Tuesday, July 22, 2014

Dr. Peterson Interviewed for Dog Fancy Article About Insulin Pen for Dogs

Dr. Peterson was interviewed for the September 2014 issue of Dog Fancy (pictured above). Merck Animal Health has just received approval from the FDA to sell their VetPen product, the first insulin injection pen available for diabetic dogs and cats, and Dr. Peterson weighed in on the benefits of such an easy-to-use device.

Monday, May 26, 2014

Celebrate the Seventh Annual World Thyroid Day

It's not just cats and dogs that develop thyroid disease. Approximately 750 million people worldwide are affected by thyroid disorders, and the Seventh Annual World Thyroid Day, being held this weekend, has 5 major goals, say the organizations who support it. These include the American Thyroid Association (ATA), the European Thyroid Association, the Asia Oceania Thyroid Association, and the Latin American Thyroid Society.

The thyroid gland produces hormones that regulate the body's metabolism and influence every cell, tissue, and organ in the body, they point out. Hypothyroidism is characterized by symptoms of fatigue, depression, and forgetfulness, while hyperthyroidism is associated with irritability, nervousness, and muscle weakness.

The aims of World Thyroid Day are the following:
  • Increase awareness of thyroid health. 
  • Promote understanding of advances made in treating thyroid diseases. 
  • Emphasize the prevalence of thyroid diseases. 
  • Focus on the urgent need for education and prevention programs.
  • Expand awareness of new treatment modalities.
The thyroid gland, butterfly-shaped and located in the middle of the lower neck, produces hormones that influence every cell, tissue and organ in the body. The thyroid hormones regulate the body's metabolism—the rate at which the body produces energy from nutrients and oxygen—and affects critical body functions, such as energy level and heart rate.

The thyroid also plays a critical role during pregnancy, the thyroid societies explain. Consequently, the ATA recommends that pregnant women at high risk for thyroid disease should have their thyroid function tested early in their pregnancy. Another important issue is thyroid cancer, which is rapidly increasing, according to the ATA, which says there were 44,670 new cases of thyroid cancer recorded in 2010 in the United States.

But when thyroid cancer is identified and treated early, "the majority of patients can be completely cured," the American Thyroid Association stresses. The organization also notes that it is important to distinguish thyroid cancer from benign thyroid nodules, which are common in the population.

Patient education on human thyroid conditions can be found on the ATA website at http://www.thyroid.org/patient-thyroid-information/.

Thursday, May 22, 2014

Insect Repellent, Antiviral Drug Detected in Jerky Pet Treats for Dogs

Chicken jerky treats consumed by dogs that became sick over the past few month have now been found to be tainted by the insect repellent N,N-diethyl-meta-toluamide, better known as DEET, as well as the antiviral drug amantadine.

This is according to a veterinary pathologist leading an independent probe of the ongoing pet treat mystery.  For more information, click this link to read the article by the Veterinary Information Network News Service.

Friday, April 4, 2014

Insulin Injection Pen (VetPen): More Questions (and Answers) about this New Diabetic Product

Since the FDA approved the use of a new insulin injection pen (VetPen) made by Merck Animal Health last week (1,2), I've received a number of questions from both veterinarians and owners of diabetic pets. Listed below are some of the most common questions with my responses.

Do we buy a single VetPen and use it forever? Or does the VetPen have to be replaced after a month or two?

The VetPen has been tested for at least 3,000 actuations (i.e., how many times the insulin release button is pressed and released). Therefore, a single VetPen is likely to last a lifetime for the majority of dogs and cats treated with diabetes.

How are the pens and cartridges sold? 
The reusable VetPen is supplied in a Starter Kit which contains everything you need to get started (see below). This included everything except the Vetsulin cartridges, which are supplied separately in cartons of ten, 2.7-mL cartridges.

The VetPen itself is available in 2 sizes. For greater accuracy at low doses, the first option (blue cap) has a maximum total dose of 8 units, allowing for dosing increments of 0.5 unit per injection. If higher insulin doses are being administered, the second VetPen option (tan cap) has a maximum total dose of 16 IU per injection, with dosing increments of 1 unit.

What is in each VetPen Starter Kit?
Each Starter Kit contains either an 8-unit or 16-unit VetPen with an instruction leaflet.

The kit also contains a box of 28-g, ultra-thin needles that feature a silicone coating to help minimize injection discomfort, as well as a needle remover that helps to remove used needles, while minimizing the risk of accidental needle stick injury. There is also a travel pouch to hold all of the components.

