Heart Medications

Heart Medications

Author: Katt

ATTENTION: The following information is strictly an educational reference. You should never start your ferret on any medication, or change the dosing of a prescribed medication, before consulting with your veterinarian.

Please also note that the following is NOT a comprehensive list of medications, but rather a review of some of the more commonly used medications.

Furosemide (Lasix)

Furosemide is often one of the first medications that a ferret will be started on when diagnosed with heart failure. Furosemide is a loop diuretic (referred to by some as a “water pill”). Diuretics work by removing fluid from the body. They stimulate the kidneys to remove more water from the blood as it is filtered; as the blood’s water content decreases, water is drawn from the tissues (lungs, abdomen, etc) back into the bloodstream, where it can then be further filtered by the kidneys and excreted as urine. Removing the excess fluid helps to relieve symptoms such as cough and abdominal distension.

Diuretics lower the total water content of the blood, which also lowers the blood volume (called intravascular volume). Doing this reduces the pressure in the arteries that the heart has to pump against. You can think of it as pushing a box filled with books across the floor (the heart pumping blood before diuretics), compared to pushing an empty cardboard box across the floor (the heart pumping blood after diuretics). This not only potentially relieves a significant amount of strain on the heart*, but also allows the heart to pump (“push”) the blood through the body much more effectively – bringing oxygen and nutrient rich blood to vital organs and relieving some of the symptoms of heart disease.

  • Starting Dose: 0.25-1.0 mg/kg every 12-24 hours (1-2x daily)
  • Typical Dose Range: 1-4mg/kg every 8-12 hours (2-3x daily)
  • Maximum Dose: 4mg/kg every 8 hours (3x daily) = 12mg/kg total per day Max

*Note: while furosemide should theoretically reduce strain on the heart, extensive studies on humans have shown that it may not reduce strain. It IS however extremely helpful in treating symptoms and improving quality of life in patients with heart failure.

 

Enalapril (Vasotec, Renitec, Enacard)

Enalapril is often one of the first medications that a ferret will be started on when diagnosed with heart failure. Enalapril is in the medication class known as ACE-Inhibitors (Angiotensin Converting Enzyme Inhibitors), often abbreviated as ACE-I’s. These medications work by inhibiting ACE, a hormone involved in a pathway known as the RAAS (Renin-Angiotensin-Aldosterone System), which helps to control blood pressure. ACE-Inhibitors help to relax blood vessels throughout the body, resulting in a lower blood pressure (this effect is called vasodilation). This means that the heart has to do far less work to pump blood through the body, as it has to pump against that pressure. Using the same box analogy above, this is like pushing a lightweight box instead of a heavy box across the floor. This not only relieves a significant amount of strain on the heart, but also allows the heart to pump (“push”) the blood through the body much more effectively – bringing oxygen and nutrient rich blood to vital organs and relieving some of the symptoms of heart disease.

ACE-Inhibitors have been shown to have significant mortality benefit in humans, and potentially in dogs. Enalapril has also been shown by some studies to delay the onset of heart failure in dogs with heart disease. Its mortality benefit has not yet been studied in ferrets.

  • Starting Dose: 0.5mg/kg every 48 hours (every other day) and titrate up
  • Typical Dose Range: 0.25-0.5mg/kg every 12-24-48 hours (1-2x daily, or every other day)
  • Maximum Dose: 0.5mg/kg every 12 hours (2x daily) = 1mg/kg total per day Max

 

Benazepril (Fortekor)

Benazepril is another medication in the ACE-Inhibitor class that is used more often by vets outside of the US. It works in the same way as Enalapril (see above for mechanism).

  • Dose: 0.25–0.5 mg/kg every 12–24 hours (1-2x daily)

 

Pimobendan (Vetmedin)

Pimobendan is typically reserved for later in heart failure. Pimobendan is a vasodilator and inonotropic medication. Ionotropes are medications that helps the heart to contract, and thus pump, more strongly. Vasodilators relax the blood vessels, reducing the blood pressure that the heart must pump against (see Enalapril). Additionally, Pimobendan may have some neurohormonal and anti-inflammatory benefits in ferrets with heart disease. Pimobendan thus helps the heart to contract/pump better, as well as reliving the pressure it has to pump against (see box analogy under Furosemide and Enalapril), which overall allows the heart to pump (“push”) the blood through the body much more effectively – bringing oxygen and nutrient rich blood to vital organs and relieving some of the symptoms of heart disease.

Pimobendan has been shown to have significant mortality benefit in dogs. Its mortality benefit has not yet been studied in ferrets.

  • Staring Dose: 0.5 mg/kg every 12 hours (2x daily)
  • Typical Dose Range: 0.5–1.25 mg/kg every 12 hours (2x daily)
  • Maximum Dose: 1.25 mg/kg q12h = 2.5mg/kg total per day Max

 

Spironolactone

Spironolactone is an anti-aldosterone diuretic. Similar to furosemide, it helps to remove excess fluid from the body. Additionally, it may have some hormonal benefits that benefit the heart. Spironolactone is used in ferrets, but its use is far less common than the above medications. If your ferret’s symptoms (particularly symptoms due to fluid retention) are not well controlled on a combination of Furosemide, Enalapril or Benazepril, and Pimobendan, you may want to ask your vet about adding Spironolactone as an additional medical agent. If your vet is unfamiliar with its use in ferrets, they may wish to contact an exotics specialist at a nearby veterinary university. The Washington State University College of Veterinary Medicine is one such good contact.

