All of the drugs that are approved for use in animals are approved by the FDA.  The FDA’s center for veterinary medicine monitors all reports of adverse drug events with any drug, medicated feed, or veterinary device used on animals.  Adverse drug events are not only undesired effects such as reactions, but also lack of a desired effect.  Any such reaction should be reported to the FDA. 

The reporting of adverse reactions has increased considerably as the number of reports increased from 4000 in 1997 to 24000 in 2001.  This increase is not due to more reactions, but to ease of reporting with a data base that allows rapid entry of information. 

Typically, new animal drug manufacturers invest years and millions of dollars developing protocols and submitting data showing safety and efficacy to the FDA for a new animal drug.  Safety means not only safe for the animal, but also for humans handling the drug, humans consuming tissues containing the drug in the case of food animals, and safe for the environment. 

After approval, the FDA monitors these drugs closely.  One example of this monitoring is the report of blindness in cats caused by the drug enrofloxacin at the approved dose.  The dose was too high for cats and the dose was changed.  Also, the drug etodolac was found to cause decreased tear production in some dogs.  Tear production became normal after stopping the drug.  Many of the non steroidal anti-inflammatory drugs for arthritis have been shown to cause kidney, liver, and gastrointestinal problems after approval. 

If you observe an unusual animal drug reaction, it is important to call your vet and report the reaction to the FDA at 1-888-FDA-vets.