Many CKD cats suffer from constipation, and treating or preventing it can make
a big difference to your cat's quality of life.
It is important to keep a close eye on your cat's litter tray and to deal
promptly with any signs of constipation or straining.
Obviously the ideal is to prevent constipation from ever happening, but that
is not always possible.
Which treatments
to use depends largely upon how severe
your cat's problem is, and whether it is an acute problem or a chronic problem.
What is
Constipation?
Constipation
means the cat has difficulty passing a stool. This can actually take many
forms:
The cat may
not pass stool as frequently as before
The cat
strains in the litter tray
Stools are
hard and dry
In the most
severe cases, the cat does not pass stools at all. Eventually the stool
becomes impacted, which is called obstipation.
Cats with
repeated constipation or obstipation may suffer from reduced motility
related to a distended
colon which can no longer push stool towards the rectum ready to be
passed. This condition is called megacolon.
Constipation is relatively common in CKD cats, but some vets do not seem
to realise this.
Survey of defecation habits in apparently healthy
and chronic kidney disease cats
(2022) Jones SE, Quimby JM, Summers SC, Adams SM, Caney SMA & Rudinsky AJ Journal
of Feline Medicine and Surgery24(2) pp131-141 states
"Constipation can be a significant clinical problem in cats with chronic
kidney disease (CKD)...Under-recognition of subclinical constipation in
CKD cats is likely."
This lack of recognition of the problem can lead to the constipation
becoming acute, which in some cases results in a trip to the ER.
Retrospective evaluation of risk factors and
treatment outcome predictors in cats presenting to the emergency room for
constipation (2020) Benjamin SE & Drobatz KJ Journal of
Feline Medicine and Surgery22(2) pp153-160 looked at cats
presenting to the ER with severe constipation and says "cats with
chronic kidney disease or previous episodes of constipation were found to
be at increased risk of constipation." Increased age or obesity were also
factors.
In addition to concentrating urine, a cat's body also tries to
conserve water by reabsorbing it from the stool through the intestinal
wall. This mechanism is very efficient, and remains so even in CKD cats,
and since CKD cats are largely on the edge of dehydration most of the
time, the intestine will wring every drop of water out of the stool that
it can, leaving it quite dry. The lack of moisture as a lubricant makes it
more difficult for the cat to have bowel movements and can lead to
constipation.
Constipation is sometimes caused by external factors,
e.g. if you put the litter tray up two flights of stairs and your elderly,
arthritic cat finds it hard to get up the stairs to it, or if the tray is
where your family dog can disturb the cat in the tray.
Survey of defecation habits in apparently healthy
and chronic kidney disease cats
(2022) Jones SE, Quimby JM, Summers SC, Adams SM, Caney SMA & Rudinsky AJ Journal
of Feline Medicine and Surgery24(2) pp131-141 states "Causes
include dehydration, electrolyte abnormalities, gastrointestinal
alterations and medications prescribed."
Symptoms
Some of the symptoms of constipation are pretty obvious, but others may come
as a surprise.
Pooping
Outside the Litter
Tray
Perhaps
next to it or you will find small bits of poop lying around the house.
This may also be a symptom of
cognitive dysfunction.
Vomiting
Before, During or Immediately After Using the Tray
Survey of defecation habits in apparently healthy
and chronic kidney disease cats
(2022) Jones SE, Quimby JM, Summers SC, Adams SM, Caney SMA & Rudinsky AJ Journal
of Feline Medicine and Surgery24(2) pp131-141 found
that "more cats in the CKD group showed signs of vomiting, vocalising and
straining around the time of defaecation."
Newman Veterinary mentions (scroll down
to Constipation) that
constipation may cause vomiting because
"stretch receptors within the serosa in the colon (or even serosal
surfaces of other abdominal viscera) respond to distension and transmit
signals to the vomit center of the brain inducing the vomit reflex."
Urinating Outside the Litter Tray
Most people
assume this is because of a urine-related problem (e.g. a urinary tract
infection) or a behavioural problem, but it can actually be a sign of
constipation. My Karma peed on the sofa so I took her to the vet for a suspected urinary tract
infection, but in fact she did not have one, her problem was constipation.
Once the constipation was under control, her inappropriate elimination
ceased.
The University of California at San Francisco
Department of Urology states "There is a close relationship between the muscles and nerves that
control bladder functions and those that control bowel movements. In
addition, the bladder and the colon are close together in the body.
Large amounts of stool in the colon can put pressure on the bladder
which can cause the bladder to not fill as much as it should, or cause
the bladder to contract when the bladder is not supposed to contract.
This large amount of stool can also cause the bladder to not empty well.
All of these problems can lead to daytime wetting, nighttime wetting,
urinary tract infections."