The kit also contains two adaptors to assist those with dexterity issues. The dose selector adaptor may be used to provide a better grip when selecting a dose. The release button extension may be used to provide a better grip when giving injections.

Are the VetPens an accurate way for insulin dosing?
The VetPen is ideal for cats and small dogs on low doses of insulin, in which dosing accuracy can be a concern (3,4). A recent study comparing the precision and accuracy of the VetPen to U40 syringes demonstrated that even when doses were drawn up by trained laboratory technicians, syringes were found to deliver at least 20% to 25% more insulin than needed for a 1-unit dose (5).

In contrast, VetPen enables doses to be delivered with accuracy and precision down to 0.5 units. In large dogs, dosing accuracy is generally not a problem.

Do the pens and cartridge need to be refrigerated? Other handling precautions?
The VetPen cartridges should be refrigerated (not frozen) and protected from light before opening.

VetPen does not need to be refrigerated after a cartridge has been started (4), although it probably is best to do so. The loaded VetPen can be stored on its side in the refrigerator.

VetPen should always be stored or carried with the needle removed and the cap on. To clean the device, wipe with a damp cloth. Do not immerse in water.

Are the VetPens expensive? How would the costs of the VetPen compare to those associated with the standard insulin vial/syringe method?

The cost of treatment will depend upon the size of the diabetic pet. For smaller dogs and cats, the price of the VetPen with the Vetsulin cartridges and needles will be similar to the cost of the standard 10-mL Vetsulin vial and U-40 insulin syringes.   For larger dogs, the standard way of administering Vetsulin (via an insulin syringe) would generally be a more economical way to provide insulin treatment.

Bottom Line:

These insulin pen devices are an alternative to the traditional insulin vial-and-syringe method and offer many advantages. In human diabetic patients, insulin pens have also been found to be less painful than the vial-and-syringe method and are often associated with greater patient preference and social acceptability (6-11).  Similar preliminary findings have been documented in dogs and cats (12,13). As a result, this method of insulin delivery may ultimately help to improve glycemic control and should be considered as an alternative insulin delivery method.

Insulin pens are designed to deliver a fixed insulin dose while insulin syringes rely on the ability of the user to accurately draw up the required insulin dose. One recent study reported that for low doses (below 8 units), the VetPens were more precise and accurate than the insulin syringes (5). In particular, insulin syringes tend to over-deliver, compared to the insulin pen, for very low doses (1 unit). For higher doses (16 units), both devices were comparable (5).

Similar findings have been reported in human pediatric patients, in which very low doses of insulin must be administered. One older study looked at the reliability of using U100 syringes for accurately administering low doses of insulin in the hospital by pediatric nurses. In that study, attempts to administer doses of 0.5 U or 1.0 U of U-100 insulin resulted in overdosage of 95% and 66%, respectively (14). Based on this study, it's no wonder that small diabetic dogs or cats are often a challenge to regulate when small insulin doses are needed.

  1. FDA website. FDA Approves First Insulin Product for Use with Automatic Injection Pen in Cats and Dogs.
  2. Press release. Merck Animal Health Receives FDA Approval of VetPen  
  3. Merck Caninsulin website. Caninsulin® VetPen® helps make pet diabetes management easier 
  4. Pet Diabetes website. What you need to know about the Caninsulin VetPen
  5. Burgaud S, Riant S, Piau N. Comparative laboratory evaluation of dose delivery using a veterinary insulin pen. Proceedings World Congress ASAVA/FECAVA/BSAVA 2012;567.
  6. Molife C, Lee LJ, Shi L, et al. Assessment of patient-reported outcomes of insulin pen devices versus conventional vial and syringe. Diabetes Technol Ther 2009;11:529-538. 
  7. Pearson TL. Practical aspects of insulin pen devices. J Diabetes Sci Technol 2010;4:522-531. 
  8. Wright BM, Bellone JM, McCoy EK. A review of insulin pen devices and use in the elderly diabetic population. Clin Med Insights Endocrinol Diabetes 2010;3:53-63. 
  9. Cuddihy RM, Borgman SK. Considerations for diabetes: treatment with insulin pen devices. Am J Ther 2013;20:694-702. 
  10. Davis EM, Foral PA, Dull RB, et al. Review of insulin therapy and pen use in hospitalized patients. Hosp Pharm 2013;48:396-405. 
  11. McCoy EK, Wright BM. A review of insulin pen devices. Postgrad Med 2010;122:81-88. 
  12. Burgaud S, Guillot R, Harnois-Milon G. Clinical evaluation of a veterinary insulin pen in diabetic cats. Proceedings World Congress ASAVA/FECAVA/BSAVA 2012;499.
  13. Burgaud S, Guillot R, Harnois-Milon G. Clinical evaluation of a veterinary insulin pen in diabetic dogs. Proceedings World Congress ASAVA/FECAVA/BSAVA 2012;568.
  14. Casella SJ, Mongilio MK, Plotnick LP, et al. Accuracy and precision of low-dose insulin administration. Pediatrics 1993;91:1155-1157. 

