Prescription Diets for Pets: Why are they necessary?
What is a "Prescription Diet" for Pets?
A "prescription diet" for pets is one that can only be sold by veterinarians. They are an anomaly because, typically, only drugs can be claimed as prescription products. The FDA is able to get around this by issuing extensive testing and requiring that only veterinarians be able to distribute the food product. However, the testing process is not as in-depth as is for drugs. Prescription diets are often called "therapeutic diets" because Hills has trademarked the term "prescription diet."
Why are Therapeutic Diets for Pets Necessary?
Therapeutic diets have nutrient levels that are appropriate for treating certain diseases but could be unsafe for healthy pets.
A great example of a therapeutic diet with unique nutrient levels is one designed for a dog with kidney (renal) disease. Renal support therapeutic diets have less protein than what's normally recommended for healthy dogs. They also have less phosphorus because the kidneys are not excreting phosphorus like they did when they were fully functional. It is up to the veterinarian to weigh the typical recommended nutrient sacrifices against the disease treatment.
The prescription status keeps the diet out of the hands of people whose dogs don't have the pertinent illness. Feeding the wrong therapeutic diet to a pet can be harmful. Therapeutic diets alone don’t cure a health problem, so a veterinarian must be monitoring the process in order for the pet to be treated properly. In the example of the urinary diet, crystals or stones can block the flow of urine and cause life-threatening disease, even if the appropriate urinary diet is being fed. A veterinarian would need to monitor the entire process - such as by periodically checking a pet for a urinary obstruction if they are straining to urinate or urinating smaller amounts. Another example is the need for monitoring blood tests to assess kidney toxin values, that may still be rising, even if the pet is exclusively fed the low protein, low phosphorus diet.
Why can Therapeutic Diets be so Expensive?
Why are therapeutic diets so expensive? You might be concerned that it is some kind of money-making scheme because you're dependent on the diet to keep your pet healthy and safe. But rest assured that is not the case. The simple answer? Testing. For example, ongoing testing of kidney diets are conducted by feeding the food to animals for many months. In the case of urinary diets, urine is tested for pH and the presence of crystals and the dietary management is evaluated for success, based on the results. Testing costs hundreds of thousands of dollars to implement.
What Conditions are Most Commonly Treated with Therapeutic Diets?
I prescribe prescription diets each day in my veterinary practice. They are usually not used alone to treat diseases, but are frequently used to augment other traditional therapies. The most common disorders that are responsive to dietary management are:
Urinary tract infections, specifically when urinary crystals or stones are present.
Kidney disease, low protein and phosphorous.
Digestive disease, especially for pancreatitis and inflammatory bowel problems. High fiber and easily digestible, low fat.
Behavioral problems in cats, such as intercat aggression. These diets contain natural calming ingredients (tryptophan and casein).
Heart disease in dogs, low sodium diets.
Osteoarthritis or degenerative joint disease, containing joint support ingredients, glucosamine and chondroitin.
Food allergies, dietary management is essential to treat both digestive and skin manifestations. Limited protein to one source or hydrolyzed processing that cannot trigger an allergy.
Diabetes, high fiber or low glycemic index. Can reduce the amount of insulin needed.
Obesity, high fiber, low calorie, satiety diets that make a pet feel more full.
What are the Most Common “Prescription Diet” Brands?
The most commonly used veterinary prescription diets are manufactured by Hills and Royal Canin. In my experience, Royal Canin diets are generally more palatable and therefore, more readily accepted, especially by cats. Royal Canin also has “multi-function” diets for cats. Examples are urinary combined with hydrolyzed, urinary combined with calm, renal with hydrolyzed, urinary with hydrolyzed and satiety with hydrolyzed.
I do use both companies when attempting to find a diet that a pet will accept and enjoy.
An annual examination is required in order to refill prescription diets, whether they are purchased from a veterinary clinic or online.