Treatment

Chronic kidney disease (CKD) can lead to a variety of different clinical signs and complications. The majority of patients have azotaemia (increased waste products in the blood), but other complications vary from patient to patient. Each patient should be assessed to identify which problems need to be addressed, and treatment should be tailored accordingly. Some treatments will address more than one problem.

• Treatment aims
• Main classes of therapy
• Which treatment for which complication?

Treatment aims

Treatment aims of CKD are to improve quality of life by reducing the clinical signs, to increase life expectancy and to prevent further damage in order to delay disease progression.

This is achieved by:

• Managing dehydration (fluid support)
• Reducing proteinuria (ACE inhibitor – Fortekor® (benazepril hydrochloride))
• Reducing systemic and glomerular hypertension (Fortekor +/- other antihypertensive therapies)
• Controlling phosphate levels (diet, phosphate binders, calcitriol)
• Reducing uraemia (diet, fluid support)
• Correcting electrolyte abnormalities (fluid support, oral supplements)
• Treatment of underlying infections (antibiotics)
• Management of anaemia (erythropoietin)
• Symptomatic therapy (e.g. antie-metics, antacids/gastric protectants)

Main classes of therapy

• ACE inhibitor (Fortekor)
• Diet
• Calcium channel blockers
• Phosphate binders
• Potassium supplementation
• Antibiotics
• Erythropoetin
• Others
• 

Ace inhibitor

Benazepril hydrochloride (Fortekor) is the only ACE inhibitor licensed for the treatment of CKD in cats. Fortekor has several benefits:

• It normalises glomerular pressure – this protects the kidneys and slows down disease progression, helping prolong survival – while preserving glomerular filtration rate (GFR)
• It reduces proteinuria – the reduction in glomerular hypertension reduces protein loss into the urine
• It increases appetite
• It reduces systemic blood pressure by around 10-20 mmHg (additional therapy may be needed in severely hypertensive patients)

Due to its effect in reducing glomerular pressure, Fortekor should theoretically cause a fall in GFR. However studies have shown that GFR is maintained, probably through beneficial effects on the basement membrane leading to improved filtration efficiency.¹ Read more about the benefits of Fortekor.

Reference 1. S. Brown et al. (2001) Am J Vet Res, 62, 375-383.

Diet

Specific ‘renal’ diets are available. These have restricted levels of good-quality protein in order to minimise the amount of waste products the body has to deal with. This helps to reduce the development of azotaemia. They are also restricted in phosphate, which helps to reduce the effects of renal secondary hyperparathyroidism. Feeding a low protein/low phosphate diet makes a significant difference to life expectancy and should always be part of the management protocol. However, these diets may be less palatable than normal cat food and compliance can be difficult.

Calcium channel blockers (for example, amlodipine) 

Some calcium channel blockers are potent antihypertensive agents and are used if severe systemic hypertension is present. Although they reduce systemic pressure, they have no specific effect on glomerular pressure; therefore, an ACE inhibitor such as Fortekor should still be considered in hypertensive CKD patients. If used together, blood pressure should be closely monitored as there could be an additive effect, potentially leading to hypotension.

Phosphate binders

If the low phosphate diet is not successful in keeping blood phosphate levels at a normal level (consider: rate), a phosphate binder can be added to the food to prevent phosphate from being absorbed from the gastrointestinal tract.

Potassium supplementation

Oral potassium supplements can be added to the food if necessary.

Antibiotics

Bacterial urinary tract infections are commonly seen and will require treatment with the appropriate antibiotics. The antibiotic should be selected with care, as some are toxic to kidneys, or may require dose adjustment if they are excreted through the kidneys. If pyelonephritis is suspected, longer courses of treatment (4-6 weeks) may be necessary.

Erythropoietin

Anaemia may develop due to the kidneys being unable to produce adequate levels of erythropoietin, which stimulates red blood cell production. Human erythropoietin can be injected; however, it is very expensive and can only be used for a limited period of time, so is not part of routine management of CKD cases.

Others

• Traditionally anabolic steroids were administered to stimulate the appetite and help maintain muscle mass, but there is no evidence that they are beneficial
• Fluid therapy (intravenous or subcutaneous) is used in dehydrated patients
• Symptomatic therapy is given when required, for example, to treat vomiting or ulcers

Which treatment for which complication?

Below is an overview of the major complications of CKD and the treatments used for each one: