This site is no longer being updated. Read more on pet behavior and wellness at The Wildest.

Dog Meds: From Supplements to Compounded Drugs and Generics

What should we be looking for?
By Sheila Pell, March 2016, Updated August 2021
dog with vet

When it comes to giving a dog a pill, a tasty disguise is often in order—trickery helps deliver the goods. But what if the dog isn’t the only one being fooled?

Sales of pet supplements are soaring, prescription drugs (“no prescription required”) are just a click away, and pharmacies are creating compounds tailored to a dog’s individual needs. Yet, tests keep proving that remedies aren’t always what their labels claim.

Veterinary drugs are federally regulated, but supplements fall into a regulatory abyss. In both cases, critics say, oversight is lacking. While Internet shoppers risk buying fake, unapproved and contaminated products, tainted pills can also be found on store shelves and in pharmacies.

Access to affordable medications is another issue. Can’t find a generic version of that expensive drug? It may be hidden in plain sight, thanks to covert efforts to block it.


Sign up and get the answers to your questions.

Email Address:

Supplements, More or Less
When it comes to their dogs, Americans spend more on vitamins than on either toys or treats. A 2015 survey by the American Pet Products Association finds that annual expenses are $62 for vitamins, $61 for food treats and $47 for toys.

This boom follows a recession-era slump, according to market-research firm Packaged Facts. Riding in on the wave is a stream of “natural” and organic supplements targeting obesity, aging and joint health. But sales of these products still lag behind sales of nutraceutical treats like functional biscuits (which also offer taste appeal), so companies are shaping their ingredients into new liquids, powders, gels and pastes.

All of which suggests that more dogs will be given questionable products.

“It is definitely a buyer-beware situation for pet owners,” says Tod Cooperman, president of, an independent testing company that keeps tabs on health supplements. When the company started in 1999, defective vitamins were making news, but there was little testing. “I realized that consumers needed more information,” says Cooperman, who began the venture with former FDA chemist Dr. William Obermeyer.

In 2003, the lab analyzed its first pet-specific product, the popular joint-care staples glucosamine and chondroitin. “We found two supplements which had no chondroitin despite a guaranteed analysis on the labels showing significant amounts.” While many people think such work is the job of the FDA—or, for pets, the Center for Veterinary Medicine (CVM)—it’s up to manufacturers to test for safety and follow good manufacturing practices. Federal rules don’t recognize pet supplements at all unless companies put them in food or claim they treat illness.

“Government oversight of the manufacture of supplements for people is minimal; oversight of supplements for pets hardly exists,” Cooperman says. “In general, a lower percentage of pet supplements pass our reviews of quality.”

The problem is compounded (no pun intended) by the fact that China, origin of many tainted pet products, is the world’s leading supplier of nutritional raw materials. But issues with ingredients aren’t confined to any one country, and mistakes can occur at various points in the manufacturing process. According to Cooperman, “A pet owner is trusting the supplement maker to formulate a product with the right amount and type of ingredients, and to make it properly without contamination.”

Recently, ConsumerLab tested five kinds of pet supplements: probiotics, joint health products, fish oils, plant-based oils (like flaxseed) and multivitamins.

Tests of three probiotics for dogs and cats found that two had high amounts of the beneficial organisms, more than one billion per daily serving, as claimed. However, Cooperman says, the third contained such a small amount that its efficacy is highly questionable. As with previous testing, products for veterinary joint health fared poorly. None of them had exactly what they claimed. Three contained only 16 to 76 percent of the listed glucosamine. One exceeded its label, packing 36 percent more MSM, an anti-inflammatory compound. Could the excess be harmful?

“It’s okay for companies to add a bit more ingredient than listed, but not that much,” Cooperman notes, adding that it suggests “a possible manufacturing issue.” Of greater concern was another product that provided only 16 percent of its listed chondroitin, a particularly expensive ingredient. “We’ve been finding pet supplements short on it for many years.”

He notes that two joint-health products voluntarily tested in the website’s rigorous certification program passed, receiving the “Seal of Approved Quality.” The lab buys the samples from brick-and-mortar or online stores, as a consumer would. “Manufacturers can’t send us products. This way, the quality we find is likely to represent what [consumers] are getting off the shelf,” he says. The seal, good for one year, applies to a particular product and can only be used in conjunction with that product.

