E-mail Comments from Veterinarians

From Tony Lopez, DVM, Diplomate, American Board of Veterinary Practitioners (Canine and Feline Practice), Phillips Creek Veterinary Hospital
Dallas, TX: 

Sent: Fri 8/15/2008 6:43 PM

I do use calcitriol and ace inhibitors routinely in both cats and dogs.   I believe that the evidence is stronger for the benefits of calcitriol in dogs versus cats, but while the evidence is still lacking, I think there is enough anecdotal evidence and/or research in the human and canine areas to warrant its use in cats.  I personally feel that it helps cats and dogs feel better for longer, and since PTH (which is what you are effectively trying to lower with calcitriol) is known to be a uremic toxin, it only makes sense that this is the case.  I think there is a positive benefit and owners are usually interested if they are interested in other options for CKD management. 

I do recommend taking care of other issues first, such as evaluating for hypertension, urine protein, ruling out UTI’s with cultures, and making sure that nutritional needs are being met with a renal prescription food and adjunct phosphorus binders if necessary to control phosphorus levels.  Once that is complete, I recommend calcitriol if an owner is willing to do it from the earliest signs of renal insufficiency (even just dilute urine on cats).  I have used and am using it in many, many cats and dogs and have yet to see any adverse effects.  Unfortunately, until there are double blinded, randomized, controlled studies with a good number of cats (and dogs), we just won’t be able to say for sure what the actual benefit is in fact.  I do find the product easy to obtain and prescribe through Franck’s Compounding pharmacy [Franck's closed in September 2012] in Florida (800.622.4510).  I use this pharmacy only because of Dr. Nagode’s and other experts recommendations as to the quality.  I generally just fax in a prescription and let the owner call and make payment/shipping arrangements.  Cost is generally acceptable and reasonable.  Monitoring needs to be done for PTH levels, calcium levels, and phosphorus levels.  I have not had any problem getting what seem to be reliable test results on the PTH and/or ionized calcium, and phosphorus.  The testing necessary does add to the cost issue for some owners.



From Amy Lynn, DVM, Internal Medicine Specialist, Michigan Veterinary Specialists, Southfield and Auburn Hills, Michigan:

Sent: Sunday, March 16, 2008 7:58 PM

As you are aware, the use of calcitriol for CRD is still considered rather "controversial". I have not used it yet on a patient, but there is certainly a growing body of evidence supporting its use, and I'm sure I'll eventually prescribe it for a CRD cat. Once again, careful patient selection and close monitoring is essential. I heard Dr. Chew speak last fall on the topic, and he certainly made some very valid points.

Best wishes,

Amy Lynn, DVM

From Sarah M. A. Caney, BVSc, PhD, DSAM (Feline), MRCVS, proprietor of The Cat Professional Web Site, and author of the 2008 book "Caring for a cat with kidney failure:"

Sent: Tuesday, February 19, 2008 7:14 AM

Calcitriol: Calcitriol is not a widely used therapy in the UK (where I am based) which is for a few reasons. Measurement of parathyroid hormone levels is very expensive and technically demanding from a sample handling perspective (the sample needs to be sent frozen and very quickly to the lab) which is off-putting to vets and their clients. Calcitriol is not easy to get hold of for patients – there are very few compounding pharmacies in the UK and these are also very expensive. Also, there is still only anecdotal evidence to support the use of this drug in cats with renal failure – no well designed, placebo controlled studies have been published to support the use of calcitriol in cats. This doesn’t mean that it doesn’t work – it may well help a number of cats – but it has meant that it is not a commonly adopted treatment in the UK. 

I hope that this is of help to your website ... Thanks for getting in touch.

