Introduction
Diabetes is a chronic disease that affects how the body processes glucose, or blood sugar. In dogs, the most common form of diabetes is diabetes mellitus, where the pancreas fails to produce enough insulin or the body becomes insulin resistant. According to epidemiological studies, the prevalence of diabetes in dogs has increased in recent years, with some estimates around 0.3-0.4% of the dog population affected (Yoon et al. 2020).
Managing diabetes in dogs typically involves daily insulin injections to regulate blood sugar. However, giving injections can be difficult for some owners. As a result, researchers have explored alternative insulin delivery methods, like oral insulin pills or tablets. Understanding the development and availability of oral insulin for diabetic dogs is an important topic for owners seeking easier treatment options.
Types of Diabetes in Dogs
There are two main types of diabetes that can affect dogs: diabetes insipidus and diabetes mellitus.
Diabetes insipidus is a rare disorder where a dog’s kidneys cannot properly concentrate urine, leading to excessive thirst and urination. It is caused by a lack of vasopressin, a hormone that regulates water reabsorption in the kidneys. Treatment involves replacing vasopressin or restricting water intake (1).
Diabetes mellitus, commonly known as sugar diabetes, is the more common form of diabetes in dogs. With this disease, the pancreas cannot properly produce or respond to insulin, the hormone that allows glucose to enter the cells. This causes high blood sugar and glucose spilling into the urine. There are two types of diabetes mellitus:
- Type 1 diabetes – the pancreas cannot produce enough insulin. This is the most common type in dogs. It requires lifelong insulin injections to manage blood sugar (2).
- Type 2 diabetes – the body becomes resistant to insulin. Oral medications used for human Type 2 diabetes do not work in dogs. Dogs with this type still require insulin injections (3).
How Insulin is Typically Administered
Most dogs with diabetes receive their insulin through injections under the skin (subcutaneous injections). This is considered the standard method of administering insulin to dogs. The injections are given 1-2 times per day, often right before a meal.
To give a dog an insulin injection, a small needle is used to pierce the dog’s skin and deposit the insulin solution into the subcutaneous tissue, the fatty layer between the skin and muscle. The ideal injection sites are areas where the dog has enough skin and fat to absorb the insulin, such as the neck, shoulders, or hindquarters.
The steps involved in giving a dog an insulin injection typically include:
- Washing hands and preparing supplies – insulin, syringes, alcohol swabs
- Gently lifting or parting the dog’s fur to expose the injection site
- Cleaning the injection site with an alcohol swab
- Drawing up the proper dose of insulin into the syringe
- Pinching up some skin/fat and quickly inserting the needle at a 45 degree angle
- Depressing the plunger to administer the insulin dose
- Holding for 5-10 seconds then withdrawing the needle
- Providing a treat and praise for the dog
- Properly disposing of used needles
Most dogs tolerate the injections well, but some may experience discomfort or irritation at the injection site. Gentleness, routine, and positive reinforcement can help make the process easier for the dog.
Challenges of Injectable Insulin
Injecting insulin can be challenging and stressful for both dogs and their owners. According to a study by Hulsebosch et al. (2022), owners often cite insulin-related issues as a major cause of anxiety. Specific concerns include worrying about hypoglycemic events and the inability to administer injections properly [1].
Insulin injections are painful and uncomfortable for dogs. The needles must be inserted under the skin and into the fat layers. For owners, reliably administering shots at consistent times daily can be difficult. Pet parents may also struggle with proper injection techniques like pinching up enough skin or injecting at the right angle [2]. Both factors can lead to poor regulation of blood glucose.
Overall, injectable insulin poses many challenges. The discomfort for dogs and difficulties for owners contribute significantly to poor compliance. More user-friendly alternatives would ease much of the anxiety surrounding insulin therapy for diabetic dogs.
Oral Insulin Research
Research into developing an oral form of insulin for dogs has been ongoing for several decades. Early studies in dogs in the 1990s showed promise in delivering insulin orally and observing changes in glucose metabolism consistent with insulin absorption from the gastrointestinal tract [1][2]. However, the bioavailability of oral insulin was very low, only 1-3% of the administered dose reached circulation.
More recent research has focused on improving the bioavailability of oral insulin using novel drug delivery methods. These include encapsulating insulin in nanoparticles to protect it from digestive enzymes, using permeation enhancers to increase gut absorption, and developing insulin analogues that are more stable. One 2020 study demonstrated an oral insulin formulation with 16% bioavailability in dogs [3]. While progress has been made, the development of a commercially available oral insulin with adequate efficacy for diabetic dogs remains elusive.
Ongoing research is focused on optimizing insulin stability, absorption, and activity profiles after oral administration. If these challenges can be overcome, an oral insulin product would provide a non-invasive and more convenient alternative to injections for diabetic dogs.