Diarrhoea
You see a
runny poop in the litter tray so you think (reasonably enough) that your
cat has diarrhoea but in fact the true problem is sometimes constipation, and the
runny stool is simply what can squeeze around the solid dry stool.
Frequent Visits to the Litter Tray
This may
sometimes be a sign of constipation but may also be a sign of a urinary
tract infection.
It may also be a sign of a very serious problem, i.e. the
inability to pass urine. I made this mistake myself with one of my cats
when I saw this symptom and thought he was constipated when in fact he had
a urinary tract blockage (luckily, despite my ignorance, I still got him to
the vet in time to save him).
If your cat cannot pass urine, this is a medical emergency and you need to
go to the vet immediately.
Fast
Breathing and Fast Heart Rate
One of my
cats
once had an episode of fast breathing and fast heart rate. He had severe
constipation, and his problems resolved once he had been given an enema.
If a cat is very severely constipated, toxins can back up in the cat's
system causing such problems; pain or discomfort can also cause fast
breathing, and severe constipation can be extremely uncomfortable. Alternatively you might see
lethargy and fainting, known as vasovagal syncope - syncope means to faint.
Medicine Net discusses this.
Obviously you do not want your cat to have such severe constipation that
these problems arise!
Frequent Visits to the
Litter Tray
Other possible symptoms include:
Dry and
hard stools
Straining
in the litter tray
Lying in
the litter box
Loss of appetite
An ungainly
walk
Here is a video from Dr Margie Scherk on how to recognise constipation in
your cat, courtesy of
DVM360.
Diagnosis
The vet can
usually feel the backed-up stool when s/he palpates the cat's abdomen, but
sometimes an x-ray is necessary to confirm the problem.
It can be helpful to know what normal stool looks like, so here are some links on the different colours, sizes and textures of cat
poop. I uploaded these just after eating a rather gooey chocolate brownie.
Bad move.
Emergency Vets USA discuss the meaning
of the different colours of cat poop.
Treatments
Which treatments you use depend largely upon how severe
your cat's problem is, and whether it is an acute problem or a chronic problem.
Acute problems will usually need treatment at the vet, but you should then
hopefully be able to maintain your cat at home with one or several of the treatments described
below.
If your cat has obstipation (i.e. the stool is impacted), your vet will have to remove the
stool for you.
Obviously you want to avoid the need for such treatments if at all
possible, but if they become
necessary, they do tend to work well and should make your cat much more
comfortable. You can then take steps to avoid the need for such treatments
in the future.
Since constipation is associated with dehydration, fluid therapy may help.
If your cat is receiving treatment for acute constipation at the vet's,
your vet may well put your cat on
intravenous fluids, or may give
a smaller amount of fluid
subcutaneously.
Suppositories
Paediatric suppositories containing only
glycerin are usually safe to give to cats, though of course check
with your vet first, and ideally ask your vet to teach
you how to give them.
I had to use a paediatric suppository on Harpsie
once when my vet was not available. It didn't work (he needed
veterinary treatment) but it was easier than I expected, and not stressful for
either of us.
Feline Constipation advises that if
you are using a liquid glycerin suppository, after you have squeezed
on the bulb to inject the suppository into your cat, you should keep
squeezing the bulb until you have removed the tip from your cat.
Some enemas are not safe to use in cats (see
Enema Cautions), but your vet will use one that is safe for your
cat.
Enemas can be messy so are normally given at the
vet's, but some members of Tanya's Support Group whose cats need
enemas regularly have been taught how to give them at home.
One
popular brand in the USA is Pet-Ema
6ml, which is designed especially for cats.
Constipation in cats
Duddy J Angell Medical Center says "Do not use enema solutions
containing sodium phosphate (Fleet) as they predispose to
life-threatening electrolyte imbalances (hypernatremia,
hyperphosphatemia and hypocalcemia)."
Troublesome toxicoses in cats
(2011) Dowers K Veterinary Medicine explains more
about this problem, including symptoms and treatment options should
a cat accidentally be given such an enema.
Manual Evacuation
If an enema does not work, the stool may be
impacted and have to be removed manually by your vet.
Water or
saline is introduced into the colon while the vet palpates the cat's
abdomen in order to break up the mass.
Feline constipation, obstipation and
megacolon: prevention, diagnosis and treatment (2001) Washabau R Presentation to the World Small Animal Veterinary Association
World Congress explains more about this and mentions that
it can be safer to do this over a period of several days.
Treatments for Chronic Constipation
If your cat has
constipation quite regularly, you want to control it as much as possible,
so as to prevent it reaching the stage where it needs veterinary help.
If your cat already has obstipation (i.e. the stool is impacted), your vet
will have to remove the stool for you, see
Acute Treatments,
and you can then try to maintain your cat at home. If you are ever
concerned though, always contact your vet.
