As a follow-up to the last two posts I've made on "prescription" foods, I wanted to add this topic. It's actually something that is currently being debated by the profession for various reasons and there is misinformation out there. In fact, astute readers may have noticed that I've frequently put the word prescription in quotation marks over the last week of posts. My discussion is going to focus on the US, even though I have an international readership, because I know US laws and not ones in other countries.
To begin, "by prescription" really does have a definition. Each state has their own laws so there are essentially around 50 different variations on the theme, but there are a lot of similarities. The basic idea is that there are certain medications that have been established by the Food and Drug Administration (FDA) as requiring a prescription from a licensed doctor. Without that prescription you cannot purchase the medication or product. States typically require a prescription to be written by a licensed doctor that has a valid client-patient-doctor relationship with that person or pet. The specifics may vary, but essentially the doctor must have personally seen the patient within at least the last 6-12 months and be familiar with their medical conditions and history. Over time some prescription-only medications can be approved for over-the-counter use, such as many antihistamines and stomach acid reducers. Whether or not a drug is by prescription is determined by the FDA, and what is required to issue a prescription is determined by the state.
What about "prescription" foods as produced by Hill's, Royal Canin, Eukanuba, and Purina? Here's a shocker for you....they technically do not fall under prescription laws.
Yes, that's right. These "prescription diets" do not legally require a prescription. They fall into a gray area of foods and supplements that the FDA does not regulate. It's similar to taking Echinacea for colds or St. Johns wort for depression. The manufacturers do not specifically claim that these products treat any specific condition, and they often even say so on the label. By not making a claim of treatment they can bypass the FDA regulations and do not have to prove their efficacy. Any claims come by word-of-mouth between people or through books and internet sites, but not directly from the product label.
So-called prescription foods in veterinary medicine occupy the same category as vitamins and supplements for humans. They do not go through any FDA trials or tests, and therefore do not fall under that agency's jurisdiction. Since it's the FDA that determines whether something is dispensed by prescription, these foods technically don't need one because the FDA hasn't ruled on it. And because they don't legally require a prescription, a valid client-patient-doctor isn't necessary.
So why do vets require a visit? Why do vets talk about these foods as "by prescription".
Some of these diets are fine no matter the health status of the pet that eats it. Others, however, could cause problems. For example, diets for kidney failure have significantly low protein levels. This is necessary to help progression of kidney disease, but it's low enough that we wouldn't want a health pet eating it. We don't want a client picking up a food for urinary issues because their dog is peeing a lot, when in reality that dog has diabetes and should be on a much different diet. Clients also aren't sure exactly which food they need or even have purchased in the past, so we don't want them to be able to just pick up any food and make their own judgment.
Using the wrong therapeutic diets can indeed lead to health consequences because of how highly specialized they are. By requiring authorization from a vet both the doctor and the food manufacturer take steps to ensure that the correct food is being given to the right patient and we're not doing any harm to pets. If someone wants to buy a therapeutic diet from my clinic we don't require that we have seen them, but we do require a written or oral confirmation from their vet as to which food is being used.
Recently the FDA has been paying more attention to these foods, since they actually are recommended and used for the treatment of diseases. Anything with that definition must be regulated by the government, and foods currently aren't. This is leading to discussions as to whether or not the FDA may actually start doing tests and requiring that foods follow the same laws and rules as antibiotics, antidepressants, and other medications. If so, expect the cost of food to go up because compliance on these issues is very expensive for the manufacturer.
This increased government scrutiny has already resulted in some changes by the food companies. For example, Royal Canin makes a diet for food allergies that breaks down the proteins into single amino acids, putting their size below the threshold that would trigger an allergy. It used to be named Hypoallergenic, but that name implies a specific claim about the function of the food in relation to a disease. Because that treatment claim would classify it as a medication and the Royal Canin wanted to avoid trouble with the FDA, they changed the name to Ultamino. Same product and no change in the ingredients, but an important change to comply with prescription laws and regulations. Several other foods have had name changes for similar reasons.
When your vet talks about a "prescription" food, realize that they are using the word loosely and probably incorrectly. Heck, I've been doing it for 30 years, so I still fall into that habit even though I know better. If you walk into a store or vet clinic and they don't know you, understand that they may not sell you the food, but not because of the law. In fact, if they say that it is illegal for them to sell it to you they are absolutely wrong since it doesn't fall under prescription drug laws. But there are darn good reasons for them not to sell it to you if they don't know the specifics of your pet's case.
Hopefully this makes sense, as it's a somewhat complex issue.