ACE inhibitors, or Angiotensin Converting Enzyme inhibitors, to give them their full title, were first developed for use in man after it was found that they reduce excessive amounts of protein in the urine (which is thought to be toxic to the kidneys), reduce blood pressure, and increase lifespan. One ACE inhibitor has now been licensed for use in the management of kidney failure in cats.
Given that kidney failure cannot be cured, one of the most important aspects of treatment is to maintain the best quality of life for the patient.
So perhaps the most important benefit of this treatment was demonstrated in a trial where the owners of CRF cats treated with an ACE inhibitor noted an improvement in their cat's quality of life which was double that when diets alone were used. Furthermore, the survival times for cats suffering from severe kidney disease (cats losing large amounts of protein in their urine) increased by a factor of three after treatment with an ACE inhibitor.
In another study amongst healthy cats, an ACE inhibitor was shown to increase appetite and body weight - which is a potentially useful effect in cats with chronic renal failure (Witte et al. 2003).
An additional benefit of ACE inhibitors is that they lower blood pressure. High blood pressure (hypertension) is found as a consequence of kidney failure in around 20% of CRF cats.
ACE inhibitors are used to treat mild hypertension but additional anti-hypertensive drugs (e.g. amlodipine) may be needed in CRF cats suffering from severe hypertension.