Yours sincerely,

Sarah Caney

From Arnold Plotnick MS, DVM, ACVIM, ABVP (Feline Practice) and owner of Manhattan Cats Specialists in New York, NY:

Sent: Tuesday, February 12, 2008 2:08 PM

I have very little experience with calcitriol.  As I’m sure you know, the idea behind using calcitriol is to suppress the secretion of PTH from the parathyroid gland, as PTH is believed to be detrimental to cats with CRF. There are several reasons why calcitriol isn’t used very often, I believe. One reason is that PTH isn’t very easy to measure. The sampling requirements are a little cumbersome, and the test is a bit pricey.  The second reason is that calcitriol isn’t available as a commercial product in a convenient cat size.  You have to order it special from a compounding pharmacy.  Not a big deal, but some vets are probably unwilling to bother.  A third reason is that it involves diligent monitoring.  You have to make sure the phosphorus level is low before you give it.  You have to make sure that the calcium level doesn’t get too high after you give it.  The monitoring is labor intensive, and a lot of vets probably believe that their clients won’t be too thrilled with the time commitment and financial commitment involved. 

Not too long ago, in the Journal of Veterinary Internal Medicine, a report on the use of calcitriol in cats with CRF and elevated PTH levels surprisingly revealed that the calcitriol was ineffective. In that study, 10 cats with high PTH levels were given calcitriol expected to lower the PTH levels, but it did not lower the levels.  The dosage used was the same as that which has been used in dogs.  Perhaps this dose was too little?  No one can be sure yet. 

Arnold Plotnick

From Bob Vasilopulos, DVM, MS, DACVIM, Internal Medicine specialist for the Premier Veterinary Group  and Internal Medicine Consultant for the Veterinary Information Network (VIN)

Sent: Monday, February 11, 2008 3:58 PM

I have to admit, I was skeptical at first with the use of calcitriol in the treatment of hyperparathyroidism secondary to chronic renal failure in veterinary medicine mainly due to the lack of controlled studies supporting its benefit and experts cautioning against its use.  I started to routinely offer calcitriol in early renal failure only after two respected colleagues, Drs. Sherri Williams and Alice Wolf, were so adamant regarding its benefits in their patients.  Since then, I have seen many dogs and cats improve clinically --with their owners reporting improved activity, appetite, and quality of life, after starting calcitriol therapy.  Until a cure for chronic renal failure is discovered, our main goal is to offer treatments to improve the quality as well as the quantity of life for these beloved pets.  I now am a proponent for the use of calcitriol in chronic renal failure.

Controlled studies would surely be a welcome addition to the veterinary literature regarding the benefits of calcitriol's use but owner testimonials and support from other respected veterinary specialists are a good place to start.


From Dan Cirnigliaro, DVM, Dr. Dan's Acorn Acres Cat Hospital, Hudson, NH

Sent:  February 4, 2008

I am Dr Daniel A Cirnigliaro DVM and I own Dr Dan’s Acorn Acres Cat Hospital in Hudson NH. I have no fancy initials behind my name just 21 years of hard knocks in the trenches treatment of chronic diseases in my practice. Chronic renal disease is by far one of the most common and often frustrating conditions I see in my older feline patients. 

Our approach to therapy has always been a balanced one; working with diets, supplements, medications, fluids and in the last few years Calcitriol. I have been amazed at how well my patients have done when we have added Calcitriol to their therapy. I cannot say that we have slowed the progress of the disease but we certainly make the patients feel better. To me quality of life is the end point of all therapies. A patient’s life quality must be maintained or increased for a treatment to be a success and Calcitriol has succeeded in that. I have to thank Dr. Larry Nagode and his posts on VIN for teaching me about this therapy. No CRF patient will leave my practice without at least being offered Calcitriol as part of their therapy. 


From Dr. Elizabeth J. Colleran, DVM, MS, owner of Chico Hospital for Cats in Chico, CA, and the Cat Hospital of Portland in Portland, OR, and 2008 Secretary-Treasurer of the American Association of Feline Practitioners (AAFP).

Sent: Thursday, February 07, 2008 11:29 AM
To: David Jacobson

We have two feline exclusive veterinary practices, one in CA and one in Portland OR. Calcitriol has become a mainstay of treatment for our cats with CRI. We start them as early as their disease is recognized and Phosphorus is normalized. Our best results have come with cats whose Creatinine is still 2.0 or near that but they are isosthenuric. We put them on their calculated dose of Calcitriol (3ng/Kg) and monitor serum Ca. on Day 7 and 14 of therapy. If it is normal we continue therapy for 60 days and recheck all the renal parameters. I have not experienced a single case that has not benefited by this supplement. They eat better, feel better, and often Creatinine levels improve some. However, they remain isosthenuric. So we don't cure their disease, just slow it down and make them feel better.


