Is Your Horse Getting the Right Medications?

Unethical medication production and marketing is a serious problem in the equine industry, said Joe Bertone, DVM, MS, Dipl. ACVIM, in a presentation at the American Horse Publications convention on June 21. "The equine industry is a huge target for snake-oil salesmen," he stated. "There is more 'stuff'--and that's being nice--propagated in equine medicine than in any other field I've experienced."

The problem isn't with major manufacturers. Rather, it's with unethical compounders (not to be confused with ethical ones) and manufacturers who skirt the regulatory system in order to sell cheaper, often less potent products to unsuspecting owners and veterinarians. Having sub-optimal levels of active ingredients might not hurt your horse, but what could hurt or even kill him is not getting the right type and dosage of a medication he needs.

In the U.S., there are three classifications of equine medications. These include:

Food and Drug Administration (FDA)-approved pioneer drugs--These drugs are the original ones researched and developed by major manufacturers at a cost of $10-20 million per equine product.

FDA-approved generic drugs--These must have the same chemistry and manufacturing as the pioneer drugs with which they compete, but their manufacturers aren't required to conduct safety/efficacy testing. The generic form must be "bioequivalent" to the competing pioneer drug, meaning it must have the same quality of ingredients and pharmacokinetics.

Compounded drugs--These drugs are manufactured by pharmacies or individuals, carry no FDA approval status, and are not required to adhere to Good Manufacturing Practices (GMPs). Sometimes they are safe and necessary, but quality should be questioned in this class of drugs as compared to FDA-approved drugs.


The Animal Medicinal Drug Use Clarification Act of 1994 states that it is illegal to produce a compounded drug designed to treat a disease or condition when an FDA-approved drug for the disease or condition is available. As an exception to this rule, compounding a particular drug is legal when the approved drug is not available in the required dosage form or concentration.

"I'm a big supporter of this practice," Bertone said. "This is an essential need in veterinary medicine because there aren't enough FDA-approved drugs in useful formulations for horses."

One problem is the amount of active ingredient in the product. Compounded drugs have been found with as little as 6% of the active ingredient claimed on the label, whereas FDA-approved products must have a minimum of 90% of their labeled values. For example, one study of 11 compounded ivermectin products found unacceptably low levels of ivermectin in all but one. Aside from ineffectiveness, this kind of dosing contributes to parasite resistance by delivering non-lethal amounts of the drug.

A few products with higher amounts than those labeled have been found; depending on the drug's toxicity level in the horse, this could be worse than ineffectiveness.

"Cheaper" pharmaceutical materials used to make compounded products might be of lower quality, or might not even be the materials requested, explained Bertone. For example, clenbuterol (a bronchodilator) has been replaced with albuterol--which sounds the same, but isn't used at all by the horse when administered orally.

Some veterinarians sell cheaper compounded drugs to clients at a price similar to that of the FDA-approved drugs. This practice is forbidden by federal regulations.

"The typical comment is that compounded drugs are less expensive," said Bertone. But he said that using
compounded products when there are approved medications is "inappropriate, unscientific, and unethical." He also noted that using these "knockoff" products rather than approved ones decreases the incentive for medication development by pharmaceutical companies. Buying it because it is cheaper is sound logic only if the approved drug is a human drug that is too expensive.

What about regulation? "The FDA is much more concerned with food animals," Bertone explained. "There is very little compounding in that industry. We need the public and veterinarians to be aware of this problem (in the horse industry); that will stop more of this than the government can touch."

Spotting Snake Oil

Horse owners should check with their veterinarians on whether compounded products are being used, and if so, whether the veterinarian trusts this compounder to make quality medications.

"Call and ask if the company compounds ivermectin (or any other product that's approved for horses and doesn't need to be compounded)," he suggests. "If they do, don't use them."

Also look for an expiration date on a compounded product. "Regulations state that a medication must have an expiration date no later than three months after its manufacture," he said.

Look for a label that states that the drug is sterile. "No compounded injectable drug can say that it's a sterile solution, because that implies direct testing (the procedure for which can contaminate the sample)," Bertone explained.

For more information, see Article Quick Find #3649 at

About the Author

Christy M. West

Christy West has a BS in Equine Science from the University of Kentucky, and an MS in Agricultural Journalism from the University of Wisconsin-Madison.

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