Prilactone for dogs



Active ingredient



Diuretic / Heart

What is Prilactone?

Prilactone is a brand name for a drug with the active ingredient spironolactone. It is prescribed to dogs with congestive heart failure, a condition where the heart struggles to pump blood effectively. Prilactone is a diuretic, a type of drug that helps to remove excess fluid from the bloodstream through urine. This reduces the heart’s workload, as the heart does not have to pump the excess fluid around the body. Prilactone may also reduce the formation of scar tissue (fibrosis) in the heart. This may slow the progression of heart failure.

What does Prilactone do?

Prilactone reduces the heart’s workload in dogs with congestive heart failure. Spironolactone, the active ingredient in Prilactone, is a diuretic. This means that it promotes the removal of excess fluid from the bloodstream through urination. Prilactone does this by blocking the action of aldosterone, a hormone in the body.

Normally, the kidneys remove waste and excess water from the bloodstream to produce urine. Aldosterone reabsorbs water from the kidneys into the bloodstream, which increases blood volume. In dogs with congestive heart failure, the heart is unable to pump all of the excessive fluid in the bloodstream. This excessive fluid leaks into other organs (e.g. the lungs) and causes problems like breathing difficulties.
By blocking aldosterone’s effects, Prilactone helps to remove excess fluids from the bloodstream through urine. This reduces the heart’s workload and alleviates issues such as coughing and breathing difficulty. In this way, the pet’s overall quality of life is increased.
Prilactone may also reduce the formation of scar tissue in the heart. As scar tissue stiffens the heart’s walls and reduces its ability to pump blood, Prilactone helps to maintain heart function.

What is Prilactone for?

Prilactone is used for the following conditions in dogs:

Congestive Heart Failure (CHF): Prilactone is a diuretic commonly prescribed to dogs with congestive heart failure. Congestive heart failure in dogs can occur for various reasons (e.g. valve disease, diseased heart muscle). Prilactone reduces the heart’s workload and alleviates issues such as coughing and breathing difficulty.

Prilactone is often prescribed together with other drugs for dogs with congestive heart failure.

What are the possible side effects with Prilactone?

While generally well-tolerated, Prilactone – like all other drugs – may have side effects. It’s important for pet owners to be aware of these possible reactions. Side effects include:

Excessive Thirst and Urination: Dogs may experience an increase in thirst and urination due to the diuretic effect of Prilactone.

Electrolyte Imbalance: Electrolytes are important minerals in the body. In order for the body to function properly, electrolytes have to be at adequate and proportional levels. Prilactone  can lead to imbalances in electrolytes such as potassium. It is recommended to monitor electrolyte levels before starting Prilactone, and during treatment.

Reduced Appetite: Some dogs may experience a temporary decrease in appetite while on Prilactone.

Vomiting or Diarrhoea: Gut upset may occur in some dogs. Signs of gut upset include vomiting and/or diarrhoea.

Lethargy: A mild and transient lethargy or tiredness may be observed in some dogs.

Increased Blood Urea Nitrogen (BUN) and  Creatinine Levels: Prilactone can affect kidney function. BUN and creatinine are markers of kidney function, and elevated values  may indicate kidney issues. Periodic monitoring of kidney function is recommended.

Allergic Reactions: While rare, allergic reactions may occur. Signs of an allergic reaction can include swelling, itching, redness or difficulty breathing.

Remember, not all pets will experience these side effects, and the benefits of using Prilactone often outweigh the risks. However, if you notice any concerning symptoms or changes in your pet’s behaviour or health while they are taking Prilactone, it’s important to contact your vet immediately. They can provide guidance and adjust the treatment plan if necessary to ensure your pet’s safety and well-being.

Whats pets is Prilactone not suitable for?