If your cat is dehydrated, which is quite common with
CKD cats, getting the problem under control should help. Indeed, if you
don't ensure your cat is properly hydrated, the other treatments discussed
below will only be of limited use.
Chronic renal insufficiency and its
associated disorders kitty kidneys and the kitchen sink
(2007) Scherk M The 2007 Nestlé Purina Veterinary Symposium on
Companion Animal Medicine says "primary treatment should address
rehydration and the underlying cause of dehydration, rather than stool
passage (e.g., with laxatives). Promotility agents, laxatives, osmotic
agents, and fiber-enriched diets should be used only after the patient is
rehydrated."
Please ensure there are plenty of water drinking
opportunities available for your cat. Water fountains can be helpful. See
Oral Fluids for more
information.
Also consider feeding canned food in preference to dry
foods.
Most CKD cats will eventually be receiving sub-Q fluids
regularly to maintain hydration, and these may also help with
constipation. However, they are not normally given solely to assist with
constipation. Please see
Subcutaneous
Fluids for more information about this treatment.
Slippery Elm
Bark
Slippery elm bark is a natural treatment which can be sufficient to keep some
CKD cats regular; there
is more information on this treatment in
Holistic
Treatments.
Vitamin B12 (Methylcobalamin)
Some people whose cats have megacolon (a bowel
disorder which causes severe constipation) have found that giving
vitamin
B12 in the form of methylcobalamin is a helpful preventative
treatment.
Methylcobalamin is a popular choice for CKD cats too, and many people find
that it seems to help with constipation.
Fibre
Adding fibre to your cat's diet can help to bulk up the stool so that it
moves easily through the cat's system. Fibre-based treatments are intended
to help prevent constipation, but they cannot cure it once it is
present, so should not be used if the cat is blocked with faeces..
All bunged up unclogging the constipated cat
(2015) Scherk M Veterinary Medicine states "Moderately
fermentable fibers such as beet pulp are preferable to a highly
fermentable, high-gas-forming fiber source." See
Nutritional Requirements for more information on fibre, including beet
pulp.
Be careful if using additional fibre in diabetic cats, because fibre may
reduce blood sugar levels.
Some vets in the USA recommend a product called
Benefiber. This used to contain a type of fibre called guar gum, but it
now contains wheat dextrin. I think there are better choices available for
cats.
Fibre-Enriched Foods
I have heard
from a couple of people that a Royal Canin product,
Veterinary Diet Gastrointestinal Fiber Response
is helping with
their cats' constipation. I have not been able to obtain any information on its
phosphorus or protein levels as yet, but will try again. The people I have
heard from do not feed this food exclusively.
One vet told me that Hill's i/d food can help some cats. The canned
version contains 0.79% phosphorus and 40% protein on a dry matter
analysis, which are not unreasonable levels for most CKD cats.
Pumpkin and Other
Vegetables
Some forms of vegetables can be helpful for constipated cats. Popular
choices include pumpkin or squash or peas.
You can use canned pumpkin (not the pie filling) or canned peas (with no
additives). Many cats seem to quite like the taste of pumpkin, but different
brands can contain different types of pumpkin, and your cat may prefer one brand over another.
Some people have found Gerber's baby food pumpkin or squash helpful; it keeps
in the fridge for about two days.
If you cannot find canned pumpkin, you could
consider using Applaws Chicken & Pumpkin cat food and see if that helps. (I
have had no success ascertaining the phosphorus content of this food). There are a number
of other cat foods available containing pumpkin (see
Canned Foods USA), and
many of them seem to have reasonable levels of phosphorus, though
unfortunately they tend to have rather high levels of protein.
You do not need to cook the pumpkin if you buy the canned products listed below. You should start gradually, say with half a
teaspoon of pumpkin once or twice a day (it can be mixed with food), and
increase as needed.
If you buy fresh pumpkin, you will need to cook it before use.
The Pioneer Woman has an oven recipe, while
A Pinch of Healthy has instructions for
cooking it in an instant pot.
You can freeze unused pumpkin in ice cube trays and
just take out what you need for each day, though freezing it can change the
texture somewhat.
Pumpkin itself is low in
phosphorus. According to the USDA National Nutrient
Database, pumpkin cooked, boiled and drained without salt contains 0.48%
phosphorus on a dry matter analysis basis. Pumpkin canned without salt
contains 0.35% phosphorus on a dry matter analysis basis.
USA
In the USA canned pumpkin is usually widely
available in supermarkets, though there was a shortage in the summer of 2010.
Amazon sells Farmer's Market Organic Pumpkin
online, as well as pther brands, including Libby's.
Vitacost also sells Farmer's Market Organic
Pumpkin.
Amazon sells Raw Paws pumpkin powder, which may be easier to give
to your cat.
