Suzanne & Darcy
Member Since 2020
Oh no. That is so horrible to hear. I am really sad that this is what they said. They didn’t have any help to offer? They didn’t suggest backing off on the dose of Lasix and adding in some Pimobendan? They had no ideas? How bad are his kidney numbers (BUN, Creatinine, urine specific gravity? Phosphorus?) You probably don’t want to talk about any of it right now and I understand. I will say that if it was caused by the Lasix after just a few days that this isn’t irreversible. I have known cats to improve once things are better managed and renal perfusion is restored (IV fluids or sub-q fluids at home) and other treatments including cardiac meds.
Since you like to research things. I am copying what a quick query to AI resulted in.
Yes—case reports and clinical experience indicate that kidney values (creatinine/BUN) that worsen after starting furosemide (Lasix) for congestive heart failure in cats can sometimes improve after reducing or stopping the drug, addressing dehydration, or optimizing cardiac management.
Key points and mechanisms:
Since you like to research things. I am copying what a quick query to AI resulted in.
Yes—case reports and clinical experience indicate that kidney values (creatinine/BUN) that worsen after starting furosemide (Lasix) for congestive heart failure in cats can sometimes improve after reducing or stopping the drug, addressing dehydration, or optimizing cardiac management.
Key points and mechanisms:
- Pre-renal azotemia: Diuretics can cause volume depletion, reducing renal perfusion and raising BUN/creatinine. This is often reversible with fluid resuscitation or reducing the diuretic dose.
- Cardiorenal interactions: Heart failure itself can cause poor renal perfusion; improving cardiac output or relieving congestion may improve renal function even while on diuretics. Conversely, excessive diuresis can worsen renal function.
- Dose dependency and reversibility: Worsening renal parameters after starting furosemide are frequently dose-dependent and may partially or fully reverse when the dose is lowered, frequency altered, or the drug discontinued—especially if the injury is functional (pre-renal) rather than intrinsic renal damage.
- Concurrent causes: Other contributors (NSAIDs, dehydration, hypotension, nephrotoxins, acute kidney injury) affect reversibility; intrinsic chronic kidney disease may not fully recover.
- Monitoring strategy: Frequent rechecks of BUN/creatinine, electrolytes, body weight, urine output, and hydration after any diuretic change are recommended. Consider adjusting diuretic dose, adding/resting with IV or SC fluids, and optimizing heart-failure therapy (ACE inhibitors, pimobendan where appropriate) under veterinary guidance.
- Veterinary cardiology and nephrology texts discuss pre-renal azotemia from diuretics and reversible creatinine increases.
- Case reports and clinical studies in dogs and cats document reversible azotemia with diuretic modification and fluid therapy.
- Guidelines for managing feline congestive heart failure advise careful titration of diuretics with monitoring of renal values.
- Contact your veterinarian promptly if creatinine/BUN rise after starting Lasix.
- Vet may assess hydration, blood pressure, electrolytes, urinalysis, and consider stopping/reducing furosemide or giving short-term fluids (SC/IV).
- Recheck renal values within 24–72 hours and again in 1–2 weeks after any change.
- Balance heart failure control versus renal function—small dose adjustments or alternate diuretic strategies may be used.
- If intrinsic kidney disease is present, prognosis for full recovery is lower; aim for stabilization and symptom control.