From Sherri Wilson, DVM, Diplomate ACVIM (Internal Medicine), Internal Medicine Consultant for the Veterinary Information Network (VIN).

Chronic renal failure is a major problem in older cats and dogs. Unfortunately, very few treatments change the progression of the disease, so it becomes especially important to control the few things that can prolong survival. Among these interventions would be monitoring for urinary tract infection, monitoring for hypertension, and controlling parathyroid hormone levels. 

Calcitriol is the key to controlling hyperparathyroidism. When it's used early in renal failure, the dose that will be effective is predictable and less expensive monitoring is necessary. This is the best use of the drug -- to start it before the parathyroid hormone levels increase. However, it's never too late in the progression of renal failure to start it -- but starting later means the dose of calcitriol is less predictable, so more monitoring of parathyroid hormone levels is required. In addition, starting later usually means that we have to work first to make the phosphorus level drop below 6.0 mg/dl -- calcitriol physically can't work when the phosphorus level is higher. To do this requires a combination of a low protein (also low in phosphorus) diet, and frequently the use of aluminum hydroxide (trade names Amphogel, Alternagel, Basaljel) to bind phosphorus in the diet. Once the phosphorus level drops, then usually the phosphate binder isn't required for the long run.

Not only is calcitriol working silently to prolong survival, but it actually causes the animal to feel better--better appetite and more activity. 

In the veterinary literature, some confusion has been caused by the publication of opinions by a particular group of nephrologists who feel strongly that calcitriol is dangerous in renal failure animals. This opinion is based on their interpretation of studies they performed using calcitriol--they used high doses of calcitriol, and repeatedly caused the animals to have high serum calcium levels. Indeed, if you use calcitriol at those doses, that is a major risk, and hypercalcemia is detrimental to kidney function. However, those doses of calcitriol are not being used to control renal secondary hyperparathyroidism -- we can control parathyroid hormone effectively with doses ranging from 1/3-1/4 of those high doses, thus making the drug very safe. Some monitoring is required of calcium and phosphorus levels, but renal damage is not seen ... in fact the opposite is true ... renal function is spared. 

From William R. Folger, DVM, dipABVP (Feline Practice), Owner of Memorial Cat Hospital in Houston, TX, Internal Medicine (Feline) Consultant for the Veterinary Information Network (VIN).

Sent: November 1, 2005

Calcitriol is an effective adjunctive therapy for chronic renal disease in cats. We routinely begin calcitriol therapy as soon as azotemia develops. All of our clients have reported similar experiences: their cat feels better, is more active, and has an improved appetite. All of these contribute to an enhanced quality of life for our geriatric felines.  I consider calcitriol to most important  clinical advance in chronic renal disease therapy since the advent of erythropoetin therapy for anemia in these cats. Calcitriol, phosphate binders, erythropoetin, appetite stimulants,  potassium supplementation, subcutaneous fluid therapy: these are the current cornerstones of medical therapy for chronic renal disease in the feline. 

From Kim Schiller, DVM, dipABVP (Canine/Feline Practice), owner of Colvet Run Veterinary Clinic in Vienna, Virginia, and internal medicine consultant for the Veterinary Information Network (VIN):

Sent:  February 2003

I have treated quite a few cats and have been pleased with what I have seen.  The problem with calcitriol is there haven't been good controlled studies to this point and many are reluctant to use it because of this.  Additionally, there has been some work to suggest its utility in the treatment of CRF cats but some of the data was misinterpreted by some.  I will continue to use it whenever I have a CRF cat presented to me.   (

From Sandra Coon, DVM, owner of Broadway Veterinary Hospital and Laser Surgery Center in Seattle, Washington:

Sent:  December 4, 2002

In September 1993 I was presented with my first patient that was being treated with calcitriol. This adorable elderly cat named Deluxe had been diagnosed with CRF three years earlier and had entered into a study using calcitriol with Dr. Nagode at Ohio State University. At the time I was very impressed with at Deluxe’s longevity and vigor. At that time I had never seen a cat with that level of kidney failure live so long and with good quality ! of life. Before using calcitriol I would have expected Deluxe to live 9 to 18 months after diagnosis. Deluxe lived an additional nine months and died of an unrelated disease condition, thus Deluxe lived almost twice as long I could have hoped for. 