Tinned pumpkin can be harder to find in the UK, but
some branches of Waitrose and Sainsbury's sell American canned pumpkin with no
additives in the canned vegetables aisle.
Some people have found fresh cubed pumpkin is sometimes available, e.g. from
Marks and Spencer. This needs to be cooked before use.
In the USA psyllium is commonly sold under the name of Metamucil.
Drugs has some information about this. Be
sure not to buy Metamucil Clear and Natural (blue container) because this
does not contain psyllium.
You may prefer to buy a veterinary product such as
Vetasyl fiber capsules.
Drugs has some information about this
product. The usual dose is ½ to 1 capsule, depending upon the size of the
cat. The product can be mixed with food. I don't recommend Animal
Essentials Colon Rescue because it contains liquorice, which may raise
blood pressure.
In the UK, your vet may offer you a standardised pharmaceutical-grade fibre
called Nutrifyba.
Neals Yard Remedies
also sell
psyllium husks.
If you are using loose psyllium, you only need to give a tiny amount. The
maximum dose is ⅛th of a teaspoon, but you should start with an even
smaller dose.
With fibre-based treatments, it is very important to ensure that the cat
drinks plenty of water, otherwise the fibre can bulk up in the body and
make the constipation worse. Therefore if you mix it with your cat's
food, it is probably wise to add a little water too.
Be careful how you handle psyllium:
Psyllium: keeping this boon for patients from
becoming a bane for providers (2006) Hoffman D The Journal of Family
Practice55(9) pp770-772reports on the case of an
asthmatic nurse who died after inhaling psyllium powder, and recommends
spooning it rather than pouring it.
Too much fibre may prevent your cat from absorbing
sufficient nutrients or calories from his/her food. In humans,
some types of fibre may
also bind calcium in the small intestine and lead to an increase in calcium
levels in the body
(hypercalcaemia).
If you are only giving a small amount to prevent constipation, your cat will
probably be fine, but be careful if your cat already has hypercalcaemia.
Drugs states that
"Psyllium may interact with other medications if given at the same time.
This can cause your other medications to become less effective. In general,
all oral medications should be administered at least 2 hours before or 2
hours after dosing of psyllium."
PetCoach has some information about
psyllium use in cats.
Osmotic Laxatives: Polyethylene Glycol (PEG)
3350 (MiraLAX)
or Lactulose
These work by
drawing water into the stool, making it softer and easier for the cat to
pass. They are very effective treatments for most CKD cats, but for
optimum effect your cat should not be dehydrated.
Polyethylene glycol 3350, also known as PEG 3350, is an
osmotic laxative which is commonly used in cats. I am sometimes asked
about the name: polyethylene glycol 3350 is not
the same as ethylene glycol, an ingredient in
antifreeze which is toxic to cats.
Both PEG3350 and lactulose (see
below) are osmotic laxatives,
but unlike lactulose, PEG3350 retains water in the colon rather than pulling it
into the colon from the rest of the body.
The US National Library of Medicine
explains more about how it works.
Another advantage is
that it does not have the potential to cause
hypercalcaemia
(high calcium levels) which lactulose has, plus it is safe to give to
diabetic cats.
Since PEG3350 is available over the counter, you do not need a prescription
for it, though please do not use it without your vet's knowledge and
approval.
Polyethylene Glycol 3350
Formulations
MiraLAX is the
most widely known brand of PEG3350 in the USA. This is a human brand which
only contains PEG3350.
PEG3350 is often used in human patients to empty the
bowel before an endoscopy. If you use it for this purpose, it may cause an
imbalance in the body's electrolytes, particularly potassium and sodium.
Therefore some varieties of PEG3350 have added electrolytes to offset the
electrolyte imbalances which may result.
Since cats are not receiving PEG3350 for this purpose,
the added electrolytes are not necessary, and may not be appropriate for
CKD cats.
Safety and palatability of polyethylene glycol 3350
as an oral laxative in cats (2011) Tam FM, Carr AP and Myers SL
Journal of Feline Medicine and Surgery13 pp694-7 used a
version containing added electrolytes, and found that although it seemed to
be an effective laxative in cats, it did cause
increased potassium levels in some cats. These were not clinically
significant, but I would recommend trying to obtain PEG3350 without added
electrolytes if possible. If you have to use PEG3350 with added electrolytes, I would ask your vet to
monitor your cat's potassium levels.
Polyethylene Glycol 3350
Dosage
PEG3350 is a dose to effect medication.
Safety and palatability of polyethylene glycol 3350
as an oral laxative in cats (2011) Tam FM, Carr AP and Myers SL
Journal of Feline Medicine and Surgery13 pp694-7 says
"Effective doses varied widely in experimental cats, so individualized
dosing is important." Since your cat may respond well to the drug, it is
better to start off with a low dose and increase only as necessary.
