2019

All treatments for chronic kidney disease (CKD) need to be tailored to theindividual patient. The following recommendations are useful starting
points for the majority of cats at each stage. Serial monitoring of thesepatients is ideal and treatment should be adapted according to the
response to treatment. Note that staging of disease is undertaken
following diagnosis of CKD – an increased blood creatinine o r
S D M A concentration alone is not diagnostic of CKD.
Treatment recommendations fall into two broad categories, namely:
1. Those that slow progression of CKD and so preserve remaining kidney
function for longer
2. Those that address the quality of life of the cat, addressing the clinicalsigns of CKD
In general, at the early stages of CKD (stages 1 and 2), there are few clinicalextra-renal signs of the disease and the therapeutic emphasis is on slowing
progression. From stage 3 onwards, extra-renal signs become morecommon and more severe. The importance of administering treatments
which address the clinical signs of CKD and improve the cat’s quality of life
assume greater importance and exceeds the importance of treatments
designed to slow progression by stage 4.
Some of the treatment recommendations are not authorized for use in all
geographical regions and some may not be authorized for use in cats. Such
recommended dose rates are therefore empirical. It is the treating
veterinarian’s duty to make a risk:benefit assessment for each patient priorto administering any treatment.

1© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)
1

Treatment recommendations for Cats with Chronic Kidney Disease

Stage 1 Feline patients:
1. Discontinue all potentially nephrotoxic drugs if possible.
2. Identify and treat any pre-renal or post-renal abnormalities.
3. Rule out any treatable conditions like pyelonephritis and renal urolithiasis withradiographs and/or ultrasonography.
4. Measure blood pressure and urine protein to creatinine ratio (UP/C).
Management of dehydration:
In these patients urine concentrating ability may be somewhat impaired and therefore ensure:

They have fresh water available at all times for drinking

If become ill for any reason that leads to fluid losses, correct clinical dehydration withisotonic polyioinic replacement fluid solutions (e.g. lactated Ringer’s) IV or SQ, promptly
as needed

Systemic hypertension:
The blood pressure above which progressive renal injury may be induced is unknown.
Our goal is to reduce systolic blood pressure to <160 mm Hg and to minimize the riskof extra-renal target organ damage (CNS, retinal, cardiac problems/damage). If there
is no evidence of such damage but systolic blood pressure persistently exceeds 160
mm Hg, increasing the risk of this occurring, treatment should be instituted.
‘Persistence’ of increased systolic blood pressure should be judged on multiple
measurements made over the following time-scales in these blood pressure
substages:• Hypertensive (moderate risk of future target organ damage) – systolic bloodpressure 160 to 179 mm Hg measured over 1 to 2 weeks• Severely hypertensive (high risk of future target organ damage) – systolic bloodpressure 180 mm Hg measured over 1 to 2 weeks.
If evidence of target organ damage exists, cats should be treated without the needto demonstrate persistently increased systolic blood pressure. Reducing bloodpressure is a long term aim in managing the patient with CKD and a gradual andsustained reduction should be the goal, avoiding any sudden or severe decreases
leading to hypotension.
A logical stepwise approach to managing hypertension is as follows:
1. Dietary sodium (Na) reduction - there is no evidence that lowering dietary Na
will reduce blood pressure. If dietary Na reduction is attempted, it should beaccomplished gradually and in combination with pharmacological therapy.
2. Calcium channel blocker (CCB), such as amlodipine (0.125 to 0.25 mg/kg once
daily) or angiotensin receptor blocker (ARB), telmisartan (2 mg/kg once daily).

2© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)1
3. Double the dose of amlodipine (0.25 to 0.5 mg/kg once daily) if this is treatment selected.
Note telmisartan label does not advise a dose increase from 2 mg/kg once daily.
4. Combine amlodipine and telmisartan if either drug alone does not lead toadequate control of blood pressure.
Note: Take care not to introduce CCB/RAAS inhibitor treatment to unstable
dehydrated cats as glomerular filtration rate may drop precipitously if these drugs
are introduced before the patient is adequately hydrated.
Monitoring response to antihypertensive treatment:
Hypertensive cats normally require lifelong therapy and may require treatment
adjustments. Serial monitoring is essential. After stabilization, monitoring should
occur at least every 3 months.
Systolic blood pressure <120 mm Hg and/or clinical signs such as weakness or
tachycardia indicate hypotension, which is to be avoided.
Blood creatinine concentration – reducing blood pressure may lead to small andpersistent increases in creatinine concentration (<45 µmol/l or 0.5 mg/dl increase)or SDMA concentration (<2.0 µg/dl), but a marked increase suggests an adverse
drug effect. Progressively increasing concentrations indicate progressive kidneydamage/disease.
Proteinuria:
Cats in Stage 1 with UP/C >0.4 should be investigated for disease processes leading
to proteinuria (see 1 and 2 below) and treated with anti-proteinuric measures (see 3
and 4 below).
Those with borderline proteinuria (UP/C 0.2 to 0.4) require close monitoring (see 1
and 4 below).
1. Look for any concurrent associated disease process that may be treated/corrected.
2. Consider kidney biopsy as a means of identifying underlying disease (seeAppendix and consult experts if unsure of indications for kidney biopsy).
3. Administer an RAAS inhibitor (ACEI or ARB) and feed a clinical renal diet.
4. Monitor response to treatment / progression of disease:– stable blood creatinine concentration and decreasing UP/C = good response.
– serially increasing blood creatinine concentrations and/or increasing UP/C =disease is progressing.
Ordinarily therapy will be maintained lifelong unless the underlying disease has been
resolved in which case dose reduction whilst monitoring UP/C might be considered.
Note:a. The use of an RAAS inhibitor is contraindicated in any cat that is clinicallydehydrated or is showing signs of hypovolemia. Correct dehydration before
using these drugs otherwise glomerular filtration rate may drop precipitously.
b. Cats with proteinuria and hypoalbuminemia likely share the same thromboembolic3© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)1
risk as dogs (although evidence is lacking in the published literature), but aspirin isdifficult to use in cats to achieve a selective antiplatelet effect. A suggested dose
rate if plasma albumin is below 20 g/l (2 g/dl) is 1 mg/kg every 72 hours and analternative to aspirin is clopidogrel (10 to 18.75 mg/day).
c. Cats with serum phosphate within the IRIS target (4.5 mg/dl or 1.5 mmol/l) may beat increased risk of developing hypercalcemia when renal diets are introduced.
Monitor serum calcium and if total calcium exceeds 12 mg/dl (3 mmol/l) switch thecat to a senior diet or mix renal diet (50:50 by volume) with standard grocery food.
d. If borderline proteinuria persists, antiproteinuric treatment could be offered,because the association between progression of CKD and proteinuria includes
the borderline category. However, there is at present no evidence thatintervention with anti-proteinuric drugs slows progression.

4© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)

Stage 2 Feline patients:
2

All of the above listed for Stage 1 (listed here again for convenience) plus any additional
steps indicated.
1. Discontinue all potentially nephrotoxic drugs if possible.
2. Identify and treat any pre-renal or post-renal abnormalities.
3. Rule out any treatable conditions like pyelonephritis and renal urolithiasis withradiographs and/or ultrasonography.
4. Measure blood pressure and urine protein to creatinine ratio (UP/C).
5. Consider feeding a clinical renal diet: this may be accomplished more easily
early in the course of CKD, before inappetence develops.
Management of dehydration:
These patients often have decreased urine concentrating ability and therefore ensure:•

They have fresh water available at all times for drinking•

If become ill for any reason that leads to fluid losses, correct clinical dehydration withisotonic polyioinic replacement fluid solutions (e.g. lactated Ringer’s) IV or SQ, promptly
as needed

Systemic hypertension:
The blood pressure above which progressive renal injury may be induced is unknown.
Our goal is to reduce systolic blood pressure to <160 mm Hg and to minimize the riskof extra-renal target organ damage (CNS, retinal, cardiac problems/damage). If there
is no evidence of this but systolic blood pressure persistently exceeds 160 mm Hg,
increasing the risk of such damage, treatment should be instituted.
‘Persistence’ of increased systolic blood pressure should be judged on multiple
measurements made over the following time-scales in these blood pressure
substages:• Hypertensive (moderate risk of future target organ damage) – systolic bloodpressure 160 to 179 mm Hg measured over 1 to 2 weeks.
• Severely hypertensive (high risk of future target organ damage) – systolic bloodpressure 180 mm Hg over 1 to 2 weeks.
If evidence of target organ damage exists, cats should be treated without the need todemonstrate persistently4increased systolic blood pressure. Reducing blood pressure
is a long term aim in managing the patient with CKD and a gradual and sustained
reduction should be the goal, avoiding any sudden or severe decreases leading tohypotension.
A logical stepwise approach to managing hypertension is as follows:
1. Dietary sodium (Na) reduction - there is no evidence that lowering dietary Na
will reduce blood pressure. If dietary Na reduction is attempted, it should beaccomplished gradually and in combination with pharmacological therapy.
2. Calcium channel blocker (CCB) such as amlodipine (0.125 to 0.25 mg/kg once daily) or
angiotensin receptor blocker (ARB), telmisartan (2 mg/kg once daily).
5© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)2

