Amiloride
Amiloride hydrochloride
Also known as: Amilamont · Moduretic · Co-amilozide · Co-amilofruse · Frumil LS · Amiloride hydrochloride · Amiloridum
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Dosing by species
Dosing data for this drug is not yet available in the VetSheet formulary. Every other section below is complete. Consult the current product label before prescribing.
Overview
Amiloride is a potassium-sparing diuretic that is typically used in combination with other, more potent diuretics (such as furosemide or thiazides) to manage edema and ascites while preventing excessive potassium loss. Because it is a weak diuretic when used alone, its primary clinical value lies in its ability to mitigate the hypokalemia often caused by loop diuretics.
Clinical Warning: Can cause life-threatening hyperkalemia if used inappropriately, especially in patients with renal impairment or those receiving ACE inhibitors.
Clinical Pearl: Often formulated as a compound preparation (e.g., co-amilofruse) to balance potassium excretion and retention in chronic heart failure management.
Mechanism of action
Amiloride acts directly on the distal convoluted tubule and collecting duct of the nephron.
It blocks epithelial sodium channels (ENaC) → inhibits sodium absorption → decreases the electrical potential across the tubular epithelium → reduces the driving force for potassium and hydrogen ion secretion.
This leads to a failure of the normal renal concentration gradient, resulting in sodium loss (mild diuresis) and potassium retention.
Safety & warnings
Contraindications
- Hyperkalemia
- Severe renal impairment or anuria
- Addison's disease (hypoadrenocorticism)
- Concurrent use of potassium supplements (unless closely monitored)
Adverse effects
- Hyperkalemia
- Hyponatremia
- Gastrointestinal disturbances (nausea, vomiting, diarrhea)
- Dehydration
- Weakness or lethargy
Precautions
Use with extreme caution in patients with renal dysfunction or diabetes mellitus. Regular monitoring of serum electrolytes (especially potassium and sodium) and renal function (BUN, creatinine) is essential. > Do not use in patients with pre-existing hyperkalemia.
Drug interactions
Increased risk of severe hyperkalemia due to additive potassium-sparing effects.
Significant risk of hyperkalemia.
May reduce the diuretic effect of amiloride and increase the risk of nephrotoxicity and hyperkalemia.
Additive potassium-sparing effects leading to hyperkalemia.
Monitoring
- Serum potassium levels
- Serum sodium levels
- Renal function panel (BUN, Creatinine)
- Hydration status
- Blood pressure
Pharmacokinetics
Half-life
Absorption
Incompletely absorbed from the gastrointestinal tract (approximately 50% in humans).
Distribution
Widely distributed; does not highly bind to plasma proteins.
Metabolism
Not significantly metabolized in the liver.
Elimination
Excreted unchanged primarily in the urine, with a smaller portion excreted in feces.
Overdose
Overdose primarily presents as severe hyperkalemia, dehydration, and hyponatremia. Clinical signs may include profound weakness, bradycardia, cardiac arrhythmias, and collapse.
Treatment: Discontinue the drug immediately. Induce emesis or perform gastric lavage if ingestion is recent. Treat hyperkalemia aggressively (e.g., IV fluids, calcium gluconate, dextrose/insulin, or sodium bicarbonate as clinically indicated).
Available products
Formulations
- 5 mg oral tablets
- 1 mg/ml oral solution
- Compound preparations with hydrochlorothiazide (Co-amilozide)
- Compound preparations with furosemide (Co-amilofruse)
Human-labeled
- Amilamont (1 mg/ml oral solution)
- Moduret (Amiloride/Hydrochlorothiazide)
- Moduretic (Amiloride/Hydrochlorothiazide)
- Co-amilozide (Amiloride/Hydrochlorothiazide)
- Co-amilofruse (Amiloride/Furosemide)
- Frumil (Amiloride/Furosemide)
- Frumil LS (Amiloride/Furosemide)
Regulatory status
POM (Prescription Only Medicine). Often used as human-authorized products under the cascade.
POM (Prescription Only Medicine). Human preparations used under the prescribing cascade.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store at room temperature in a tightly closed container. Protect from light and moisture.
Client information
Amiloride is a 'water pill' (diuretic) that helps your pet's body get rid of extra fluid while preventing the loss of potassium. It is usually prescribed alongside other medications for heart or liver conditions.
- Water access: Always provide your pet with plenty of fresh drinking water.
- Diet: Do not give your pet potassium supplements or salt substitutes unless specifically directed by your veterinarian.
- Watch for: Contact your vet if your pet becomes extremely lethargic, weak, loses their appetite, or experiences vomiting/diarrhea.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.