On The Shelf
Mickie Cathers
For many people, our pets are important members of our family, and just as we care for our own health and well-being, we care just as much about supporting the health of our pets.
The pandemic increased pet ownership and allowed owners to be home all day with their furry family. The past few years have also seen an increased demand for organic and allergen-free pet food and treats as well as supplements to improve joint and digestive health, anxiety, cognition, skin and coat, and heart health in pets. Morgan Stanley Research posits that the U.S. pet industry revenue could nearly triple from over $100 billion to $275 billion by 2030.
Lack of sufficient evidence
Top sellers in supplements and vitamins for pets include probiotics to address gut health, itchy skin, and seasonal allergies. Products for dogs include hip and joint supplements containing glucosamine chondroitin, salmon oil with omega 3 for skin and coat as well as immune and heart health, adenosylmethionine and silybin for liver health, and cannabidiol for anxiety. Supplements specifically aimed at cats include remedies for hairball control, UTIs, and kidney disease.
There is a lack of information about potential drug and supplement interactions in vet pharmacy. Systematic reviews are uncommon in veterinary medicine and virtually nonexistent for pet supplements. Most claims of efficacy are based on owner testimonials, not clinical trials published in peer-reviewed journals.
Another cause for concern is that some ingredients that are safe for humans are not safe for animals. Excess garlic can cause hemolytic anemia in dogs, cats, and horses. NSAIDs combined with herbs that may have antiplatelet effects—including gingko, ginger, ginseng, and garlic—may increase bleeding risk. One study reported adverse reactions in 47 dogs, including death in 8, after ingestion of a weight loss supplement containing guarana (caffeine) and ma huang (ephedrine). A systematic review from 2012 found poor evidence of efficacy for all nutraceuticals meant to treat osteoarthritis in dogs except for omega-3 fatty acid.
No oversight
Despite widespread use and expanding popularity, supplements for pets undergo less regulatory oversight than human dietary supplements. A branch of FDA, the Center for Veterinary Medicine (CVM), is responsible for the regulation of animal food products. Companies are free to advertise claims of improving health. While CVM may take action against violations of policy if there is an adverse event, there is no standardized monitoring system in place to ensure accountability of a manufacturer.
One study discovered that chondroitin sulfate, an expensive ingredient derived from shark and bovine cartilage for treating osteoarthritis in canines, was inappropriately labeled in 84% of products in the study and mislabeling went as high as 115%. Consumer Laboratory (www.consumerlabs.com), a for-profit laboratory, offers testing and validation for pet and dietary supplements. Within their joint supplement category for animals, only two of the four joint products for dogs and cats were approved for quality.
“I as a veterinary pharmacist do not recommend supplements to pet owners,” said Elaine Blythe, PharmD, associate professor of veterinary pharmacology at St. Matthews University, School of Veterinary Medicine, Grand Cayman Island and adjunct professor at the University of Florida College of Pharmacy. “I believe such recommendations should be made by veterinarians who evaluated the pet and made treatment recommendations based upon their diagnostics.”
Most veterinarians are cautious and reluctant to recommend these products, especially since they are legally liable should they recommend a pet supplement that leads to adverse effects.
What to tell your patients
Pharmacists should be familiar with the most common supplements used in pet patients, said Blythe. “A likely case is when a vet instructs an owner to go to the pharmacy and acquire milk thistle as part of the outpatient treatment and recovery for a dog diagnosed with a hepatotoxin. In this case, because the attending veterinarian instructed the owner to acquire the supplement, the owner may then ask the pharmacist where to find the product in a pharmacy, administration suggestions, or possible adverse effects,” said Blythe.
Pharmacists can share their knowledge of adverse effects management, drug–drug interactions, and serve as a liaison with a veterinarian, helping pet owners navigate the world of pet supplements or administering medications.
Blythe recommends Plumbs Veterinary Drugs (plumbs.com), a subscription-based comprehensive veterinary drug reference that can guide pharmacists in real time when answering such questions. “Pharmacists can use this easy-to-navigate reference to help them safely and accurately dispense FDA-approved medications,” said Blythe. ■