Spironolactone has been shown to have significant mortality benefit in humans and in dogs. Its mortality benefit has not yet been studied in ferrets.

  • Dose: 1–2 mg/kg every 12 hours (2x daily)

 

Anti-arrhythmics

If your ferret has an electrical abnormality of the heart resulting in an abnormal heart rhythm (see types of Heart Disease), they may require treatment with an antiarrhythmic. There are many different types of arrhythmia, and an even larger variety of different antiarrhythmics. Details of the mechanism of each will not be discussed here, but we will mention a few antiarrhythmics that have been used in ferrets [Reference 7]:

  • Drugs that may be used to treat some types of tachyarrthymia (rapid heart rates) include: lidocaine, digoxin, diltiazem, beta-blockers (propranolol, atenolol). (7)
  • Drugs that may be used to treat some types of bradyarrthymia (slow heart rates) include: atropine, propanthelin (7)
  • Drugs that may be used to treat some types of heart block include: anticholinergics (propantheline), beta-adrenergics (e.g. terbutaline, isoproterenol) and phosphodiesterase inhibitors (aminophylline, theophylline). (7)

 

Heart Supplements: Taurine and Others

There are several different supplements that may benefit heart health, with varying amounts of data to support their use. Due to the wide variety of available supplements they will not be discussed in detail on this page. A few supplements of note:

Taurine: there have been several studies in several different species that indicate added taurine supplements may have a significant benefit on heart health in both healthy animals, and those with heart disease. Taurine is an essential nutrient for ferrets and cats – they must obtain it from their diet, as their bodies are unable to create it.

Hawthorn: some studies in humans have indicated that hawthorn may be helpful in treating heart disease. Few studies in animals have been conducted.

L-Carnitine: some studies in humans have indicated that L-Carnitine may be helpful in treating heart disease. Few studies in animals have been conducted.

CoQ10: some very limited studies in humans have indicated that CoQ10 might offer a slight benefit to patients in heart failure; further studies are needed for more conclusive data. Few studies in animals have been conducted.

 

 

 

 

 

 

 

 

References:

  1. Atkins, C., Keense, B., Brown, W., Coats, J., Crawford, M., et al. (2007). Results of the veterinary enalapril trial to prove reduction in onset of heart failure in dogs chronically treated with enalapril alone for compensated, naturally occurring mitral valve insufficiency. JAVMA. 23 (7): 1061-1069.
  2. Bernay, F., Bland, J., Haggstrom, J., Baduel, L., Combes. B., et al. (2010). Efficacy of spironolactone on survival in dogs with naturally occurring mitral regurgitation caused by myxomatous mitral valve disease. Journal of Veterinary Internal Medicine. 24:331–341.
  3. Bowles, D. Fry, D. (2011). Pimobendan and its use in treating canine congestive heart failure. Compendium: Continuing Education for Veterinarians. E1-E6.
  4. COVE Study Group. (1995). Controlled Clinical Evaluation of Enalapril in Dogs With Heart Failure: Results of the Cooperative Veterinary Enalapril Study Group. Journal of Veterinary Internal Medicine. 9 (4): 243-252.
  5. Gordon, S., Miller, M., Saunders, A. (2006). Pimobendan in Heart Failure Therapy – A Silver Bullet? Journal of the American Animal Hospital Association. 42: 90-93.
  6. Hofman-Bang,C., Rehnqvist, N., Swedberg, K., Wiklund, I., Astrom, H. (1995). Coenzyme Q10 as an adjunctive treatment of chronic congestive heart failure. Journal of Cardiac Failure. 1 (2): 101-107.
  7. Johnson-Delaney, C. (2017). Ferret Medicine and Surgery. Boca Raton, Fl: Taylor & Francis Group, LLC.
  8. Lango, R., Smolenski, R., Narkiewicz, M., Suchorzewska, J., Lysiak-Szydlowska, W. (2001). Influence of L-carnitine and its derivatives on myocardial metabolism and function in ischemic heart disease during cardiopulmonary bypass. Cardiovascular Research. 51: 21–29
  9. Lewington, J. (2007). Ferret Husbandry, Medicine, and Surgery, 2e. Philadelphia, PA: Elsevier.
  10. Oyama, M. (2009). Cardiac drugs for treatment of canine heart failure. NAVC Clinician’s Brief. 7: 56-59.
  11. Pittler, M., Schmidt, K., Ernst, E.Hawthorn Extract for Treating Chronic Heart Failure: Meta-analysis of Randomized Trials. The American Journal of Medicine. 114: 665-674.
  12. Quesenberry, K., Carpenter, J.  (2012). Ferrets, Rabbits and Rodents Clinical Medicine and Surgery, 3e. St. Louis, MO: Elsevier.
  13. Sander, S., Coleman, C., Patel, A., Kluger, J., White, M. (2006). The impact of coenzyme Q10 in patients with chronic heart failure. Journal of Cardiac Failure. 12 (6): 464-472.
  14. Sharma, A., Fonarow, G., Butler, J., Ezekowitz, J., Felker, M., (2016). Coenzyme Q10 and heart failure: A state-of-the-art review. Circ Heart Fail. 9 (4): 1-8.
  15. Struthers, A. (1999). Why does spironolactone improve mortality over and above  an ACE inhibitor in chronic heart failure? Br J Clin Pharmacol. 47: 479-482.
  16. Witte, K., Clark, A., Cleland, J. (2001). Chronic heart failure and micronutrients. Journal of the American College of Cardiology. 37 (7): 1765-1774.
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