Generally speaking, Prilactone is not suitable for the following pets:

  • Dogs allergic to Prilactone or any of its ingredients
  • Dogs that are pregnant, lactating or intended for breeding
  • Growing dogs
  • Dogs with dehydration, kidney problems and liver problems
  • Dogs with electrolyte imbalances
  • Dogs with health conditions such as Cushing’s disease

The above pets are at a greater risk of side effects from Prilactone.

If your dog has any of the above issues and your vet prescribes Prilactone, your vet will discuss the risks involved and emphasise the importance of close monitoring.

How to give Prilactone safely

  • Follow vet instructions: Always use Prilactone exactly as your vet has prescribed. This includes the right dose and frequency. Never adjust the dose on your own, even if your dog or cat seems to be feeling better or worse. If you aren’t sure of the dose prescribed, please call your vet to confirm.
  • Give with or after food: It’s generally best to give Prilactone with a meal, as food increases the efficacy of Prilactone . You can either put it in your pet’s food or feed it directly into their mouth after they’ve eaten.
  • Check with your vet if giving anything else: Your vet should be aware of other drugs your pet is on, but it’s always worth double-checking in case there’s been a miscommunication somewhere. If your dog is on supplements or non-prescription treatments you should also tell your vet when they prescribe Prilactone, as they may not be suitable to be given together.
  • Storage and Handling: The tablet can be halved or quartered. Store Prilactone according to the instructions on the packaging, usually in a cool and dry place. Make sure it’s out of reach of children and other pets. Wash your hands after handling Prilactone. People who are allergic to spironolactone or any of Prilactone’s other ingredients should not handle this product.
  • Report any accidental overdose to your vet immediately: If you have mistakenly given too much Prilactone, report it to your vet as soon as you realise the error. They may recommend blood tests, intravenous fluids, and/or monitoring, depending on the severity of the overdose.

Prilactone FAQs

What are the benefits of spironolactone in dogs?

The benefits of spironolactone in dogs include reduced fluid buildup in the body and reduced workload on the heart. This provides relief from clinical signs such as coughing, lethargy and breathing difficulty, which can improve their quality of life and survival time.

What is a kidney sparing diuretic for dogs?

A kidney sparing diuretic for dogs is a diuretic that is meant to be safe for dogs with kidney issues. If your dog has kidney issues, it is still best for your vet to assess your dog and check their health status before starting your dog on any diuretic.

What are the side effects of aldactone in dogs?

Aldactone and Prilactone are different brand names for the drug spironolactone. The side effects of aldactone in dogs include excessive thirst and urination, vomiting, diarrhoea, reduced appetite, decreased activity, kidney damage, itching, swelling, difficulty breathing and so on. Contact your vet if you notice these side effects in your dog.

How does Prilactone help my dog’s heart condition?

Prilactone helps your dog’s heart condition by reducing excess fluid in the bloodstream. This reduces the heart’s workload in dogs with congestive heart failure, as the heart does not have to pump the excess fluid around the body.

Can my dog still take Prilactone if they are on other medications?

Your dog can still take Prilactone if they are on other medications. However, it also depends on what medications they are. If your dog is on certain medications (e.g. digoxin, NSAIDs), they need to be assessed (with vet visits and diagnostics) before starting on Prilactone, and they need to be closely monitored while on Prilactone.

Is Prilactone safe for long-term use?

Yes, Prilactone is safe for long-term use. A long-term study showed that dogs on certain heart medication (“standard therapy”) and Prilactone had longer survival times than dogs on “standard therapy” and a placebo.

Prilactone Datasheet

All drugs have a manufacturer’s datasheet, which gives information about the drug’s use and possible side effects. There is usually one in your Prilactone box, but if you have lost it you can click on the button below to be taken on an online version.

Courses related to Prilactone

Please note that the information contained herein is provided for informational purposes only. Although it has been written by a vet, we cannot consider the individual nature of your pet’s problems so it does not constitute veterinary advice. If you have questions about your pet’s medication or their health you should contact a vet, who will be able to help.