I am thrilled to have a calcitriol to offer clients with CRF pets. Calcitriol is an easily administered, effective medication that has the potential to substantially increase longevity and quality of life especially when used early in the course of disease. In our practice every client with a pet diagnosed with CRF is introduced to the idea of using calcitriol. While it is not the right choice for every client and pet it is a very useful and beneficial medication for many pets with chronic kidney failure. When my own sixteen-year-old dog, love of my life, developed kidney failure she started on the preventive low dose calcitriol protocol.

Sandra Coon,

From Joe Whalen, DVM, LePar Animal Hospital, Evergreen Park, IL:

Sent:  November 30, 2002

I will summarize my experience with calcitriol.  Since December of 1994 I have filled 643 feline prescriptions and 80 canine prescriptions for calcitriol. These prescriptions have mostly been for 60 day treatment lengths for cats and 100 day treatment lengths for dogs.  Calcitriol in all these cases was prescribed for CRF cases in which the phosphorus was below 6.0. The dose for calcitriol was 2.5 mg/kg.  Calcitriol was stopped when the serum phosphorus levels rose above 6.0, when hypercalcemia developed, when it was not tolerated by the pet (rare), or the owner was unable to give (rare, also).

After reviewing Drs. Nagode and Chew’s protocol for calcitriol use on your website I must admit that my patient monitoring of PTH levels and adjusting of calcitriol doses has been very limited.

Having said this, I believe calcitriol is an important addition to early CRF treatments. I always try dietary therapy but as we all know this is hit or miss, especially with cats.  The control of hypertension and oral potassium supplements when appropriate are very important therapies as well.  I would estimate that at least 25% of the CRF cats that I see are not hypertensive and won’t eat a therapeutic diet or any food with potassium added (or the owners are unwilling to pill).  In this subpopulation of cats calcitriol may be your only hope of slowing down the progression of CRF (short of fluid therapy).  Clinically, I have seen many cats improve on calcitriol only.  Weight gain and improved appetites and activity levels are the most common changes noted.  Creatinine and BUN levels often stabilize and sometimes improve.  In general practice I believe the two most underused CRF therapies are the use of calcitriol and the control of hypertension.

Joe Whalen, DVM

From Wendy C. Brooks DVM, dipABVP, Educational Director for VeterinaryPartner.com and owner of Mar Vista Animal Medical Center in Los Angeles, California:

Sent August 12, 2002

I remember when calcitriol was just a new thing some people at OSU were studying. One of my internmates was in charge of the University Emergency Service and had a renal kitty and was very interested in calcitriol information and passed it on to me.  When I first added calcitriol to my standard therapy for renal kitties I could not believe the results. The survival time increased. For the first time I got kitties who actually could go off SQ fluids after having been on them for months. I see a big prognostic difference in the kitties who are candidates for calcitriol (phosphorus level still normal) and those who are not candidates (phosphorus too high). When we get a cat to cross groups with fluid therapy, diet or whatever, we see the same good results as with the cats who had been on calcitriol from the beginning. I know this is subjective  (after all, I am just treating cats in practice, not conducting a research study) but I think the advent of Calcitriol has been one of the biggest breakthroughs in the management of renal disease in the cat.

This web page is a product of me, David Jacobson, and is maintained for members of the Feline Calcitriol User group, veterinarians, cat and dogs owners, and others interested in the use of compounded calcitriol to treat cats and dogs with chronic renal disease (CRD).  My thanks to Drs. Larry Nagode and Dennis Chew for allowing me to post their professional work here and to Dr. Nagode assistance in creating this site.   If you are now using or have used calcitriol to treat your own CRF pet, please email me your personal story for posting here!  Your comments, suggestions and criticisms about this site are welcome and appreciated. 
David Jacobson, Arlington, VA