Prescription Pet Diets 101

Prescription Pet Diets 101

We've all been there: a routine visit to the vet takes an unexpected turn when a prescription diet is recommended for our dog or cat. Suddenly, terms like 'renal support' or 'urinary care' come into the conversation.

While it might be surprising, this recommendation highlights the crucial role of nutrition in pet health. Let's dive into why our vets sometimes steer us towards these specialized foods.

Table of Contents:

Prescription (or Rx) Pet Food FAQs

Common Rx Formulas

Understanding Your Pet's Needs

Kidney Disease

GI Distress

Skin & Allergy



Weight Management

Consult Your Vet

Final Considerations

Prescription (or Rx) Pet Food FAQs

What makes a prescription pet food different from a regular pet food?

Prescription pet foods are formulated to address specific dietary needs or restrictions associated with certain medical conditions. They do not contain medications or controlled substances in the same way that prescription drugs do. Instead, their formulations are adjusted in terms of nutrient content or ingredient selection to benefit a specific health condition or to avoid exacerbating it. 

What are the most commonly prescribed Rx pet food formulas?

And, what issues do they treat and how? Here are nine of the most commonly prescribed formulas, the issues they treat, and their mechanisms of action:

1. Kidney Disease Formulas:

    Issues Treated: Chronic kidney disease, renal insufficiency.

    How They Work: These formulas typically contain reduced protein levels, lower phosphorus levels, and controlled sodium to alleviate the workload on the kidneys. Some may also include increased omega-3 fatty acids to help reduce inflammation associated with kidney disease.

    2. Gastrointestinal (GI) and/or Food Intolerance Formulas:

    Issues Treated: Gastrointestinal upsets, food intolerances, inflammatory bowel disease, pancreatitis, malabsorption, diarrhea, and vomiting.

    How They Work: GI diets often contain easily digestible ingredients like hydrolyzed proteins and have moderate to low fat and protein levels. They may also include prebiotics and probiotics to promote a healthy gut microbiome. 

    3. Skin Allergies or Allergic Dermatitis formulas:

    Issues Treated: Itching and other skin irritations caused by environmental factors (examples: pollen, dust mites, flea bites) and, in rare instances, food allergies.

    How They Work: Theoretically, these diets work by enhancing the skin’s barrier against environmental irritants. Some diets also contain single-source proteins or novel proteins to account for the possibility of an underlying food sensitivity.

    See Dr. Laurie’s special note on allergic dermatitis!

    4. Urinary Health Formulas: 

    Issues Treated: Struvite and calcium oxalate crystals/stones, lower urinary tract diseases. 

    How They Work: These diets control mineral levels (like magnesium, phosphorus, and calcium) and modify urine pH. They also promote increased water intake to dilute the urine. 

    5. Weight Management Formulas: 

      Issues Treated: Obesity and diabetes. 

      How They Work: These diets are lower in calories but designed to be satiating. They might be high in fiber to promote a feeling of fullness or may have higher protein levels to support lean muscle mass during weight loss. 

      6. Joint/Mobility Support Formulas: 

        Issues Treated: Arthritis, joint pain, or other mobility issues.

        How They Work: These diets typically contain higher levels of omega-3 fatty acids (like from fish oil) which have anti-inflammatory properties. Some might also contain glucosamine and chondroitin sulfate for joint health. 

        7. Diabetic Formulas:

          Issues Treated: Diabetes mellitus.

          How They Work: These formulas may be higher in protein or may focus on consistent carbohydrate levels and may have increased fiber to help regulate post-meal blood sugar spikes. 

          8. Liver Disease Formulas: 

            Issues Treated: Liver conditions or liver insufficiency. 

            How They Work: These diets often have restricted copper levels, and provide antioxidants and highly digestible protein sources to support liver function without overburdening it.

            9. Dental Health Formulas: 

            Issues Treated: Plaque, tartar, and gingivitis. 

            How They Work: These diets are typically designed with a specific kibble shape and texture to provide mechanical cleaning of the teeth. They may also have ingredients that can help reduce tartar formation.

            Why can’t I purchase a prescription pet food from my local pet store?

            Manufacturers of prescription pet foods like Purina, Royal Canin, and Hill's Science Diet choose to sell their prescription diets only through veterinarians.

            This is, in part, to avoid misuse. Prescription diets are formulated for specific health concerns. Feeding a pet a prescription diet without a proper diagnosis can be harmful. For instance, a food designed for a dog with kidney disease might have reduced protein levels, which would not be suitable for a healthy, active dog.