Plumb's Veterinary Drug Handbook states "As a laxative
(extra-label): ⅛ to ¼ teaspoonful twice daily in food."
A common starting dose is ⅛ (one eighth) of a teaspoon
per day.
If you don't see an improvement in your cat's
constipation after three days, you can either give ⅛ of a teaspoon twice a
day, or increase to ¼ of a teaspoon once day.
If this doesn't work, consider giving ¼ of a teaspoon
twice per day.
If this still doesn't work, ask your vet about
increasing the dose.
In humans, PEG3350 is only supposed to be given for up
to seven days, but many humans and cats do use it on an ongoing basis.
Polyethylene Glycol 3350: How to Give
PEG3350 under the trade name of MiraLAX comes as an odourless and tasteless powder.
Plumb's Veterinary Drug Handbook says the "powder should be dissolved in liquid
before using."
MiraLAX can be mixed with water and given via a
dropper, though some people dissolve it in water and then mix it with baby
food or add it to their cat's canned food. Some people just sprinkle it on
their cat's food and mix it in.
It is not essential to give the day's dose once or
twice a day, you can divide it between your cat's meals over the course of
a day if you prefer.
Polyethylene Glycol 3350 and
Kidney Disease Warning
I have been asked why there is a warning on
MiraLAX stating that it should not be used in patients with renal failure,
particularly since this warning is not on generic products.
PEG3350 is often used to empty the bowel before an
endoscopy. If you use it for this purpose, it may cause an imbalance in
the body's electrolytes, particularly potassium and sodium. Since CKD
patients have a tendency towards electrolyte imbalances anyway, this could
be risky for a CKD patient. However, when giving PEG3350 to a CKD cat in
order to prevent constipation becoming a problem, you are using PEG3350 in
a different way which should not affect electrolytes in any way. But of
course do check with your vet before using PEG3350.
Feline constipation believes the warning
"is
a caution for humans with a tendency to self-diagnose and self-treat for
months without consulting with a doctor, humans who think if a little is
good, a lot is better. Provoking the Kitten equivalent of diarrhea by use
of any laxative causes water and electrolyte loss which can lead to
dehydration which is more risky for those with kidney disease than for
healthy individuals."
Polyethylene Glycol 3350 and
Other Safety Concerns
I sometimes hear from people who are concerned by
reports about the safety of PEG3350 when given to autistic children.
The FDA
investigated the concerns about PEG3350 and concluded "FDA decided that no action is necessary at this time based on available
information."
Autism speaks
has an interview with the gastroenterologist who
was quoted as having concerns about PEG3350 who says "Miralax remains the
most-effective medication for many children with autism and severe,
chronic constipation. So if you and your pediatrician have worked through
other approaches without success, I would still strongly consider using
Miralax based upon current safety information. At the same time, however,
I strongly recommend that the family and physician work together to find
the lowest effective dose. This is true with any stool softener or other
type of laxative."
I know of hundreds of cats who have used PEG3350 over
the years, some of them for years, and cannot recall any cats who had
problems with it. If you are concerned, talk to your vet about the best
way forward.
Polyethylene Glycol 3350: Interactions
Drugs
mentions a moderate interaction between cisapride, another treatment for
constipation (see
below) and PEG3350 which I
am sometimes asked about. The site states "cisapride can cause an
irregular heart rhythm that may be serious and potentially
life-threatening, although it is a relatively rare side effect. The risk
is increased if you have low blood levels of magnesium or potassium, which
can occur with bowel cleansing preparations or excessive use of
medications that have a laxative effect. Do not exceed the dose and
duration of use of polyethylene glycol 3350 recommended on the product
label or prescribed by your doctor."
This warning does not concern the ingredients in
PEG3350 but rather the fact that PEG3350, when used for bowel cleansing,
may also remove electrolytes such as
potassium, and this may
increase the potential risks of using cisapride. This will not apply to
most cats, who are using PEG3350 but not cisapride. Even if your cat is
receiving both medications, you are unlikely to be giving PEG3350 in high
enough doses for this to be a problem, but discuss with
your vet if you are using both products.
Polyethylene Glycol 3350 Sources
USA
MiraLAX is available without prescription in the USA,
so it is widely available from drugstores and supermarkets.
Generics are also available, but check that the product you wish to use
does not have added electrolytes (see
above).
Thriving Pets sells MiraLAX for
US$24.95. Smaller sizes are also available.
UK
MiraLAX is not available in the UK. Polyethylene glycol 3350 is widely available under the name of
Movicol. Unfortunately Movicol contains added
electrolytes (see
above).
MiraLAX used to be available on Amazon but no longer
seems to be available. Your best bet is probably eBay. Suppliers change,
but at the time of writing:
eBay has a seller offering 119g of MiraLAX for
£25 with free delivery.
