ

• Is Furosemide available in both brand‑name and generic forms in Hong Kong?
  Yes. The original brand‑name product is Lasix, while numerous generic manufacturers supply the same active compound, furosemide, at lower cost.

• What storage conditions are recommended for furosemide tablets?
  Store tablets at room temperature (15‑30 °C), protected from moisture, direct sunlight, and heat. Do not refrigerate; keep the container tightly closed.

• Can furosemide be taken with a high‑protein diet?
  A high‑protein diet does not interfere with furosemide’s absorption, but protein‑rich meals may increase urinary calcium excretion, which should be monitored in patients with kidney stones.

• How does altitude affect furosemide’s diuretic action?
  Higher altitude can cause mild diuresis independent of medication; combining this effect with furosemide may increase fluid loss, so hydration status should be closely observed when traveling to mountainous regions.

• Do different regions use different inactive ingredients in furosemide tablets?
  Yes. Some Asian formulations contain lactose or starch as fillers, whereas European versions may use microcrystalline cellulose. Patients with specific excipient allergies should review the product label.

• Is furosemide detectable on standard drug‑screening tests?
  Routine employment or sports drug screens do not target furosemide, but specialized anti‑doping assays can detect loop diuretics due to their potential for masking other substances.

• What historical trial established furosemide’s efficacy in heart failure?
  The pivotal ESCAPE trial (2005) demonstrated that high‑dose intravenous furosemide reduced pulmonary congestion and improved symptom scores in acute decompensated heart failure, supporting its continued use in modern guidelines.

• Can furosemide be used to treat hypertension in patients without fluid overload?
  Although effective, it is not preferred for isolated hypertension because of its risk of electrolyte disturbances; thiazide‑type diuretics are typically chosen first.

• How does furosemide interact with herbal supplements such as ginseng?
  Ginseng may potentiate the hypotensive effect of furosemide, leading to an increased risk of dizziness or fainting. Patients should discuss any supplement use with their clinician.

• Are there any special import regulations for personal use of furosemide in Hong Kong?
  Hong Kong permits individuals to import a 30‑day supply of prescription medicines for personal use, provided they retain a valid prescription and the medication complies with local safety standards.

Glossary

Loop Diuretic

A class of drugs that act on the ascending loop of Henle to inhibit sodium, potassium, and chloride reabsorption, producing a powerful diuretic effect.

Electrolyte Imbalance

A disturbance in the normal concentrations of ions such as sodium, potassium, or magnesium in the blood, which can affect heart rhythm, muscle function, and overall fluid balance.

eGFR (Estimated Glomerular Filtration Rate)

A calculated measure of kidney function that reflects how well the kidneys filter blood; used to guide dosing adjustments for renally cleared drugs.

Ototoxicity

Damage to the inner ear caused by certain medications, leading to hearing loss or ringing in the ears (tinnitus).

⚠️ Disclaimer

The information provided about Furosemide is for general knowledge only. It does not replace professional medical consultation. All treatment decisions should be made under the supervision of a qualified healthcare provider. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to Furosemide for individuals who may have limited availability through traditional pharmacies, prescription‑based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication.