Equine Canada has issued a reminder to equestrians to use compounded medications with caution, and only under the proper guidance and prescription of a veterinarian.
Several positive tests are under review by the Equine Canada Equine Medication Control Committee (EMCC). It said these results may be related to the administration of compounded drugs, although no disciplinary rulings have yet been determined.
Compounded drugs are products that are specially formulated by a pharmacy or veterinarian because they are not available as a licensed product, they may contain different concentrations or composition compared to a licensed product, or they may be less expensive. Their use must take into account the concentration of the active ingredient, route of administration, safety and the possibility of contamination.
Equine Canada stressed that approved drugs must meet Health Canada standards, but the same level of control for compounded drugs does not exist. There have been instances where compounded drugs have had greater concentrations of the active ingredient than what was stated on the label or have had additional ingredients not stated on the label. In May, two batches of medication used to treat the neurologic disease Equine Protozoal Myeloencephalitis (EPM), were associated with adverse events in 10 horses.
Even if higher than labeled concentrations do not have adverse health effects, they could cause a horse to have a positive test result by exceeding the allowed limit for a permitted medication or prolonging the detection time of a prohibited substance beyond the guidelines. Positive test results in such cases remain the responsibility of the Person Responsible for the horse or pony.