3. Double the dose of amlodipine (0.25 to 0.5 mg/kg once daily). if this is treatment selected.
Note telmisartan label does not advise a dose increase from 2 mg/kg once daily.
4. Combine amlodipine and telmisartan if either drug on its own does not lead toadequate control of blood pressure
Take care not to introduce CCB/RAAS inhibitor treatment to unstable dehydrated
cats as glomerular filtration rate may drop precipitously if these drugs are introduced
before the patient is adequately hydrated.
Monitoring response to antihypertensive treatment:
Hypertensive cats normally require lifelong therapy and may require treatment
adjustments. Serial monitoring is essential. After stabilization, monitoring should
occur at least every 3 months.
Systolic blood pressure <120 mm Hg and/or clinical signs such as weakness or
tachycardia indicate hypotension, which is to be avoided.
Blood creatinine concentration – reducing blood pressure may lead to small andpersistent increases in creatinine (<45 µmol/l or 0.5 mg/dl increase) or SDMA
concentration (<2.0 µg/dl), but a marked increase suggests an adverse drug
effect. Progressively increasing creatinine concentrations indicate progressive
kidney damage/disease.
Proteinuria:
Cats in Stage 2 with UP/C >0.4 should be investigated for disease processes
leading to proteinuria (see 1 and 2 below) and treated with anti-proteinuric
measures (see 3 and 4 below).
Those with borderline proteinuria (0.2 to 0.4) require close monitoring (see 1
and 4 below).
1. Look for any concurrent associated disease process that may be treated/corrected.
2. Consider kidney biopsy as a means of identifying underlying disease (seeAppendix and/or consult experts if unsure of indications for kidney biopsy).
3. Administer an RAAS inhibitor (ACEI or ARB) and feed a clinical renal diet.
4. Monitor response to treatment/progression of disease:– stable blood creatinine concentration and decreasing UP/C = good response.
– serially increasing creatinine concentrations and/or increasing UP/C =disease is progressing.
– Ordinarily therapy will be maintained lifelong unless the underlying
disease has been resolved in which case dose reduction while
monitoring UP/C might be considered.
Note:a. Use of an RAAS inhibitor is contraindicated in any animal that is clinicallydehydrated and/or showing signs of hypovolemia. Correct dehydration before
using these drugs otherwise glomerular filtration rate may drop precipitously.
b. Cats with proteinuria and hypoalbuminemia likely share the same thromboembolicrisk as dogs, (although evidence is lacking in the published literature), but aspirin isdifficult to use in cats to achieve a selective antiplatelet effect. A suggested dose rate
if plasma albumin is below 20 g/l (2 g/dl) is 1 mg/kg every 72 hours and an alternative
to aspirin is clopidogrel (10 to 18.75 mg/day).
6© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)2

c. Cats with serum phosphate within the IRIS target may be at increased risk ofdeveloping hypercalcemia when renal diets are introduced. Monitor serum calcium
and if total calcium exceeds 12 mg/dl (3 mmol/l) switch the cat to a senior diet or mix
renal diet (50:50 by volume) with standard grocery food.
d. If borderline proteinuria is persistent, antiproteinuric treatment could be offered. The
rationale for doing so is that there is an association between progression of CKD andproteinuria which extends into the borderline category. There is no evidence
that intervention with anti-proteinuric drugs slows progression, however.
Reduction of phosphate intake:
Many cats in Stage 2 will have normal plasma phosphate concentrations but will haveincreased plasma PTH concentration. Evidence suggests that chronic reduction ofphosphate intake to maintain a plasma phosphate concentration below 1.5 mmol/l(but not less than 0.9 mmol/l; <4.6 mg/dl but >2.7 mg/dl) is beneficial to patients with
CKD.
The following measures can be introduced sequentially in an attempt to achieve this:
1. Dietary phosphate restriction (i.e., clinical renal diet therapy).
2. If plasma phosphate concentration remains above 1.5 mmol/l (4.6 mg/dl) after
dietary restriction, give enteric phosphate binders (such as aluminum hydroxide,
aluminum carbonate, calcium carbonate, calcium acetate, lanthanum carbonate)
to effect, starting at 30-60 mg/kg/day in divided doses to be mixed with eachmeal (mixed with the food). The dose required will vary according to the amountof phosphate being fed and the stage of kidney disease. Treatment withphosphate binders should be to effect (as outlined above), with signs of toxicity
limiting the upper dose rate possible in a given patient. Monitor serum calcium
and phosphate concentrations every 4-6 weeks until stable and then every 12
weeks. Microcytosis and/or generalized muscle weakness and neurologicalsigns suggest aluminum toxicity if using an aluminum containing binder – switch
to another form of phosphate binder should this occur. It should be noted,
however, unlike the dog, aluminum toxicity has not been reported in the cat and it
is possible to measure blood aluminum levels to confirm suspected cases.
Hypercalcemia should be avoided – combinations of aluminum and calcium
containing phosphate binders may
be necessary in some cases.
Additional recommendations for Stage 2 patients:
If the patient is hypokalemic, then potassium gluconate or potassium citrate should
be supplemented to effect (typically 1-2 mmol/kg/day).
Where there is a discrepancy between creatinine and SDMA:
If serum or plasma SDMA is persistently >25 µg/dl in a cat with serum creatinine
between 1.6 and 2.8 mg/dl (IRIS CKD Stage 2 based on creatinine), stage and treat
this cat as and IRIS CKD Stage 3 patient.

7© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)3

Stage 3 Feline patients:
The range of presentations for cats in Stage 3 is likely to be wide, from no clinicalsigns to quite marked extra-renal clinical signs. The main treatments mentioned
so far for stages 1 and 2 are aimed at slowing progression of CKD also apply instage 3 and may be the only therapies needed for cats with no or mild extra-renal
signs. However, treatments designed to improve the quality of life of the cat
become more important, the more extra-renal signs are present. These include
treatments to address dehydration, nausea and vomiting, anemia and acidosis.
Treatments include all of the steps listed for Stage 1 and 2 (listed here again forconvenience) plus any additional steps indicated.
1. Discontinue all potentially nephrotoxic drugs if possible.
2. Identify and treat any pre-renal or post-renal abnormalities.
3. Rule out any treatable conditions like pyelonephritis (any urinary tract infection
should be regarded as a potential pyelonephritis and treated appropriately) andrenal urolithiasis with radiographs and/or ultrasonography.
4. Measure blood pressure and urine protein to creatinine ratio (UP/C).
5. Feed a clinical renal diet.
Management of dehydration:
These patients have decreased urine concentrating ability and therefore• correct clinical dehydration/hypovolemia with isotonic, polyionic replacement fluid
solutions (e.g., lactated Ringer’s) IV or SQ as needed.
• have fresh water available at all times for drinking.
• In addition, some of these cats may require maintenance fluids administered routinely tomaintain hydration (see below)
Systemic hypertension:
The blood pressure above which progressive renal injury may be induced is unknown.
Our goal is to reduce systolic blood pressure to <160 mm Hg and to minimize the riskof extra-renal target organ damage (CNS, retinal, cardiac problems/damage). If there
is no evidence of this but systolic blood pressure persistently exceeds 160 mm Hg
increasing the risk of extra-renal target organ damage, treatment should be instituted.
‘Persistence’ of increase in systolic blood pressure should be judged on multiple
measurements made over the following time-scales in these blood pressure
substages:
Hypertensive (moderate risk of future target organ damage) – systolic bloodpressure 160 to 179 mm Hg measured over 1 to 2 weeks.
• Severely hypertensive (high risk of future target organ damage) – systolic bloodpressure 180 mm Hg measured over 1 to 2 weeks.
If evidence of target organ damage exists, cats should be treated without the need todemonstrate persistently increased systolic blood pressure. Reducing blood pressure
is a long term aim in managing the patient with CKD and a gradual and sustained
reduction should be the goal, avoiding any sudden or severe decreases leading tohypotension.
8© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)
A logical stepwise approach to managing hypertension is as follows:3