Wednesday, March 19, 2014

FDA Approves First Insulin Automatic Injection Pen for Diabetic Dogs and Cats

VetPen, for use with Vetsulin (in USA) and Caninsulin (outside USA)
The U.S. Food and Drug Administration (FDA) has approved the first insulin injection pen (VetPen, Merck Animal Health) for diabetic cats and dogs, the agency announced today, March 19, 2014 (1).

2 Sizes of VetPens
The VetPen may now be used to administer Vetsulin insulin cartridges, also made by Merck Animal Health. The refillable VetPen automatically measures the prescribed insulin dose and provides the owners of diabetic dogs and cats with an additional option for insulin delivery.

There are two sizes of refillable VetPens. One (tan cap) dispenses insulin doses from 1-16 units per dose in full unit increments. The other (blue cap) dispenses 0.5-8 unit doses in full or half unit increments. Both pens use 2.7 ml insulin cartridges which hold a total of 108 units (IU) of U-40 Vetsulin (or Caninsulin).

Vetsulin is an FDA-approved insulin for use in dogs and cats (2). This insulin is identical to Caninsulin, the brand name of the insulin sold in Europe (3).

Merck said the VetPen is easier to dose and administer and is more accurate than traditional delivery systems, such as syringes and vials (4). “For years, insulin pens have made managing diabetes more convenient for human diabetics,” the company said. “Merck Animal Health has now brought the same technology to veterinary medicine.”

An informational website (2) provides tools for both veterinarians and pet owners to make managing pet diabetes easier. More online information about the VetPen can also be found on the Caninsulin website (5); the Pet Diabetes website has an informational brochure that can be downloaded (6).

Administering insulin to a cat with the VetPen
For questions on how to obtain Vetsulin or the VetPen, please contact Merck Animal Health Customer Service at 800-521-5767.


  1. FDA website. FDA Approves First Insulin Product for Use with Automatic Injection Pen in Cats and Dogs.
  2. Merck Vetsulin website. www.vetsulin.com
  3. Merck Caninsulin website. www.caninsulin.com
  4. Press release. Merck Animal Health Receives FDA Approval of VetPen  
  5. Merck Caninsulin website. Caninsulin® VetPen® helps make pet diabetes management easier 
  6. Pet Diabetes website. What you need to know about the Caninsulin VetPen

Wednesday, March 12, 2014

What's the Best Insulin for Treating Dogs with Diabetes Mellitus?

I am writing you regarding my 11-year old male Weimaraner, Duke. He has always been in good health but over this past week he has had 2 ”accidents” where he has urinated in the bed. He has also been drinking a lot more water than usual and urinating more too.

I  took him to the vet because I had a feeling he might be diabetic. My veterinarian confirmed that it was indeed diabetes mellitus and started him on 10 units of NPH, once after breakfast and once after dinner.  He has improved since starting the insulin, but remains quite thirsty and continues to urinate excessively.

Now I know that this will not give very good control alone because NPH is only a long-acting insulin. I am a Type 1 diabetic, diagnosed when I was 12 years old, so I have quite a bit of experience dealing with this disease. I want my poor puppy to be as controlled as possible so he does not feel like I do when my sugars are out of control— lethargic, nausea, headaches, unquenchable thirst, urinating all the time, and just plain crappy! Not to mention the stress this puts on the on the rest of the body.

If dogs are anything like people, I believe that Duke needs an insulin mixture that will bring his blood glucose down to normal and keep it leveled out. I have been giving him the rapid-acting insulin analog Humalog (insulin lispro) along with the NPH and that seems to be working really well, with marked improvement in his thirst and urination.  The only problem is that he needs 4-6 injections of Humalog each day. I was hoping you have had experience with something that would give him the same control as Humalog but with less injections daily.

In the past, I have used short-acting Regular insulin (before Humalog was invented) but I do not remember how the dosing went. I do have much better control with the Humalog but I am also on an insulin pump, so NPH insulin is no longer necessary.

Any help you can give to allow my dog Duke better control long term without so many injections would be greatly appreciated.

