
 Aldosterone receptor antagonists – how cardiovascular actions may explain their        
  beneficial effects in heart failure
  Ovaert, P., Elliott, J., Bernay, F., Guillot, E., Bardon, T.
  Journal of Veterinary Pharmacology and Therapeutics, 2010, 33:109-117
Les  antagonistes  de  l’aldostérone  ont  été  considérés  longtemps  comme  diurétiques  épargnant  du  potassium. 
Toutefois, vu que l’aldostérone joue un rôle important dans des processus impliqués dans la progression de l’insuf-
fisance cardiaque chez l’homme et l’animal, on a fait récemment beaucoup de progrès en recherches sur d’autres 
applications de ces molécules. Cet article résume la littérature disponible concernant l’influence de l’aldostérone sur 
le myocarde, les vaisseaux sanguins et le système nerveux autonome en cas d’insuffisance cardiaque.
Il  existe  de  nombreuses  études  démontrant  le  rôle 
que joue l’aldostérone dans l’apparition de la fibrose 
myocardique  et  la  prévention  de  celle-ci  par  des  an-
tagonistes  de  l’aldostérone.  Il  a  été  démontré  que  le 
développement  de  la  fibrose  du  myocarde  entraîne 
une rigidité anormale du myocarde, conduisant à une 
dysfonction ventriculaire diastolique et systolique, abou-
tissant à la progression de l’insuffisance cardiaque 
chez l’homme.
Les antagonistes de l’aldostérone, comme la spiro-
nolactone, aident à prévenir la fibrose myocardique. 
Ceci permet d’expliquer leur effet bénéfique clair sur la réduction du risque de mortalité chez le chien et l’homme 
souffrant d’insuffisance cardiaque. La fibrose myocardique a été démontrée chez les animaux de laboratoire, les 
chiens et l’homme souffrant d’insuffisance cardiaque. Dans une publication récente de Falk et al. (2006, 2007) 
les chiens souffrant d’insuffisance cardiaque avaient significativement plus de fibrose myocardique que les chiens 
sains et plus le degré de fibrose était élevé, plus la durée de survie était courte. Yang et al. (2008) ont conclu que 
la spironolactone aidait à prévenir la fibrillation atriale chez le chien souffrant d’insuffisance cardiaque induite grâce 
à une réduction de la fibrose dans l’atrium.
L’aldostérone induit une élasticité réduite des vaisseaux sanguins, conduisant à une augmentation de la résistance 
périphérique. On a observé une amélioration de la fonction endothéliale après l’utilisation de la spironolactone chez 
l’homme. L’aldostérone a également un effet délétère sur l’activité du système parasympathique. Grâce au traite-
ment aux antagonistes de l’aldostérone, on a réussi à ralentir le rythme cardiaque et à en améliorer la variabilité. 
Chez le chien, un réflexe barorécepteur altéré et une réaction réduite du rythme cardiaque aux changements dans 
la pression sanguine ont également été constatés.
Les  antagonistes  de  l’aldostérone,  comme  la  spironolactone,  aident  à  prévenir  la  fibrose  du   
myocarde et ils ont un effet bénéfique sur la mortalité chez l’homme et l’animal souffrant d’insuffi-
sance cardiaque.
Falk, T.,  Jönsson,  L.,  Olsen, L.H.,  Pedersen,  H.D. (2006)  Arteriosclerotic  changes in  myocardium,  lung  and  kidney  in  dogs  with chronic 
congestive heart failure and myxomatous valve disease. Cardiovascular Pathology, 15, 185-193.
Falk, T., Jönsson, L., Olsen, L.H., Tarnow, I., Pedersen, H.D. (2007) Correlation of cardiac pathology and clinical findings in dogs with naturally 
occurring congestive heart failure. Abstract. Proceedings of the 17th annual ECVIM congress. Budapest Hungary, Sept. 13th-15th. 
Yang, S., Han., W., Zhou, H., Dong, G., Wang, B., Huo, H., Wei, N., Cao, Y., Zhou, G., Xiu, C. & Li, W. (2008) Effects of spironolactone on 
electrical and structural remodelling of atrium in congestive heart failure dogs.Chinese Medical Journal, 121, 38-42.
ACTION 
ANTIFIBROTIQUE…
ADVERTORIAL
Two New Publications Discuss the Use and Benefi ts 
of Spironolactone in Dogs
Fraser Broadfoot BVetMed GPCert(SAP) MRCVS
This article summarises two new publications that discuss the clinical benefi ts of giving spironolactone 
(Prilactone®, CEVA Animal Health) as part of fi rst-line therapy to dogs with congestive heart failure caused 
by mitral valve disease.