1. Dietary sodium (Na) reduction – there is no evidence that lowering dietary Na
will reduce blood pressure. If dietary Na reduction is attempted, it should beaccomplished gradually and in combination with pharmacological therapy.
2. Calcium channel blocker (CCB) such as amlodipine (0.125 to 0.25 mg/kg
once daily) or angiotensin receptor blocker (ARB), telmisartan (2 mg/kg
once daily)
3. Double the dose of amlodipine (0.25 to 0.5 mg/kg once daily) if this is treatment selected.
Note telemisartan label does not advise a dose increase from 2 mg/kg once daily.
4. Combine amlodipine and telmisartan if either drug on its own does not lead toadequate control of blood pressure.
Note: Take care not to introduce CCB/RAAS inhibitor treatment to unstable
dehydrated cats as glomerular filtration rate may drop precipitously if these drugs
are introduced before the patient is adequately hydrated
Monitoring response to antihypertensive treatment:
Hypertensive cats normally require lifelong therapy and may require treatment
adjustments. Serial monitoring is essential. After stabilization, monitoring should
occur at least every 3 months.
Systolic blood pressure <120 mm Hg and/or clinical signs such as weakness or
tachycardia indicate hypotension, which is to be avoided.
Blood creatinine concentration – reducing blood pressure may lead to small andpersistent increases in creatinine concentration (<45 µmol/l or 0.5 mg/dl increase)or SDMA concentration (<2.0 µg/dl), but a marked increase suggests an adverse
drug effect. Progressively increasing concentrations indicate progressive kidneydamage/disease.
Proteinuria:
Cats in Stage 3 with urine protein to creatinine ratio (UP/C) >0.4 should be
investigated for disease processes leading to proteinuria (see 1 and 2 below) andtreated with anti-proteinuric measures (see 3 and 4 below).
Those with borderline proteinuria (0.2 to 0.4) require close monitoring (see 1
and 4 below).
1. Look for any concurrent associated disease process that may be treated/corrected.
2. Consider kidney biopsy as a means of identifying underlying disease (seeAppendix and/or consult experts if unsure of indications for kidney biopsy).
3. Administer an RAAS inhibitor (ACEI or ARB) and feed a clinical renal diet.
4. Monitor response to treatment / progression of disease:– stable blood creatinine concentration and decreasing UP/C = good response.
– serially increasing creatinine concentrations and/or increasing UP/C =disease is progressing.
Ordinarily therapy will be maintained lifelong unless the underlying disease has been
resolved in which case dose reduction whilst monitoring UP/C might be considered.
9© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)
Note:

3

a. Use of an RAAS inhibitor is contraindicated in any animal that is clinicallydehydrated and/or is showing signs of hypovolemia. Correct dehydration
before using these drugs otherwise glomerular filtration rate may drop
precipitously.
b. Cats with proteinuria and hypoalbuminemia likely share the same
thromboembolic risk as dogs, (although evidence is lacking in the publishedliterature), but aspirin is difficult to use in cats to achieve a selective antiplatelet
effect. A suggested dose rate if plasma albumin is below 20 g/l (2 g/dl) is 1
mg/kg every 72 hours and an alternative to aspirin is clopidogrel (10 to 18.75
mg/day).
c. Cats with serum phosphate within the IRIS target may be at increased risk ofdeveloping hypercalcemia when renal diets are introduced. Monitor serum
calcium and if total calcium exceeds 12 mg/dl (3 mmol/l) switch to a senior dietor mix renal diet (50:50 by volume) with standard grocery food.
d. If borderline proteinuria is persistent, antiproteinuric treatment could beoffered. The rationale for doing so is that there is an association between
progression of CKD and proteinuria which extends into the borderline
category. However, there is at present no evidence that intervention with antiproteinuric drugs slows progression.
Reduction of phosphate intake:Evidence suggests that chronic reduction of phosphate intake to maintain a plasma
phosphate concentration below 1.5 mmol/l (but not less than 0.9 mmol/l; <4.6 mg/dl
but >2.7 mg/dl) is beneficial to patients with CKD.
A more realistic post-treatment target plasma phosphate concentration for cats at
Stage 3 is <1.6 mmol/l (5.0 mg/dl).
The following measures can be introduced sequentially in an attempt to achieve this:
1. Dietary phosphate restriction (i.e., clinical renal diet therapy).
2. If plasma phosphate concentration remains above 1.6 mmol/l (4.6 mg/dl) after
dietary restriction, give enteric phosphate binders (such as aluminum hydroxide,
aluminum carbonate, calcium carbonate, calcium acetate, lanthanum carbonate)
to effect, starting at 30-60 mg/kg/day in divided doses to be mixed with each meal(mixed with the food). The dose required will vary according to the amount ofphosphate being fed and the IRIS stage. Treatment with phosphate binders should
be to effect (as outlined above), with signs of toxicity limiting the upper dose ratepossible in a given patient. Monitor serum calcium and phosphate concentrations
3. every 4-6 weeks until stable and then every 12 weeks. Microcytosis and/or
generalized muscle weakness and neurological signs suggest aluminum toxicity ifusing an aluminum containing binder – switch to another form of phosphate binder
should this occur. It should be noted, however, unlike the dog, aluminum toxicity has
not been reported in the cat and it is possible to measure blood aluminum levels to
confirm suspected cases. Hypercalcemia should be avoided – combinations ofaluminum and calcium containing phosphate binders may be necessary in somecases.
10© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)3

4. Although there is evidence that judicious use of calcitriol prolongs survival in dogs
at IRIS Stage 3, beneficial effects of ultra-low dose calcitriol have not yet been
established in cats.