My Response:

In dogs, veterinarians commonly start with an intermediate-acting insulin (NPH or Vetsulin) twice a day (1,2). In some dogs, I find it necessary to add a short-acting insulin to the longer-acting insulin preparation, but many dogs can achieve adequate glucose control without giving more than 2 injections per day.

Insulin of choice for canine diabetics
In my opinion, the insulin of choice for most dogs is Vetsulin (porcine insulin zinc suspension; Merck Animal Health) (3). The main advantage of Vetsulin (known as Caninsulin outside the USA (4), is that it is actually composed of both short- and long-acting insulin components (see Figure below, showing the duel peaks of activity) (5,6). So giving Vetsulin is like administrating NPH together with a second, short-acting insulin preparation, like you are doing now.  However, Vetsulin works better than NPH for most dogs because it has a longer duration of action than NPH.

Timing of meals and insulin injection
The short-acting amorphous fraction of the Vetsulin, which composes 35% of the insulin activity, acts like regular insulin or Humulog, mainly to control the rise in blood glucose after each meal (6).  To help prevent severe rises in glucose after meals, however, it is also important to give the insulin before meals, instead of after the food is ingested, as you are doing now. This protocol will allow the short-acting insulin to be absorbed into the blood stream and ready to act to lower the blood sugar as soon as the food is absorbed from the gastrointestinal tract (7).

The only time I don't do this insulin-feeding protocol is in dogs that don't always eat their meal well; but even in those dogs, I never wait long after the meal is finished to give the insulin. Instead, I always give the insulin injection as soon as possible, once the dog has eaten a sufficient amount of food.

Vetsulin (porcine insulin zinc suspension), with it's 2 peaks of insulin activity


  1. Nelson RW. Canine diabetes mellitus In: Ettinger SJ, Feldman EC, eds. Textbook of Veterinary Internal Medicine: Diseases of the Dog and Cat. Seventh Edition ed. St. Louis: Saunders Elsevier, 2010;1449-1474.
  2. Davison LJ. Canine diabetes mellitus In: Mooney CT, Peterson ME, eds. BSAVA Manual of Canine and Feline Endocrinology. Fourth ed. Quedgeley, Gloucester: British Small Animal Veterinary Association, 2012;116-132.
  3. Vetsulin website. www.vetsulin.com 
  4. Caninsulin website. www.caninsulin.com
  5. Monroe WE, Laxton D, Fallin EA, et al. Efficacy and safety of a purified porcine insulin zinc suspension for managing diabetes mellitus in dogs. J Vet Intern Med 2005;19:675-682.
  6. Fleeman LM, Rand JS, Morton JM. Pharmacokinetics and pharmacodynamics of porcine insulin zinc suspension in eight diabetic dogs. Vet Rec 2009;164:232-237.
  7. Cobry E, McFann K, Messer L, et al. Timing of meal insulin boluses to achieve optimal postprandial glycemic control in patients with type 1 diabetes. Diabetes Technol Ther 2010;12:173-177. 

Friday, February 21, 2014

U-40 Insulin Syringes Recalled

Med-Vet International Issues Recall of 1/2-cc U-40 Insulin Syringes Due to Mismarked Syringe Barrels (1).  

On February 14, 2014 , Med-Vet International initiated a voluntary nationwide recall of 140 boxes of 1/2-cc U-40 insulin syringes (1). The syringes are incorrectly labeled as 40 units per 1/2-cc syringe, whereas they should be marked with only 20 units per 1/2 cc. Obviously, this could potentially result in a lower-than-prescribed dose of insulin being administered, and lead to relapse of signs of diabetes, as well as development of ketoacidosis.

Consumers who have these insulin syringes should quarantine all products subject to recall. In addition, if you, as the veterinarian, may have sold these syringes, please inform the clients at once about this product recall so they can change to another insulin syringe.

The following 1/2-cc U-40 insulin syringes have been recalled:
  • 140 boxes of 1/2-cc insulin syringe U-40 with 29g x 1/2” needle. Lot Number: 20120610
  • The product can be identified by Item number: MV1/2CCINS-40 or 1/2CCINS-40 by Oasis.
Med-Vet International is arranging for return of all recalled 1/2-cc U-40 insulin syringes. Consumers with questions may contact the company via telephone at (800) 544-7521 or via e-mail at customerservice@shopmedvet.com.

  1. FDA website (www.fda.gov). Med-Vet International Issues Nationwide Recall of Veterinary 1/2cc U-40 Insulin Syringes Due to Mismarked Syringe Barrels