Ractopamine and Pigs: Looking at the Numbers

Due to a number of inquiries, we’ve decided to post the documents referred to in our January 25 report on msnbc.com “Dispute over drug in feed limiting US meat exports.”

The numbers used in our reporting came from a March 2011 summary Cumulative Veterinary Adverse Drug Experience (ADE) Reports, which were previously publicly available on the U.S. Food Drug Administration’s Center for Veterinary Medicine (CVM) website.

According to FDA, ADE reports include domestic adverse drug experience reports that have been submitted to that CVM and that the agency “has determined to be at least ‘possibly’ drug related.” The purpose of the database is to provide a warning and monitoring system for the agency on adverse effects that weren’t necessarily detected during the drug approval process.

The agency recently changed how it shares the summaries of ADE reports online. In the past, CVM has reported the number of animals involved in adverse reports, now CVM only reports the number of times a certain sign, e.g., “death” or “lameness,” is reported and they could involve one animal or thousands. The most updated summary report is available here. (Page 242 shows the numbers of reports for ractopamine given to pigs)

The March 2011 cumulative summary can be accessed via Archive.gov, a non-profit internet library that accesses and stores information from government websites. Here is a link to the archived report (click on N-S – ADE Summaries and see page 179), note that the page may take a minute or two to load.

According to this summary, 218,116 pigs have been evaluated in adverse reports submitted to the agency. The top ten most frequently reported signs were, “Death, Recumbency, Lameness, Hyperactivity, Reluctant To Move, Stiffness, Trembling, Dyspnea, Collapse, and Hoof Disorder.”

If you look at page 183 of the same document, another 2,143 pigs were evaluated for adverse reports for combination drug ractopamine and tylosin, which is an antibiotic approved for pigs and cattle.  The top ten most frequently reported signs for this combination drug were, “Lameness, Vocalization, Biting/chewing, Death, Hoof Disorder, Locomotion Disorder, Pain, Recumbency, Reluctant To Move, Shaking.”

Looking at the March 2011 data for each drug , A-Z , it is clear to see that there were far more pigs reported to be adversely affected by ractopamine than any other animal drug. The next highest number, 32,738 pigs, is for Tylosin.

As CVM notes on their website, there are limitations to ADE data. The reports vary in quality. For example, a farmer might call and complain about increased lameness or hyperactivity in pigs on ractopamine and not provide specific numbers. Or it may not be clear ractopamine necessarily caused the adverse effect.

However, the ADE reports provide the only publicly-available window into animal drug performance and adverse effects. In the case of ractopmine, there is no other adverse report data to look at. We filed a Freedom of Information Act request to get the details of each ADE report for ractopamine to look at them more carefully. In April 2011, the FDA released 464 pages of ADE reports, which included all classes of animals ractopamine is approved for: turkeys, cattle, and pigs. The ADE reports also include accidental human, dog, and horse exposures.

See a sample of these reports for pigs here, or download the full report here.

To help analyze these reports, we consulted with multiple independent animal scientists and veterinarians on ractopamine, including two researchers who have studied the drug’s impact on animal behavior and welfare (and one researcher whose study was submitted in an ADE report) to help augment the data weaknesses. We also looked at peer-reviewed research on ractopamine and animal behavior (see below).

Another key factor in the investigation of ADE reports was the circumstances under which FDA asked drug maker Elanco to add a warning label to ractopamine approved for pigs, commercially sold as Paylean, three years after the drug was approved by the agency. The warning label reads: “CAUTION: Ractopamine may increase the number of injured and/or fatigued pigs during marketing. Not for use in breeding swine.”

As reported in the msnbc.com article,  the company also received a warning letter from the FDA that year for failing to disclose all data about the safety and effectiveness of the drug.” (See the warning letter here or download the pdf here.)   We recently issued a clarification on the msnbc.com story to make clear that the adverse drug effects we cited for ractopamine were reported to the FDA. The story adds that the FDA says such data do not establish that the drug caused these effects.

More on ractopamine and pigs:

The effects of ractopamine on the behavior and physiology of finishing pigs – Journal of Animal Science, 2003

Effects of a “step-up” ractopamine feeding program, sex, and social rank on growth performance, hoof lesions and Enterobacteriaceae shedding in finishing pigs – Journal of Animal Science, 2008

Behavior and peripheral amine concentrations in relation to ractopamine feeding, sex and social rank of finishing pigs – Journal of Animal Science, 2009

Aggressiveness and brain amine concentration in dominant and subordinate finishing pigs fed the β-adrenoreceptor agonist ractopamine – The Journal of Animal Science, 2010

Why Ractopamine Increases Aggressive Behavior” July 14 2010