Recent guidance on therapeutic pet diets published by the U.S. Food and Drug Administration Center for Veterinary Medicine (FDA-CVM) has raised so many questions among veterinarians, the agency scrubbed the content from its website.

"In our attempt to clarify our regulatory authority with regards to therapeutic diets, we unfortunately (and unnecessarily) caused confusion ...," acknowledged Laura Alvey, FDA-CVM spokeswoman, in an e-mail to the VIN News Service. "We are looking at ways to provide clearer information."

CVM Director Dr. Bernadette Dunham addressed the serious nature of therapeutic diets in the Dec. 15 issue of the Federal Veterinarian, noting in a Q&A session that foods branded as "prescription" or "therapeutic" truly need to come out of a veterinarian's office, released by prescription. She stated, in part: “Requiring a valid prescription and restricting the sale of the food through a licensed veterinarian are safeguards against unintended harmful effects. Because the manufacturer requires a prescription, the food cannot be sold or marketed like the pet food you see in stores.” (See image)

That statement struck many veterinarians as contrary to their belief that the agency's regulatory purview did not extend beyond legend drugs to include pet foods. It also raised questions concerning whether veterinarians should continue to apply sales tax to therapeutic diets in states that exempt prescription medications — a topic that incited discussion on the Veterinary Information Network (VIN), an online community for the profession.

Dunham's references to pet foods in the Dec. 15 Q&A were truncated late last week, but not before riling veterinarians who had long believed that manufacturers — not regulators — called for practitioners to write prescriptions for diets branded as "prescription" or "therapeutic." Examples in this dietary class include lines of Hill's products as well as certain foods manufactured by Iams, Royal Canin and Purina. Consumers purchase therapeutic diets in veterinary offices rather than in stores, per a veterinarian's directive.
 
(Hill's, one of the nation's largest manufacturers of pet foods, has trademarked the term "prescription diet." Because of the trademark protection, competing manufacturers use the term "therapeutic" to describe foods that perform similar levels of nutritional function.) 

Many veterinarians do not treat therapeutic diets as seriously as drugs, believing that tagging a pet food as "prescription" or "therapeutic" merely is a way for manufacturers to elevate the status of certain diets under the shroud of medicinal purposes. Dr. Wesley Borgman, a VIN member and practitioner near Orlando, said that it's common practice in his area to sell therapeutic diets to vacationing owners without a prescription or examination.

"The FDA doesn't regulate nutraceuticals. These diets are just one big nutraceutical," he reasoned.

For the most part, therapeutic diets are "just a stone's throw" away from traditional, over-the-counter pet foods, added Canadian practitioner Dr. Joe Walman, another VIN member.

Hill’s Pet Nutrition, Inc., manufactures two lines of foods designed to help control weight in companion animals — one is labeled a prescription diet while the other  is not. Amy Thompson, a company communications specialist, explained the differences between the two products this way:
 
“The distinction in our foods is either in the restriction or increase in certain nutrients that can have an effect on metabolic processes. For example, Prescription Diet r/d is our lowest calorie product. Due to the calorie restrictions, it is not recommended for long-term feeding."
 
By contrast, Science Diet Light, sold in stores, "has been shown through … feeding tests to be 'complete and balanced' and suitable for long-term feeding without veterinary supervision,” Thompson wrote in an e-mail to the VIN News Service.

But the issue extends beyond caloric thresholds, according to Dr. William J. Burkholder of the FDA-CVM’s Division of Animal Feeds, who authored a 2003 report on the therapeutic diets, published in the Journal of the American Veterinary Medical Association (JAVMA).

Heavy with bureaucratic language, the article characterized such foods as "illegal" products because they have not been proven safe and effective for their intended uses. Burkholder noted that the FDA through “its enforcement discretion” allows therapeutic diets to be regulated as food even though they should be considered drugs because of their intended effect.