            How can I address my pet’s health issue and still feed a more nature-based diet?

            We often hear the concern that prescription pet food is expensive and is made up of hyper-processed ingredients like meat by-product meal and corn gluten meal.

            So, we teamed up with Dr. Laurie Johnson for a vet’s-eye-view of health issues that commonly result in food prescriptions and how one can approach these challenges with fresh food options.

            About Dr. Laurie Johnson

            Dr. Laurie Johnson is an integrative veterinarian practicing in Austin, Texas (AcuDog HerbalCat Vet). She is certified in Acupuncture, Food Therapy, and Tui Na from the Chi Institute, and Integrative and Chinese Herbal Medicine through the College of Integrative Veterinary Therapies.

            She is a doctor of veterinary medicine (DVM) with over 15 years of experience in the field. Dr. Laurie Johnson has a diverse medical background in wildlife, emergency, shelter, small animal medicine, and surgery and is licensed in Food Therapy (CVFT) via the Chi Institute.

            Understand Your Pet’s Needs & Find a Food to Suit Them

            Now that we’ve covered Prescription Diets, let’s nail down a food or supplement to fit your pet’s needs. Below are some criteria by which you should evaluate foods according to your pet’s health issue, paired with real cases from Dr. Laurie Johnson’s practice.  

            Kidney Disease Diets:

              🔍 Find a pet food with:

              • Lower levels of protein, phosphorus, and sodium.
              • Gently-cooked lean meats (in moderate amounts)
              • High-quality protein sources
              • Green beans, carrots, and other low-phosphorus vegetables.
              • Supplement with omega-3 fatty acids from fish oil for anti-inflammatory benefits.

              👍 Some options to run by your vet:

              SquarePet’s VHS Low Phosphorous Dry Dog Food checks many of these boxes for dogs with later stage kidney disease

              Weruva WX formulas are specially formulated for supplemental feeding for cats in later stages of kidney disease when phosphorus levels are elevated. 

              🩺 Dr. Johnson’s Cases:

               A 14 year old male cat, who began his life as a feral kitten. He's always been a hunter, so his natural constitution is one of an instinctive carnivore. 

              He has stage 1 kidney disease. He always thrived on a commercially available raw food diet. His parents tried feeding him a canned prescription kidney diet. He lost his appetite, lost weight, and muscle mass. We changed his diet to Instinct Raw Longevity and he loves it. He's also on herbals and supplements to support kidney health and has regular blood work to monitor his kidneys.

              A canine patient with stage 3 CKD stopped eating the prescription low phosphorus kidney diet and only wanted to eat meat and treats, so his diet was very unbalanced. We supplemented his diet with gently cooked A Pup Above Pork or Chicken on a rotational basis. He was a large dog so this was added to his base prescription kibble diet at a ratio of ~30-40% fresh food to ~60-70% prescription kibble. He ate more consistently, took his herbs and supplements better and was closely monitored. 

              GI Distress or Food Intolerances:

              🔍 Find a pet food with:

              • Hydrolyzed protein or limited ingredient diets with a single protein source. 
              • Novel, single protein sources that the pet hasn't been exposed to. 
              • Fresh, whole foods with minimal processing to reduce the chance of reactions to additives.
              • Pursue a food elimination strategy: try only one new food at a time and eliminate any formulas that don’t agree with your pet.  

              👍 Some options to run by your vet:

              Zignature’s Kangaroo and RAWZ Limited Duck are well-loved formulas for dogs.

              RAWZ 96% Rabbit and 96% Duck are popular options for cats.

              🩺 Dr. Johnson’s Cases:

               A 4 year old feline with a history of chronic intermittent diarrhea since a kitten did great on Stella and Chewy's Freeze-Dried Raw and a course of herbals and supplements to rebalance gut health. We initially tried other raw and canned diets, and she ultimately preferred the texture of the reconstituted freeze-dried raw.

              A 12 year old terrier mix with IBD didn't tolerate a home cooked prescription diet formulated by a boarded veterinary nutritionist. We changed her diet to Square Pet VFS Digestive Support Low Fat Kibble and started some herbals and supplements to help her gut heal. Because she didn't require a severely fat restricted diet long term, we slowly transitioned her to Open Farm Gently Cooked Turkey.

              Skin or Environmental Allergies (Allergic Dermatitis)

              Dr. Johnson Note: "In my practice, Itchy skin (allergic dermatitis) responds best when the diet is the most appropriate for the individual pet: Some pets have dry skin, some have greasy skin, some have a combination of both.

              Some of these conditions are hot and inflamed (skin infections, ear infections) and some are cold (hair loss, other complicating factors like hypothyroidism or another metabolic or endocrine disease).

              Does the pet have seasonal allergies to the environment (atopic dermatitis)? Year-round symptoms suggest allergies to antigens in the household (ex: dust mites, storage mites, mold, fleas, food).

              As you can see, allergic skin cases are not simple, and many of these poor pets have chronic conditions. They can get better, but it does take time and patience as we work through the process of identifying the allergies, focusing on healing the damaged skin while taking a closer look at digestion and gastrointestinal health as many pets have been treated with multiple rounds of antibiotics. My more severe skin cases respond best to an integrative approach, especially in the beginning."

              🔍 Find a pet food that:

              • Dr. Johnson tends to make recommendations based on the individual pet and their constitution.
              • Proteins considered “cooling” in Eastern traditional medicine, like duck or fish, may help reduce inflammation triggered by environmental allergies.
              • Omega-3s like those found in fish oil are shown to help reduce inflammation by helping to decrease the production of inflammatory eicosanoids and cytokines. 

              👍 Some options to run by your vet:

              Small Batch makes a stellar Duck formula for both dogs and cats in frozen and freeze-dried forms. Nulo’s Limited+ Salmon formula also ticks many boxes.

              Supplementing with Fish Oil is a no-brainer, and Nordic Naturals is among the best.

              🩺 Dr. Johnson’s Cases:

               I’ve had many cases in which feline patients with diagnosed skin allergies improve significantly with the introduction of an instinctive carnivore diet appropriate for their constitution. This can be challenging as some cats are addicted to carbs! If you have a picky cat and struggle with food transitions, Lisa Pierson DVM’s tips are a great resource!

               A 6 year old dog had chronic allergies manifesting in the skin. This dog was very hot and itchy so we chose a raw food diet with cold energetics and novel protein. Our top choices were Primal Raw Duck or Rabbit. We added herbals, supplements, and topical therapies. This regimen combined with personalized food therapy helped her skin heal over time and greatly reduced her allergic response.

              Diabetic Diets:

              🔍 Find a pet food with:

              Fresh or frozen formulas with high fiber and complex carbohydrates. In some cases, high protein, low carbohydrate diets are a better choice. Look for ingredients like:

              • Fresh vegetables that are high in fiber.
              • Whole grains
              • Lean meats
              • And, monitor blood sugar levels closely with your veterinarian when making dietary changes.

              👍 Some options to run by your vet:

              Frozen or freeze-dried raw can be excellent options for these diets.

              Bones & Co’s keto-friendly formulas are rich in blood sugar-balancing fiber sources like broccoli and flaxseed (plus, meat and organ meats).

              Dr. Johnson Note: "Many raw food brands have resources specifically for vets who may be reluctant to recommend raw. This one from Instinct Pet Foods is a great one; check if your preferred brand has their own vet-facing resources with breakdowns on their safety practices, pathogen testing, and more."

              🩺 Dr. Johnson’s Cases:

              I often see feline patients with Type 2 diabetes, which can go into remission with nutritional therapy. Felines are obligate carnivores but can easily become addicted to heavy carbohydrate kibble diets. This often causes significant weight gain and Type 2 diabetes. Going back to their instinctive diet is key to curing diabetes in most cats.

              Dr. Johnson Note: "Some cats may have other medical conditions that can make them harder to regulate so it's important to address any other complicating health issues. My feline patients with more advanced disease need insulin therapy while they are getting in shape on an appropriate diet."

              My canine diabetic patients are most often Type 1, which means they are insulin dependent. Even though we can't cure their diabetes, we can get them much healthier and balanced on an appropriate diet for their individual constitution. Most diabetic dogs do well on a fresh, whole food, balanced diet that is anti-inflammatory in nature.

              Urinary Health Diets:

              🔍 Find a pet food that:

              • Increases water consumption, contains controlled mineral levels, and supports urinary tract health by regulating urine pH.
              • Wet food or moisture-rich diets to promote hydration. 
              • Commercially available foods that contain cranberries or blueberries (in moderation) can promote urinary health. 
              • Routine urinalysis (including urine pH monitoring) is often recommended by your veterinarian. 

              👍 Some options to run by your vet:

              Primal’s Freeze-Dried Dog Food and Cat Food can be rehydrated with lots of water for moisture, contains cranberries and blueberries, and is free of spinach, beets, and sweet potatoes (for those who are prone to oxalate crystals)

              Farmina makes urinary health-friendly formulas for cats in both canned and dry options.