Additional recommendations for Stage 2 and 3 patients:
1. If the patient is hypokalemic, then potassium gluconate or potassium citrateshould be supplemented to effect (typically 1-2 mmol/kg/day).
Additional recommendations for stage 3 patients
2. If metabolic acidosis exists (blood bicarbonate or total CO<16 mmol/l) once the2patient is stabilized on the diet of choice, supplement with oral sodium
bicarbonate, (or potassium citrate if hypokalemic) to effect to maintain bloodbicarbonate/ total CO in the range of 16-24 mmol/l.
2
3. Treat vomiting / decreased appetite / nausea / weight loss with anantiemetic /appetite stimulant / antinausea agent (such as maropitant,
ondansetron or mirtazapine). Evidence suggests mirtazapine (1.88 mg/cat
every 48 h for 3 weeks) reduces vomiting, improves appetite and leads toweight gain in cats showing signs of inappetence and vomiting in this stage.
Maropitant (1 mg/kg daily for 2 weeks) reduced vomiting but did not lead toweight gain/ improved appetite. Further investigations are needed on theuse of these and other drugs to determine whether they are useful for
managing gastrointestinal disturbances in cats with CKD and uremia whenadministered longer term.
4. Give appropriate maintenance fluids parenterally as necessary to maintainhydration (see Footnote).
5. Drugs that rely predominantly on renal function for their clearance fromthe body should be used with caution in patients in Stage 3 CKD. It may
be necessary to adjust the dose of these drugs (depending on their
therapeutic indices) to avoid accumulation.

Where there is a discrepancy between creatinine and SDMA:
If serum or plasma SDMA is persistently >35 µg/dl in a cat with serum
creatinine between 2.8 and 5 mg/dl (IRIS CKD stage 3 based on
creatinine) stage and treat the cat as an IRIS CKD Stage 4 patient.

11© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)

