Horse Owners: Use Caution with Unapproved Drugs

A recent outbreak of human meningitis, caused by the injection of contaminated compounded steroid products prepared by the New England Compounding Center, has put compounding pharmacies into the daily headlines. With a death toll reaching 39 and a reported 656 cases nationwide as of late December, the outbreak has likely raised questions in consumers' minds about drug safety.

But it isn't just human drugs consumers should be concerned about. Compounding pharmacies prepare drugs for horses, as well. In 2009, a vitamin and mineral supplement prepared by Franck's Compounding Lab in Ocala, Fla., included an excessive amount of one ingredient (selenium) that resulted in the death of 21 polo ponies. In other cases of questionable drug safety, illegal products that claim to be "the same as" name brand drugs are marketed to consumers, sometimes with devastating results. In 2006, a reported six horses died as a result of using an illegal clenbuterol product.

In other instances of using non-U.S. Food and Drug Administration (FDA) approved drugs, while the products might not be particularly harmful, they might not contain the labeled amount of active ingredient or do what they claim to do.

Studies presented at the American Association of Equine Practitioners (AAEP) Convention in prior years have shown a wide range in the pharmaceutical equivalence of compounded drugs when compared to brand name drugs. In 2003, Scott Stanley, PhD, director of the University of California, Davis, Kenneth L. Maddy Equine Analytical Chemistry Laboratory, presented findings from a study evaluating compounded versions of the FDA-approved drugs ketoprofen, amikacin, and boldenone. In the case of ketoprofen, one compounded preparation contained just one-half of the expected concentration. With amikacin, some compounded preparations had a lower drug concentration, between 59% and 76% of what was stated on the label. Other compounded versions of the drug had 112% and 140% of the stated concentration.

Stanley conducted similar research on compounded versions of omeprazole and presented his findings at the 2011 AAEP Convention. The compounded omeprazole products ranged from more than 100% to approximately 63% of the concentration stated on the label. After 60 days, the compounded versions lost potency, with the amount of active ingredient varying from 82% to as little as 17%.

At the 2012 AAEP Convention, Stanley presented results from a similar study, this one comparing compounded formulations of clenbuterol with the FDA-approved version. His findings showed the compounded formulations varied from containing as little as 32% of the labeled concentration up to more than 316% of the labeled concentration.

"What these studies have shown is that compounded versions of equine drugs, in many cases, do not contain the proper concentration of the active ingredient," says April Knudson, DVM, equine specialist for Merial Large Animal Services. "If they don't have enough of the active ingredient, it's a natural conclusion they won't work as well, if at all. If they have too much of the ingredient, it's possible there will be a detrimental effect on the horse's health, depending on the ingredient."

Containing the same active ingredient as a brand name drug does not guarantee a product's efficacy or safety. A proper formulation is often an essential part of making a safe and efficacious product.

By using FDA-approved products, horse owners will be using drugs that are:

  • Tested in the target animal in field trials and in the laboratory;
  • Manufactured according to Good Manufacturing Practices, which ensures consistency;
  • Manufactured in inspected facilities that meet FDA guidelines;
  • Labeled with information that can be scientifically substantiated;
  • Advertised in such a way as to not be false or misleading; and
  • Monitored following approval for adverse events.

Because some unapproved drugs are made to look like the approved drugs, horse owners should be wary and do their homework. To determine whether a product has been FDA-approved, owners can check the searchable database at AnimalDrugs@FDA. Most generic and brand name drugs also feature a number on the label indicating FDA approval. In the case of brand name drugs, look for the six-digit New Animal Drug Application (NADA) and for generics, the Abbreviated New Animal Drug Application (ANADA) number.

"Horse owners have a lot of financial and emotional investment in their horses," says Knudson. "Taking some time to research the products available and make educated decisions should help them keep their horses healthy in the long run."

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