Benefits of Oral Insulin
An oral form of insulin for diabetic dogs could provide several advantages over injectable insulin. First, oral administration is often less stressful and painful for dogs compared to receiving injections. Many dogs dislike and resist getting insulin shots. An oral pill would eliminate the need for needles, potentially improving compliance and regulation of blood glucose levels.
Oral insulin may also allow for more consistent insulin absorption compared to injections. Research shows injectable insulin absorption can vary significantly based on factors like injection site, technique, and activity level after the shot. Pills pass through the digestive tract resulting in steadier insulin uptake. This could lead to better glucose control with fewer spikes and drops.
Additionally, oral insulin may require less intensive blood glucose monitoring. Owners currently need to track response to insulin injections multiple times daily. With standardized pill absorption, blood sugar testing may be needed less frequently. This would reduce costs and be more convenient for owners.
Finally, a pill could provide precise insulin dosing tailored to the dog’s needs. As injectable insulin comes in set concentrations, dosing adjustments require changing injection volume. Pills may enable more customizable doses while avoiding the need to handle needles.
Status of Oral Insulin Products
While injectable insulin has been available for dogs for many years, there are currently no oral insulin products approved for canine use. However, research into developing an effective oral insulin formulation for dogs is ongoing.
In December 2022, the FDA approved the first oral insulin product for diabetic cats called CoreAlpha. This medication, made by Elanco, contains a novel proprietary insulin molecule called protamine zinc insulin and comes in a beef-flavored chewable tablet. While a major breakthrough for feline diabetes management, CoreAlpha is only approved for use in cats at this time.1
Researchers face difficulties developing oral insulin for dogs due to the digestive process breaking down insulin before it can be absorbed. Dogs have a more acidic stomach pH than humans which degrades insulin. Scientists are exploring ways to protect insulin from digestion such as encapsulation methods.
Some veterinary compounding pharmacies offer non-FDA approved compounded oral insulin gels and suspensions for dogs. However, these products lack rigorous testing and their efficacy and safety are questionable. Pet owners should exercise caution using unregulated medications.
While no approved oral insulin products currently exist for diabetic dogs, researchers are actively pursuing this goal. Advancements for feline oral insulin provide hope that an effective canine formulation may be on the horizon.
Alternatives to Insulin Injections
Currently, the only FDA-approved alternatives to insulin injections for diabetic dogs are oral medications that help control blood glucose levels. The most commonly prescribed oral medications are:
- Bexagliflozin – This SGLT2 inhibitor was approved by the FDA in 2022 as the first oral anti-diabetic medication for dogs. It works by blocking glucose reabsorption in the kidneys, increasing glucose excretion. 1
- Glipizide – This medication stimulates the release of insulin from the pancreas and is sometimes used in combination with insulin injections. It comes in tablet form. 1
These oral medications may allow for less frequent insulin injections or lower insulin doses in some dogs. However, they do not completely replace the need for insulin therapy in most diabetic dogs. More research is still needed to develop additional oral alternatives to insulin injections.
Outlook for the Future
While oral insulin therapy would provide major benefits for diabetic dogs and their owners, an approved oral insulin product for veterinary use does not currently exist. However, research is ongoing to develop an effective oral insulin that can stabilize blood glucose levels in dogs.
One recent study published in 2021 demonstrated the ability to encapsulate insulin in a lipid-based oral formulation that enhanced the insulin’s stability and absorption in beagle dogs (https://pubmed.ncbi.nlm.nih.gov/33479345/). The researchers found this oral insulin preparation was able to significantly reduce blood glucose levels for over 8 hours. While additional research is still needed, this study provides hope that an effective oral insulin for diabetic dogs could become commercially available within the next several years.
Other novel delivery methods for insulin are also being explored, such as transdermal patches and nasal sprays. These alternative delivery routes could similarly eliminate the need for injections while providing steady insulin absorption. However, an oral preparation may be the simplest and most convenient approach for pet owners to manage their dog’s diabetes.
In summary, while a veterinary oral insulin is not yet commercially available, active research efforts make it likely we will see this type of product reach the market within the next 5-10 years. An oral insulin would greatly simplify therapy for diabetic dogs and their owners, making this an important area of innovation to monitor in veterinary medicine.
Conclusion
In summary, while injectable insulin is currently the standard treatment for diabetic dogs, researchers are exploring more convenient oral insulin options. Oral insulin could make treatment easier for dogs and owners, improve compliance, and provide better blood sugar regulation. However, producing a viable oral insulin product for dogs has proven difficult so far. While an oral canine insulin is not yet commercially available, there are alternative injection devices that can make giving insulin shots less stressful. Ultimately, the future holds promise for simplifying insulin delivery methods for diabetic dogs. With continued research, oral insulin or other non-injectable options may become a reality. For now, work closely with your veterinarian to find the optimal insulin regimen and delivery method for your diabetic dog. Consistent treatment and monitoring are key to managing this chronic condition and maintaining your dog’s quality of life.