Stage 4 Feline patients:
4

Most cats with stage 4 CKD have many extra-renal signs present. Although it isstill important to administer treatments which slow progression of CKD, theimportance of improving quality of life for these cats is greater at this stage.
Therapies directly addressing clinical signs and aimed at improving quality of life
include management of dehydration, acidosis, vomiting and nausea and anemia.
Treatments include all of the steps listed for listed for Stages 1, 2 and 3 (listed
again for convenience) plus any additional steps indicated.
1. Discontinue all potentially nephrotoxic drugs if possible.
2. Identify and treat any pre-renal or post-renal abnormalities.
3. Rule out any treatable conditions like pyelonephritis and renal urolithiasis withradiographs and/or ultrasonography.
4. Measure blood pressure and urine protein to creatinine ratio (UP/C).
5. Feed a clinical renal diet.
Management of dehydration:
These patients have decreased urine concentrating ability and therefore ensure:• correct clinical dehydration/hypovolemia with isotonic, polyionic replacement
fluid solutions (e.g., lactated Ringer’s) IV or SQ, promptly as needed.
• have fresh water available at all times for drinking.
• In addition, these cats may require maintenance fluids administered routinely to maintainhydration (see below)
Systemic hypertension:
The blood pressure above which progressive renal injury may be induced is unknown.
Our goal is to reduce systolic blood pressure to <160 mm Hg and to minimize the riskof extra-renal target organ damage (CNS, retinal, cardiac problems/damage). If there
is no evidence of this but systolic blood pressure persistently exceeds 160 mm Hg,
increasing the risk of such damage, treatment should be instituted.
‘Persistence’ of increase in systolic blood pressure should be judged on multiple
measurements made over the following time-scales in these blood pressure
substages:• Hypertensive (moderate risk of future target organ damage) – systolic bloodpressure 160 to 179 mm Hg measured over 1 to 2 weeks.
• Severely hypertensive (high risk of future target organ damage) – systolic bloodpressure 180 mm Hg measured over 1 to 2 weeks
If evidence of target organ damage exists, cats should be treated without the need todemonstrate persistently increased systolic blood pressure. Reducing blood pressure
is a long term aim in managing the patient with CKD and a gradual and sustained
reduction should be the goal, avoiding any sudden or severe decreases leading tohypotension.
A logical stepwise approach to managing hypertension is as follows:
1. Dietary sodium (Na) reduction - there is no evidence that lowering dietary Na
12© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)4will reduce blood pressure. If dietary Na reduction is attempted, it should beaccomplished gradually and in combination with pharmacological therapy.
2. Calcium channel blocker (CCB) such as amlodipine (0.125 to 0.25 mg/kg once daily) or
angiotensin receptor blocker (ARB), telmisartan (2 mg/kg once daily)..
3. Double the dose of amlodipine (0.25 to 0.5 mg/kg once daily) if this is treatment selected.
Note telemisartan label does not advise a dose increase from 2 mg/kg once daily.
4. Combine amlodipine and telmisartan if either drug on its own does not lead toadequate control of blood pressure.
Note: Take care not to introduce CCB/RAAS inhibitor treatment to unstable
dehydrated cats as glomerular filtration rate may drop precipitously if these drugs
are introduced before the patient is adequately hydrated. The benefit ofcombining drugs to try to reduce blood pressure to below the target should beweighed against the high risk in a stage 4 cat of precipitating an azotemic crisis
should be carefully considered.
Monitoring response to antihypertensive treatment:
Hypertensive cats normally require lifelong therapy and may require treatment
adjustments. Serial monitoring is essential. After stabilization, monitoring should
occur at least every 3 months.
Systolic blood pressure <120 mm Hg and/or clinical signs such as weakness or
tachycardia indicate hypotension, which is to be avoided.
Blood creatinine concentration – reducing blood pressure may lead to small andpersistent increases in creatinine (<45 µmol/l or 0.5 mg/dl increase) or SDMA
concentration (<2.0 µg/dl), but a marked increase suggests an adverse drug effect.
Progressively increasing concentrations indicate progressive kidneydamage/disease.
Proteinuria:
Cats in Stage 4 with urine protein to creatinine ratio (UP/C) >0.4 should be
investigated for disease processes leading to proteinuria (see 1 and 2 below) andtreated with anti-proteinuric measures (see 3 and 4 below).
Those with borderline proteinuria (0.2 to 0.4) require close monitoring (see 1
and 4 below).
1. Look for any concurrent associated disease process that may be treated/corrected.
2. Administer an RAAS inhibitor (ACEI or ARB) and feed a clinical renal diet.
3. Monitor response to treatment / progression of disease:– stable blood creatinine concentration and decreasing UP/C = good response.
– serially increasing creatinine concentrations and/or increasing UP/C =disease is progressing.
Ordinarily therapy will be maintained lifelong unless the underlying disease has been
resolved, in which case dose reduction whilst monitoring UP/C might be considered.

13© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)
Note:

4

a. Use of an RAAS inhibitor is contraindicated in any animal that is clinicallydehydrated and/or is showing signs of hypovolemia. Correct dehydration
before using these drugs otherwise glomerular filtration rate may drop
precipitously.
b. Cats with proteinuria and hypoalbuminemia likely share the same thromboembolicrisk as dogs, (although evidence is lacking in the published literature), but aspirin is difficult
to use in cats to achieve a selective antiplatelet effect. A suggested dose rate if plasma
albumin is below 20 g/l (2 g/dl) is 1 mg/kg every 72 hours and an alternative to aspirin isclopidogrel (10 to 18.75 mg/day).