Thriving Pets sell MiraLAX for US$24.95.
They will ship it to the UK but you will have to pay a customs paperwork fee of US$10,
and possibly a non US credit card fee of US$5. You will also have to pay
shipping and any import duties and taxes.
Canada
PEG3350 is sold in Canada under the name of
RestoraLAX or
Lax-A-Day, and is widely available in pharmacies.
Generics may also be available, but check that the product you wish to use
does not have added electrolytes (see
above).
Health Canada
reports that some RestoraLAX lots were recalled in July 2017. If
you bought your supplies before then, check
the link to see if your lot is affected.
Australia
PEG3350 is known as macrogol-3350 in Australia and should be
available in most pharmacies. Brand name include
OsmoLax and Movicol. Unfortunately, as in the UK, many
of these products seem to contain added electrolytes (see
above), though
the OsmoLax products appear to be safe (but double check the ingredients
before use).
VivaLAX appears to contain the active
ingredient only, but the product has disappeared from the manufacturer's
website, so I suspect it has been discontinued.
Lactulose is a
syrup of long chain indigestible sugars (derived from lactose, a milk
sugar) that pulls water into the colon and softens the stool.
The US National Library of Medicine explains
more about how it works.
Lactulose
and renal failure
(1997)
Vogt B & Frey FJ, Scandinavian Journal of Gastroenterology
Supplement222 pp100-1 indicated that lactulose may help
promote the excretion of BUN and creatinine through the faeces in humans.
A more recent study,
Lactulose for reduction of nitrogen products in
patients with chronic kidney disease
(2014)
Tayebi Khosroshahi H, Habibzadeh A, Khoshbaten M, Rahbari B, Chaichi P &
Badiee AH Iranian Journal of Kidney Disease8(5) pp377-381,
found that lactulose did reduce urea and creatinine levels in the human
patients in the study..
Some people have found that lactulose also reduced
creatinine levels in their CKD cats; but lactulose is not usually given specifically or solely for this purpose
because of the obvious side effects of causing diarrhoea in
non-constipated patients.
The
British Medical Journalreports on a 2001 study of human patients that indicates that lactulose
may also help to prevent urinary tract infections.
Lactulose is a "dose to effect" treatment, but as with any medication, it
is better to start with a low dose and increase only as necessary, so
as not to cause the opposite problem of diarrhoea.
Plumb's Veterinary Drug Handbook says that cats may be given 0.5ml per
kg (0.25ml per lb) of bodyweight per day up to 2-3 times daily. This would
mean a daily total of 1.0-1.5ml per kg or 0.5-1.0 ml per lb of bodyweight.
This means you would give a 5kg (11 lb) cat 5.0-7.5ml
daily.
Some people start at just 0.5ml (per cat) once a day, but this may
well need to be
adjusted depending upon the cat's response.
It does take a couple of days for lactulose to work, so do not give too
much too soon.
Lactulose: How to Give
I found out the hard way that, if you syringe lactulose in to your cat's
mouth, it's a good idea to wipe your cat's chin with a damp cloth after
using it, because, being sugar-based, it is incredibly sticky. You may
find it easier to mix the lactulose with food; some people use a little
baby food each day for this purpose.
Lactulose: Sources
Lactulose is available OTC in Europe, Canada and Australia (one brand in
Australia is
Duphalac), but it requires a
prescription in the USA.
Chewy sells lactulose for US$14.99 with
free shipping on orders over US$49.
Since lactulose is a prescription item in the
USA, it can be rather expensive, but Wal-Mart
and Target apparently both sell it for US$4 a bottle.
Kristalose
Kristalose is a powdered form of lactulose which can be dissolved in water,
which eliminates the stickiness problem found with standard lactulose.
Kristalose comes in packets of 10g and 20g. The 10g
packet contains 15 ml of lactulose.
Plumb's Veterinary Drug Handbook says that "one
gram of the crystals is equivalent to 1.5 mL of the liquid. An anecdotal
suggested dose for constipation in cats is ½ teaspoonful (2.5 ml) to ¾
teaspoonful (3.75 ml) twice daily."
This is a daily total of lactulose of 5.0-7.5ml a day.
This is in line with the standard lactulose dose for a
5kg (11lb) cat. If your cat is smaller than this, discuss with your vet,
because as discussed above, many cats may do fine on less than this.
As with MiraLAX, you should mix it with water before
giving.
If you are giving 7.5ml a day, a 10g packet would only
last two days. I heard from one person who used Kristalose for her cat, but she gave up because it was so expensive.