              🩺 Dr. Johnson’s Cases:

               Many of my feline patients with mild urinary challenges do well on wet food diets. Others may need urinary friendly diets. Most of these cats should be able to transition to fresh, whole food diets with high moisture content.

              Cats with more significant urinary conditions requiring emergency visits to the vet may need to stay on prescription urinary diets longer term.

              Dr. Johnson Note: "In cats, urinary challenges can result from stress. Stressed kitties often don't drink enough water, causing their urine to become very concentrated. Crystals can form in concentrated urine and the bladder can become severely inflamed leading to life threatening conditions. It's important to identify and address the underlying cause of stress while also making sure your kitty stays well hydrated on a high quality wet food diet."

              Reduce their stress with these Team Favorite calming treats and enrichment toys for cats.

               A canine patient was diagnosed with a surgical case of bladder stones. A genetic predisposition was suspected. He was on a prescription urinary diet for about 8 months before and after surgery. Once stable, we transitioned him to a home cooked urinary diet we designed using His pet parent made sure he drank lots of water and had routine screening tests to check for crystals and stones. She monitored his urine pH at home. 

              Weight Management Diets:

              🔍 Find a pet food with:

              • Low calories but satiating levels of protein and fiber. 
              • Lean proteins like chicken breast or fish. 
              • Fresh vegetables to add volume without many calories. 
              • Regular exercise in combination with a controlled diet. 

              👍 Some options to run by your vet:

              Fresh food diets are excellent for weight management: they are palatable, satiating, and healthy.  Some pets who are unable to lose weight on kibble diets, even prescription diets, may lose weight on a complete and balanced whole food diet. A Pup Above and Open Farm’s gently cooked formulas are great for weight management in dogs. 

              Savage Cat’s raw food formulas have all the meat and organ meats  to satisfy your tiny lion. It also contains psyllium husk as a prebiotic and natural fiber source. 

              If commercially available frozen raw food diets (dog foods or cat foods) are suitable for your pet and your budget, they can be an excellent option for those struggling to lose weight.. 

              🩺 Dr. Johnson’s Cases:

               : For both my canine and feline patients dealing with weight issues, I most frequently recommend a 100% whole food diet for 2-3 months as a therapeutic trial. This could include commercially available frozen raw or gently cooked balanced diets.

              Dr. Johnson Note: "It may cost more up front than the prescription diet, but the health benefits could go far beyond weight loss. Food is medicine!"

              Consult with Your Vet

              Once you’ve found a food that you think may meet your pet’s health needs, run it by your vet first.  

              Be upfront with your vet about your wishes and concerns. Your vet’s first priority is to keep your pet healthy and safe; they will know what are the critical qualities that your pet needs in a food and considerations to keep in mind. 

              And, there are a lot of pet foods out there on the market! It may be that your vet doesn't know about some of the high quality diets that are commercially available, and because of this, their default may be to recommend prescription diets they are familiar with. 

              Or, if your vet dismisses your concerns and insists that a prescription diet is the only path forward, seek a second opinion from another vet.  

              For certain, more emergent medical conditions like feline idiopathic cystitis, urinary crystals or stones, prescription diets may be medically necessary until the patient has completely recovered. For other conditions like obesity or food sensitivities, there may be viable non-prescription options. 

              Final Considerations 

              Consultation: Before making any dietary changes, especially for pets with health conditions, always consult with your veterinarian.

              Transition Slowly: When introducing new foods, do so gradually over a week or more to avoid gastrointestinal upset. This advice even applies to elimination diets in which you’re trying to rule out offending ingredients. 

              Quality Matters: Opt for high-quality, human-grade ingredients. Avoid foods with fillers, additives, or artificial preservatives. 

              Monitor and Adjust: Regularly monitor your pet's health, weight, and overall condition. Adjust the diet as necessary, keeping an open line of communication with your veterinarian. 

              Nature-based pet food alternatives can offer a fresh, natural approach to pet nutrition. However, they require careful planning, especially when used to manage health conditions. The goal is to ensure that your pet receives balanced, nutritious meals that support overall health and specific health challenges. Always prioritize your pet's well-being, seeking expert guidance as needed.

              Looking for more Pet Parenting tips?

              Tomlinson's is your go-to pet supply store for natural, healthy pet products in Austin and the Central Texas region. Let us help prepare you and your home for your pet(s). 

              Visit our shop full of products sold through team members trained in animal nutrition. Pass by our stores with your adorable pet for some treat samples and loving ear rubs.

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