c. Cats with serum phosphate within the IRIS target may be at increased risk ofdeveloping hypercalcemia when renal diets are introduced. Monitor serum
calcium and if total calcium exceeds 12 mg/dl (3 mmol/l) switch to a senior dietor mix renal diet (50:50 by volume) with standard grocery food.
d. If borderline proteinuria is persistent, antiproteinuric treatment could be offered.
The rationale for doing so is that there is an association between progression of
CKD and proteinuria which extends into the borderline category. However,there is at present no evidence that intervention with anti-proteinuric drugs
slows progression.
Reduction of phosphate intake:Evidence suggests that chronic reduction of phosphate intake to maintain aplasmaphosphate concentration below 1.5 mmol/l (but not less than 0.9 mmol/l;<4.6 mg/dl but >2.7 mg/dl) is beneficial to patients with CKD.
A more realistic post-treatment target plasma phosphate concentration for cats at
Stage 4 is <1.9 mmol/l (6.0 mg/dl).
The following measures can be introduced sequentially in an attempt to achieve this:
1. Dietary phosphate restriction (i.e., clinical renal diet therapy).
2. If plasma phosphate concentration remains above 1.9 mmol/l (6.0 mg/dl) after
dietary restriction, give enteric phosphate binders (such as aluminum hydroxide,
aluminum carbonate, calcium carbonate, calcium acetate, lanthanum carbonate)
to effect, starting at 30-60 mg/kg/day in divided doses to be mixed with eachmeal (mixed with the food). The dose required will vary according to theamount of phosphate being fed and the stage of CKD. Treatment with phosphatebinders should be to effect (as outlined above), with signs of toxicity limiting
the upper dose rate possible in a given patient. Monitor serum calcium andphosphate concentrations every 4-6 weeks until stable and then every 12 weeks.
Microcytosis and/or generalized muscle weakness and neurological signs
suggest aluminum toxicity if using an aluminum containing binder – switch toanother form of phosphate binder should this occur. It should be noted, however,unlike the dog, aluminum toxicity has not been reported in the cat and it ispossible to measure blood aluminum levels to confirm suspected cases.
Hypercalcemia should be avoided – combinationsof aluminum and calcium containing phosphate binders may be necessary insome cases.
3. Although there is evidence that judicious use of calcitriol prolongs survival in dogs
at IRIS Stage 4, beneficial effects of ultra-low dose calcitriol have not yet been
established in cats.
14© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)
Additional recommendations for Stage 2, 3 and 4 patients:

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1. If the patient is hypokalemic, then potassium gluconate or potassium citrateshould be supplemented to effect (typically 1-2 mmol/kg/day).
Additional recommendations for Stage 3 and 4 patients
2. If metabolic acidosis exists (blood bicarbonate or total CO2 <16 mmol/l) once thepatient is stabilized on the diet of choice, supplement with oral sodium bicarbonate
2(orpotassium citrate if hypokalemic) to effect to maintain blood bicarbonate / total
CO in the range of 16-24 mmol/l.
3. Consider treatment for anemia if it is affecting the patient’s quality of life: typicallythis occurs when the PCV is <0.20 l/l (20%). Human recombinant erythropoietin is
the most effective treatment but is not approved for veterinary use: darbepoetin
is preferable as it is less antigenic than epoetin alfa. Anabolic steroids are of no
proven benefit and may be detrimental.
4. Treat vomiting / decreased appetite / nausea / weight loss with an antiemetic/ /appetite
stimulant / antinausea agent (such as maropitant, ondansetron or mirtazapine).
Evidence suggests mirtazapine (1.88 mg/cat every 48 h for 3 weeks) reduces vomiting,
improves appetite and leads to weight gain in cats showing signs of inappetence andvomiting in this stage. Maropitant (1 mg/kg daily for2 weeks) reduced vomiting but did notlead to weight gain/ improved appetite. Further investigations are needed on the use of
these and other drugs to determine whether they are useful for managing gastrointestinal
disturbances in cats with CKD and uremia when administered longer term.
5. Give appropriate maintenance fluids parenterally as necessary tomaintain hydration (see Footnote).
Additional recommendations for Stage 4 patients
6. Intensify efforts to prevent protein / calorie malnutrition. Consider feedingtube intervention (e.g., percutaneous gastrostomy tube).
7. Intensify efforts to prevent dehydration. Feeding tubes can be used toadminister fluids as well as food.
8. Consider dialysis and/or renal transplantation.
Drugs that rely predominantly on renal function for their clearance from thebody should be used with caution in patients in Stage 4 CKD. It may be necessary
to adjust the dose of these drugs (depending on their therapeutic indices) to avoid
accumulation.

15© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).

Treatment Recommendations for CKD in Cats (2019)

Appendix
Reasons for Undertaking Renal Biopsy
1. Renomegaly
2. CKD in a young patient
3. Persistent and severe proteinuria (UP/C>2.0) in a non-azotemic patient
4. Worsening proteinuria in a CKD patient
5. Acute kidney injury, where renal biopsy may provide a prognostic indicator

Footnote
Maintenance fluids to maintain hydration status are low in sodium (30-40 mmol/l) andideally have added potassium (about 13 mmol/l) to ensure daily requirements for
fluid and electrolytes are met (e.g. Normosol-M® or 5% Dextrose plus 0.18% NaClwith added KCl).

Disclaimer
Although every effort has been made to ensure the completeness and accuracy of theinformation provided herein, the IRIS Board assumes no responsibility for thecompleteness or accuracy of the information. All information is provided “as is” without
any warranties, either expressed or implied.

16© 2019 International Renal Interest Society (IRIS) Ltd. IRIS Ltd. is an independent non-profit organization limited by guarantee in the UK (Registered Number 10213173).