Some people have found that their cats developed
hypercalcaemia
(high calcium levels) after using lactulose regularly, which then improved
when they stopped using lactulose. The same issue arises in humans:
Effect of lactulose on calcium and magnesium
absorption: a study using stable isotopes in adult men
(2007) Seki N, Hamano H, Iiyama Y, Asano Y, Kokubo S, Yamauchi K,
Tamura Y, Uenishi K & Kudou H Journal of Nutritional Science &
Vitaminology (Tokyo)53(1) pp5-12 found that "lactulose enhance
the absorption of calcium and magnesium in adult men." You may therefore wish to avoid
lactulose if your cat is already hypercalcaemic.
Although lactulose is indigestible, it is
composed of sugar molecules,
so
Mar Vista Vet
advises against using it in
diabetic cats because it may raise blood sugar levels.
Drugs
mentions that there is a minor interaction between lactulose and
aluminium hydroxide (a phosphorus binder) which in theory may reduce the effectiveness of
lactulose when it is being used to treat a condition called hepatic encephalopathy. People
with CKD cats are normally using lactulose to treat constipation, not
hepatic encephalopathy, so this is unlikely to be a concern. Still, if you
are treating constipation caused by the use of aluminium hydroxide, and
are not finding lactulose to be as effective as you hoped, you could speak
to your vet about trying one of the other treatments discussed on this page instead.
Antibiotics may reduce the effectiveness of lactulose.
Lactulose may exacerbate the effects of
diuretics such as
furosemide.
Drugs
has more information about this, stating "Combining
these medications, especially over a prolonged period, may increase the
risk of dehydration and electrolyte abnormalities. In severe cases,
dehydration and electrolyte abnormalities can lead to irregular heart
rhythm, seizures, and kidney problems."
I have heard from a couple of people who found that their IBD cats did not
seem to do too well on
lactulose. This may be because, as mentioned in
Update on the non-invasive monitoring of intestinal
disease in dogs and cats (2000) Batt R Revue Médicine
Véterinaire151(7) pp559-563, more lactulose is absorbed by a
damaged gut than by a healthy one. If your IBD cat seems to worsen on
lactulose, speak to your vet about switching to another treatment.
Prokinetic
Medications
Most CKD cats
with constipation will respond to the treatments outlined above, but some
cats may need a medication for reduced motility. Such medications help
stimulate contractions in the colon to move the stool.
Cisapride is another medication used for cats with
constipation caused by reduced motility. Trade names are Prepulsid or
Propulsid.
Cisapride works by activating certain muscle receptors.
Constipation and obstipation in small animals
(2020) Defarges A Merck Veterinary Manual
says "Anecdotal
experience suggest that cisapride
(0.1–0.5 mg/kg, PO, bid-tid) effectively stimulates colonic propulsive
motility in cats with mild to moderate idiopathic constipation."
According to
RxList, cisapride was withdrawn from the human market
in 2000 because of serious heart-related side effects which caused some human
deaths.
However, cisapride appears to be safe to use in cats.
Constipation and obstipation in small animals
(2020) Defarges A Merck Veterinary Manual
says "No significant adverse effects have been reported in cats
treated with cisapride at
dosages of 0.1–1 mg/kg, PO, bid-tid)." Plumb's Veterinary Drug Handbook
states "Adverse effects appear to be minimal in veterinary patients;
vomiting, diarrhea, and abdominal discomfort can occur." It does add
"Although no reports have been noted in dogs or cats, prolonged QT
intervals or other cardiac arrhythmias are possible but unlikely." You may
wish to avoid cisapride if your cat has heart problems.
Dosage recommendations are as follows:
Constipation and obstipation in small animals
(2020) Defarges A Merck Veterinary Manual
says "Anecdotal
experience suggest that cisapride
(0.1–0.5 mg/kg, PO, bid-tid):" bid-tid means 2-3 times a day.
Plumb's Veterinary Drug Handbook says:
"As a promotility agent (extra-label): Initially, 2.5 mg per cat PO twice
daily preferably 15-30 minutes before food. Dosages may be titrated
upwards, if tolerated, to as high as 7.5 mg per cat PO 3 times daily in
large cats."
Cisapride can take time to work. Plumb's Veterinary
Drug Handbook does mention that it can be given in conjunction with
lactulose,
psyllium or
pumpkin, so you can continue
to use these treatments while waiting for cisapride to work.
Because cisapride was withdrawn from the human market
in the USA, cisapride is only available from
compounding pharmacies in the USA, though it may be possible to obtain it
commercially in other countries.
Chewy sells cisapride in the USA in the
form of compounded soft chews for cats.
Cisapride interacts with a number of medications,
including
cimetidine (sometimes used in CKD cats for gastric hyperacidity), which according to Plumb's Veterinary Drug Handbook "may
lead to increased cisapride levels with an increased risk for cisapride
cardiotoxicity," and benzodiazepines such as
diazepam (Valium), the effects of which may be made stronger. It also
reduces the effects of
ranitidine, but since both medications have similar mechanisms, you
are unlikely to be giving both cisapride and ranitidine for constipation.
