When is compounding necessary?

Compounding for non-food animals may be necessary when approved drugs need to be modified to sufficiently treat the patient (e.g. flavoring, diluting, or changing the form of medications from tablet to suspension).For example, if you need to prescribe methimazole (Felimazole®) for a hyperthyroid cat but the owner tells you the cat will not allow the owner to “pill” it, you might need to have the product compounded into a liquid form so the cat can be adequately treated.

Compounding for non-food animals might also be necessary when no approved drug exists, or if the approved drug isn’t commercially available to treat a pet’s diagnosed condition. There are two general sets of circumstances in which the AVMA believes compounding from bulk ingredients (i.e., “raw” active ingredients) may be necessary:

  • the approved drug is not commercially available, or
  • the needed compounded preparation cannot be made from the approved drug.


Do Compounded Drugs Have Expiration Dates?

Yes. But veterinarians should be aware that beyond-use dates and expiration dates are not the same. Expiration dates for the chemical and physical stability of compounded drugs are determined via rigorous analytical and performance testing. As a result, a product’s expiration date is specific for that particular formulation, in the container it is in, and at stated exposure conditions.


Can Controlled Substances Be Compounded? 

Yes. But the process not only needs to follow the FDA’s and the state’s rules, it will also have to follow the rules of the Drug Enforcement Administration (DEA). Therefore, you have to maintain a “closed distribution system,” in which the product is directly dispensed to the patient’s owner or caretaker.