The aim of this study was to determine the clinical effi cacy of spironolactone 
for dogs with mitral valve disease when added as part of fi rst-line congestive 
heart  failure  therapy.  212  dogs  were  enrolled  onto  the  study  and  were 
randomised, under double blind conditions, to receive either spironolactone 
or  placebo.  All  dogs  also  received  an  ACE  inhibitor  and  other  authorised 
treatments  included  furosemide,  digoxin  and  L-carnitine.    The  study  was 
continued for 15 months and the following end-points were recorded:
•  death or euthanasia due to heart failure (mortality) 
•  severe  worsening  of  heart  failure  (morbidity),  defi ned  as  the  need  to 
introduce  an  unauthorised  cardiac  therapy  or  to  increase  the  dose  of 
furosemide over 10mg/kg/day to prevent life-threatening oedema
By the end of this period, 10.8% of dogs in the spironolactone group reached 
the end-point  (death, euthanasia  and  severe worsening) versus 25.5%  of 
dogs in the placebo group. This represents a 55% reduction in the risk of 
cardiac morbidity-mortality (p = 0.017), see fi gure 1, and an even greater 
69% reduction in the risk of mortality (p = 0.0071).
These results were highly statistically signifi cant and support the use of 
Prilactone® as part of fi rst-line therapy for the treatment of dogs with 
congestive heart failure caused by mitral valve disease.
This paper summarises the mode of action of spironolactone which, as an 
aldosterone antagonist, has traditionally been classifi ed only as a potassium-
sparing diuretic.  However it has now been discovered that aldosterone plays 
a pivotal role in many other pathogenic processes involved in the progression 
of heart failure, including myocardial fi brosis, see fi gure 2.
In human patients, the development of myocardial fi brosis has been shown 
to cause abnormal myocardial stiffness, leading to ventricular diastolic and 
systolic dysfunction and ultimately to progression of heart failure. In recent 
studies, Falk 
et al
. (2006/2007)  showed that  dogs  with  congestive heart 
failure had signifi cantly more myocardial fi brosis than control dogs and the 
higher the degree of fi brosis then the shorter the survival time.
Aldosterone  antagonists,  such  as  spironolactone,  help  to  prevent 
myocardial  fi brosis  and  this  helps  to  explain their  marked  benefi cial 
effects on reducing the risk of mortality in dogs and people with heart 
failure.
Effi cacy of Spironolactone on Survival in Dogs with Naturally-occurring 
Mitral Regurgitation Caused by Myxomatous Mitral Valve Disease.
Bernay, F., Bland, J.M., Häggström, J., Baduel, L., Combes, B., Lopez, A., Kaltsatos, 
V. (2010),  
Journal of Veterinary Internal Medicine
. In Press.
Aldosterone receptor antagonists – how cardiovascular actions may 
explain their benefi cial effects in heart failure.
Ovaert P., Elliott J., Bernay F., Guillot E., Bardon T. (2010), 
Journal of Veterinary 
Pharmacology and Therapeutic.
 In Press. 
Figure 1: Survival curve for dogs receiving spironolactone (Prilactone®) versus those receiving 
placebo (end point = death/euthanasia and severe worsening due to cardiac disease)
Figure 2: Myocardial subendocardial and interstitial fi brosis; areas of fi brosis (collagen) are coloured 
in blue. Photo. I. Raymond-Letron National Veterinary School of Toulouse, France.
For further information about how Prilactone® can be incorporated into your 
heart failure treatment regimes, please contact Fraser Broadfoot MRCVS by 
telephone on 01494 781510 or by email at fraser.broadfoot@ceva.com.
Other references
Falk, T., Jönsson, L., Olsen, L.H., Pedersen, H.D. (2006), Arteriosclerotic changes in myocardium, lung and kidney in dogs with chronic congestive heart failure and myxomatous valve disease, Cardiovascular Pathology, 15, p185-
193. Falk, T., Jönsson, L., Olsen, L.H., Tarnow, I., Pedersen, H.D. (2007), Correlation of cardiac pathology and clinical fi ndings in dogs with naturally occurring congestive heart failure. Abstract. Proceedings of the 17th annual ECVIM 
congress. Budapest Hungary, September 13th -15th. Abstract 23.
Prilactone® contains spironolactone  POM-V   Further information is available from CEVA Animal Health Ltd, 90 The Broadway, Chesham, Bucks HP5 1EG
UK Vet A4 Prilactone Advertorial Feb 10.indd   1 11/02/2010   09:54
Fibrose myocardique et interstitielle; les zones de fibrose
(collagène) sont colorées en bleu.