Drugs
mentions a moderate interaction between cisapride and
PEG3350 (MiraLAX) which I am
sometimes asked about. The site states "cisapride can cause an irregular
heart rhythm that may be serious and potentially life-threatening,
although it is a relatively rare side effect. The risk is increased if you
have low blood levels of magnesium or potassium, which can occur with
bowel cleansing preparations or excessive use of medications that have a
laxative effect. Do not exceed the dose and duration of use of
polyethylene glycol 3350 recommended on the product label or prescribed by
your doctor." This warning does not concern the ingredients in
PEG3350 but rather the fact that PEG3350, when used for bowel cleansing,
may also remove electrolytes such as
potassium, and this may
increase the potential risks of using cisapride. This will not apply to
most people using PEG3350 to control constipation in their cats, but discuss with
your vet if you are using both products.
Ondansetron is often used in CKD cats to control nausea. However,
Drugs states
that "Using cisapride together with ondansetron is not recommended.
Combining these medications can increase the risk of an irregular heart
rhythm that may be serious and potentially life-threatening, although it
is a relatively rare side effect." This warning applies to humans, but
check with your vet if you need to use both these medications.
Ranitidine
(Zantac 75)
Ranitidine
(Zantac 75) was commonly used to help treat gastric hyperacidity in CKD cats.
However, it may also help with constipation caused by low motility in the
colon, so was a popular choice for cats needing treatment for both
constipation and gastric hyperacidity.
Feline constipation, obstipation and megacolon:
prevention, diagnosis and treatment (2001) Washabau R Presentation to the World Small Animal Veterinary Association
World Congress has information about this effect of
ranitidine.
However, on 1 April 2020 the
US Food & Drug Administration requested
the removal of all ranitidine products from the market with immediate
effect, because it may contain a carcinogenic (cancer-causing) ingredient
called N-nitrosodimethylamin (NDMA). This means ranitidine will not be available in any form in the
USA, and many other countries are taking the same approach. The FDA
further advises that you should not use any ranitidine which you currently
have in your possession.
Constipation
Cautions
I don't
recommend hairball remedies because they tend not to be particularly
effective for chronically constipated CKD cats. I don't recommend mineral
oil because it can be downright dangerous.
Many vets seem to routinely prescribe hairball remedies such as Laxatone or Petromalt, but
these are really intended for the treatment of hairballs. These products
may be of some limited use if given for a short period to try and soften
the hard stool often seen at initial diagnosis prior to using other
treatment methods. However, they are not ideal
— or particularly effective — for the ongoing constipation problems
suffered by many CKD cats.
Feline constipation
Duddy J Angell Medical Center says "Hairball remedies are only advised in
very mild cases of constipation."
In addition, these products may prevent
the absorption of nutrients if used longer-term.
PetCoach
(search for hairball remedies and laxatives if necessary) ays "May see a decrease in the absorption of fat-soluble vitamins
(A, D, E, & K) when used frequently and long term."
Mineral Oil
Mineral oil (liquid paraffin) should not be
used, because since it has no smell or taste, it can easily be
aspirated and cause pneumonia.
Constipation and obstipation in small animals
(2020) Defarges A Merck Veterinary Manual
says "Mineral
oil use should be limited to rectal administration because of the
risk of aspiration pneumonia with oral administration."
Pet Place
has more information on
aspiration pneumonia.
TREATING YOUR CAT WITHOUT VETERINARY ADVICE CAN BE
EXTREMELY DANGEROUS.
I have
tried very hard to ensure that the information provided in this website is
accurate, but I am NOT a vet, just an ordinary person who has lived
through CKD with three cats. This website is for educational purposes
only, and is not intended to be used to diagnose or treat any cat. Before
trying any of the treatments described herein, you MUST consult a
qualified veterinarian and obtain professional advice on the correct
regimen for your cat and his or her particular requirements; and you
should only use any treatments described here with the full knowledge and
approval of your vet. No responsibility can be accepted.
If your cat
appears to be in pain or distress, do not waste time on the internet,
contact your vet immediately.
This site was
created using Microsoft software, and therefore it is best viewed in
Internet Explorer. I know it doesn't always display too well in other
browsers, but I'm not an IT expert so I'm afraid I don't know how to
change that. I would love it to display perfectly everywhere, but my focus
is on making the information available. When I get time, I'll try to
improve how it displays in other browsers.
This site is a labour of love, from which I do not make
a penny. Please do not steal from me by taking credit for my work.
If you wish to
link to this site, please feel free to do so. Please make it clear that
this is a link and not your own work. I would appreciate being informed of
your link.