Of the fish oils, all three did well, Cooperman reported. They contained plentiful omega-3 fatty acids, EPA and DHA. Both plant oil supplements for skin and coat also passed. But potency aside, what about contaminants like mercury, which could easily be far higher in products for animals?

“We test all fish oils for mercury and other heavy metals, [including] lead, cadmium and arsenic,” he says. “The good news is that we have not found mercury in fish oil.” That’s because mercury binds to fish muscle, not fat, and the oils are purified. The bad news: “We have found higher levels of PCBs in some fish oil for pets than in those for people. PCBs (polychlorinated biphenyl) are carcinogens and can have other harmful effects.”

In the pet multivitamin category, all three products flunked across the board. One had just 30 percent of the vitamin C listed on the package. Another contained only 52 percent of the vitamin A it claimed. And one, the worst example of mislabeling, had a mere 16 percent of the vitamin C and only 7.5 percent of the vitamin A it touted.

As ConsumerLab keeps proving, these aren’t isolated incidents. “We believe that the FDA is aware of our findings, but if serious injury is not being reported, they are unlikely to take action. It’s up to consumers to educate themselves and purchase wisely. I recommend that people see what’s passed our tests,” Cooperman advises. (For the cost of a subscription, consumers can access test results on the company’s website.)

Still, online shopping is a gamble even with brand names; the FDA warns that unscrupulous companies are selling fake or otherwise mislabeled pet supplements. Cooperman says that Internet sites seem more focused on customer service than product quality, and, “Unfortunately, you can’t just rely on a brand to always produce good products. There are plenty of products that have failed miserably in our tests, yet continue to be sold.”

Compounding for Better and Worse
Who would give their dog a drug that hasn’t been safety tested?

As it turns out, a lot of people. Sometimes, a dog needs a medication that’s not readily available. Once a dilemma, with a vet’s prescription, the answer is now often found at a compounding pharmacy. Think custom drug. Does your pup manage to eat the treat and spit out the pill every time? Turn the pill into a tasty liquid.

It can also allow more exact dosing. Say your dog needs a 45 mg dose of a drug that only comes in 10 mg or 40 mg capsules. No need to round it down to 40 mg, the usual solution; compounding can yield the ideal strength.

It might seem that such precise formulas would be safer and more effective. But that’s not always so. For one thing, while the drugs they’re made from are FDA-approved, compounding (by mixing, diluting or other changes) yields a whole new product. The resulting drug isn’t safety tested, FDA-approved or even sure to work. It’s pharmaceutical roulette — as injuries, deaths and recalls have shown.

How can it go wrong? The list is long: with sanitary problems, like the deadly 2012 human outbreak of fungal meningitis linked to a high-volume compounding pharmacy; with too much of one drug along with unapproved drugs used in a combination, which killed several horses in 2014; with drugs prescribed for owners that can be fatal to pets, seen with compounded pain creams last year (in cats, but dog owners were also alerted); and with solutions that deteriorate before the expiration date, as was found—along with a “five-fold compounding error”—in a study of compounded medications for dogs.

In a recent study, University of California, Davis, veterinary researchers report another disturbing glitch. CCNU (lomustine), a drug their hospital relies on, is a staple in the treatment of cancers such as mast cell tumors and lymphoma. When drug companies run out, the university’s vets turn to compounding pharmacies. That’s what happened in 2013; then, they noticed something odd.

Animals treated with the compounded CCNU weren’t showing the usual drop in the number of white blood cells the drug is intended to achieve, while every animal given the FDA-approved version did have this result. Tests found that the strength of the compounded capsules varied widely. Some had only half what their labels claimed.

With chemotherapy, there’s a very a narrow margin between an optimally effective and a toxic dose, the researchers say. That’s why compounded cancer drugs can improve treatment. The FDA regulated CCNU, for example, only comes in two strengths, a limitation overcome by the compounded version.

Also, compounded drugs are sometimes far cheaper. The UC Davis researchers say that a compounded version of an FDA-approved drug can sometimes be purchased for one-third of the cost of a brand name.