Translation: What manufacturers are doing in terms of branding is illegal, but regulators are willing to look the other way if the diets are made available only through licensed veterinarians, provided that there is a valid veterinary-client-patient relationship.

CVM spokeswoman Alvey confirmed with the VIN News Service that the agency's current position on therapeutic diets mirrors what Burkholder expressed in his 2003 article. She added that Dunham's characterization of therapeutic diets in the Federal Veterinarian was not meant to reflect a new regulatory stance.

"The word, 'prescription' was used to convey that a veterinarian needs to be involved in order to assure these products are used correctly and safely. FDA has always viewed these products as drugs and a 'prescription' is a way to demonstrate veterinarian involvement," she said. 

In light of the notion that federal regulators — not just manufacturers — are behind the sales and prescription stipulations for therapeutic diets, veterinarians are concerned about how such products should be handled. They also want the bottom line on whether therapeutic diets should be excused from sales tax.

“If FDA is now saying it’s a prescription, then clients should not be charged sales tax when they purchase prescription diets for their pets,” said Borgman, the practitioner in Florida, a state that exempts medications from sales tax.
 
But Douglas Kemp, a PharmD and VIN consultant, shuns the notion that therapeutic diets should be treated as drugs via taxation, handling and otherwise, because the ingredients in such high-end formulations do not contain drugs regulated by the FDA.
 
"The diets do not contain prescription-label drugs. It is a marketing ploy," he said.
 
Officials in states that exempt prescription medications from sales tax assessments seem to agree with Kemp's line of thinking. So far, efforts to extend tax exemptions to therapeutic pet foods have been rebuffed by various state legislatures and agencies. Simply put: pet foods are not drugs, despite the therapeutic designation.
 
The Florida Department of Revenue, for example, clamped down on any notion that therapeutic diets should be free of sales tax. Last July, new language added to the Florida Administrative Code went into effect, stipulating that veterinarians and their clients can only avoid sales taxes on products carrying the following label:
 
“Caution: Federal law restricts this drug to sale by or on the order of a licensed veterinarian."
 
The new rule clears up any notion that therapeutic pet foods might not be subject to sales tax by noting that to be exempt, pet foods must also "be required by federal or state law to be sold by prescription," stated Renee Watters, spokeswoman for the Florida Department of Revenue.
 
In response to the rule, the Florida Veterinary Medical Association (FVMA) is drafting legislation calling for a sales tax exemption on therapeutic diets. As it stands, no pet diet warrants the cautionary label as defined in the state's regulatory language.
 
"They do not have that label, and we have to charge sales tax," said FVMA District Representative Dr. Jerry L. Rayburn in an interview with VIN News Service.
 
Some practitioners believe it is appropriate to require certain foods to be sold only under the supervision of a veterinarian. “The (Hills) r/d diet is an extremely restrictive diet and you can harm the animal,” said Dr. Robert T. Sullivan, practicing in Montrose, Pa.
 
That’s not a convincing argument for authorities in Pennsylvania, where state law requires veterinarians to collect sales tax when selling therapeutic diets. Medicines and medical supplies are exempt.
 
Lawmakers responsible for enacting the distinction believed that the primary function of therapeutic diets was nutritional, not medicinal, said Allison Roberts, a spokeswoman for the Pennsylvania Department of Revenue.
 
But no matter how state sales taxes are levied, the burden often is buried from public view.
 
New York law, for example, requires manufacturers to assess taxes from the sale of therapeutic pet foods to veterinary practices. The veterinarian may not explicitly re-levy the tax on his customers but may recoup the cost through the price of the food, said Susan Burns assistant director of public information with the New York State Department of Taxation and Finance.
 
California, with roughly 7,000 licensed veterinarians in the state, requires practitioners to pay a use tax on the wholesale cost of prescription drugs. For non-prescription products, pet foods included, the onus falls to veterinarians to collect and remit sales tax on retail sold to consumers, explained Dan L. Segna, assistant director of the California Veterinary Medical Association.