Medication: Spironolactone

Your dog has been prescribed the active ingredient spironolactone to treat congestive heart failure due to mitral valve disease.

Key points:
• Aldosterone antagonist.
• Do not use in breeding, pregnant, or lactating dogs.
• Do not use in dogs with hypoadrenocorticism, hyperkalaemia or hyponatraemia.
• Use with caution in dogs with kidney or liver dysfunction.
• Dosage: once a day with food.

This information sheet is designed to help answer commonly asked questions and help you give the medication safely and effectively to your pet. It does not contain all available information for this medication. If you have other questions or need more information, contact your vet or pharmacist.Always follow the dosing instructions provided by your vet. 

Name

• Spironolactone (spir-ono-lac-tone).

Brand name

• Cardalis® (Europe & UK, US).
• Prilactone® (Europe & UK, US).
• Tempora® (US).
• Aldactone® (US).
• CaroSpir® (US).

Class of drug

• Aldosterone antagonist.

Storage

• Do not store above 25°C.
• Store in a dry place.

Your vet has prescribed spironolactone for the management of congestive heart failure (CHF) due to mitral valve disease (MVD). Aldosterone, a hormone that maintains sodium levels in the kidneys, is increased in dogs with CHF and spironolactone acts by preventing its harmful effects.

Spironolactone is given orally as flavored, chewable tablets once a day (with food). It is also available in tablets combined with  benazepril. Any part-used tablets should be stored in its opened blister pack and used within 72 hours.

Spironolactone may be given alongside other drugs used to treat CHF, eg furosemide and ACE inhibitors.

Side-effects are usually mild and can include vomiting and diarrhea. Hyponatremia (low sodium levels) and hyperkalemia (high potassium levels) can occur. Reversible prostatic atrophy may be observed in entire male dogs.

When combined with NSAIDs, there is a risk of kidney dysfunction. Use with digoxin may lead to increased plasma digoxin concentration.

Your dog will likely be on spironolactone for the rest of their life if responding well to treatment.

Dispose of any unused spironolactone safely – do not flush down the toilet or sink. Ask your veterinary team if they take back medication for disposal. Do not save for future use or give to other pets.

If you miss a dose, give the dose as soon as possible but do not double up a dose. Make sure the dose given doesn’t exceed the total recommended amount in any 24-hour period.

If your pet is unwell, contact your vet for advice.

Spironolactone should only be given to the dog that it has been prescribed for:

• Do not give to other pets in the household
• Do not give to breeding, pregnant or lactating dogs
• Do not give to dogs with hypoadrenocorticism, hyperkalaemia or hyponatraemia
• Use with caution in dogs with kidney or liver dysfunction
• If accidentally given to other pets, contact your vet for advice.

If accidentally eaten by a human, speak to your primary care doctor or poison control center.

Your vet will monitor that the medication is working and will check kidney and electrolyte levels prior to treatment and every 2 months.

Further information

If you have any concerns, further information on spironolactone can be found on the package insert and the following websites:

Europe & UK

• European Medicines Agency Cardalis® tablets for dogs (spironolactone with benzapril): ec.europa.eu/health/documents/community-register/2012/20120723123518/anx_123518_en.pdf.
• Veterinary Medicines Directorate Prilactone Next®: www.vmd.defra.gov.uk/productinformationdatabase/files/SPC_Documents/SPC_393150.PDF
• NOAH Compendium Cardalis® chewable tablets for dogs: www.noahcompendium.co.uk/?id=-472940
• NOAH Compendium Prilactone Next® 10, 50 and 100 mg chewable tablets: www.noahcompendium.co.uk/?id=-466503