But quality-control issues can also arise when cost-cutting involves mass production of compounded drugs. The Massachusetts pharmacy behind the meningitis outbreak charged about two dollars less per vial for their drug, but they were illegally making drugs for broad use rather than filling individual prescriptions. This practice was soon exposed at other pharmacies as well.

FDA regulations generally allow compounding for animals using approved human or animal drugs, but not bulk active pharmaceutical ingredients. Oversight has mostly fallen to state boards of pharmacy. However, according to the International Academy of Compounding Pharmacists, only 17 states mandate following USP drug standards, strict guidelines set by the nonprofit U.S. Pharmacopeial Convention.

The UC Davis researchers, who are now investigating other chemotherapy drugs, agree that more oversight of compounding is needed. They advise veterinarians and owners to weigh the pros and cons of choosing a compounded formula over standard drugs, especially when treating cancer. Know the risks in getting a drug that’s weaker or stronger than expected. In chemotherapy, missing the target in either direction can be deadly.

Affordable Drugs
A generic drug is generally considered equal to the branded form (for example, acetaminophen is the generic stand-in for Tylenol). But one place they’re not equal is price, where generics are the clear winners for most shoppers.

There were few of these affordable options in 2006 when Maine’s Portland-based Putney, Inc., founded by Jean Hoffman, took up the challenge. While the lack of competition was good for drug companies, it didn’t bode well for animals, as Putney spokesperson Susan Hanley explains.

“With few veterinary generic options, many pet owners couldn’t afford their veterinarian’s recommendations, especially for drugs needed every day.” So vets would sometimes prescribe human generic drugs instead. Unfortunately, most pet drugs have no human version, she says, and for those that do, dosing can be off due to differing strengths or formats.

Putney was the first to develop generic prescription drugs specifically for veterinary use, Hanley says. “We know from a nationwide survey that 87 percent of pet owners would choose a veterinary generic of their pet’s medicine if their veterinarian offered one.”

Change has come slowly. A Putney analysis through 2014 found that 91 percent of all approved drugs for dogs and cats still have no generic equivalent. The company pushes on and to date, has landed a total of 10 CVM approvals for veterinary generic drugs. The approval signals that a generic pet drug is bioequivalent to the branded version, Hanley says.

Each drug they develop is made in a plant that also makes FDA-approved human drugs. To oversee products, their experts visit manufacturers of both finished drugs and active ingredients. While they don’t sell drugs to Internet pharmacy sites, Hanley notes, “they are often available there anyway.” Currently, the company has several drugs in development and review stages. She can’t reveal them, but says they have “some exciting new generics expected next year.”

Meanwhile, brand-name drug-makers haven’t been idle as other companies make more affordable versions of their products. Some are fighting back with blocking agreements, which Hanley calls “unusual contracts in the pet drug market, signed by a branded veterinary drug company and all the national distributors serving veterinary clinics.” The brand company lets distributors profit from a list of drugs veterinarians often prescribe, with one caveat: they must promise not to carry any generic version of the brand drug.

According to Hanley, the first such agreement was put in place by Zoetis (under the predecessor name Pfizer Animal Health) in 2005, right before initial approval of a generic for Rimadyl, the company’s popular arthritis treatment for dogs. “We also have verbal evidence that blocking agreements have been in use by various brand companies since 2005,” she says. “The contracts block vets, and their pet-owner clients, from gaining the cost savings of FDA-approved generics.”

While the cost of generic medications has shot up in recent years, generics are still typically cheaper than the brand-name version. Since statistically, companion animals are living longer, obstacles to obtaining cheaper drugs have a greater potential impact. Price can be a barrier when it comes to treating a dog or cat’s chronic condition, and if the animal’s health is fragile, their lives may depend on consistent access to a medication.

The pill market is full of pitfalls. Those who turn to supplements to ease ailments, or in the hope of avoiding the need for drugs in the first place, also gamble. Here’s the proverbial bottom line: reduce the risks by remaining vigilant and taking the advice of experts.

Photo: iStock

Sheila Pell is a freelance journalist who frequently writes about environmental issues. Her work has appeared in The Washington Post, Modern Farmer, San Diego Reader, The Bark, and American Forests. She lives in northern California with her husband and two large dogs.