Compounding: FAQ for Pet Owners

Q: What is compounding?

A: Simply put, compounding is any manipulation of a drug beyond that described on the drug label.

Manipulation might include mixing, diluting, concentrating, flavoring, or changing a drug's dosage form.

Veterinary drugs should only be compounded based on a licensed veterinarian's prescription, and to meet the medical needs of a specific patient. Examples of compounding include:

  • mixing two injectable drugs in the same syringe;
  • creating an oral suspension from crushed tablets or an injectable solution;
  • adding flavoring to a commercially available drug;
  • creating a skin-penetrating gel for a drug typically taken through other routes;
  • mixing two solutions for instilling into the ear.

Q: When is compounding necessary?

A: Compounding is usually necessary when an animal is suffering from a medical condition and there is no FDA-approved human or veterinary product available and medically appropriate to treat the patient. The decision to use a compounded preparation must be medically necessary and made within the confines of a veterinarian-client-patient-relationship.

For example, a cat needs a medication that is only available in a pill form. If the cat's owner is unable to administer the pill at home, the veterinarian might have the drug compounded into a flavored liquid that the cat will take.

Realize that although compounds might be necessary in some medical situations in pets, there are benefits and risks to their use. Because compounded preparations are not approved by the FDA, there is no assurance of how well they can be expected to work (e.g., safety, potency, stability, efficacy). That's why it's best to use an approved drug, but that is not always possible and compounded medications play an important role in animal health.

Q: How do compounded medications differ from the manufactured, FDA-approved ones I can get from a pharmacy or supplier?

A: According to the U.S. Food and Drug Administration (FDA), federal rules currently require that compounded medications only be modified versions of FDA-approved medications. In other words, compounded medications should only be prepared using FDA-approved drugs that have been crushed, had a flavor added or otherwise changed from the original form. If they are made from ingredients that are not already approved by FDA for humans or animals, then FDA considers these preparations to be "new animal drugs," which are required to have FDA approval in order to be legally sold.

For example, let's say your animal has a unique condition that needs to be treated with eardrops, but the FDA-approved drug your pet needs is only available as a tablet. Your veterinarian can ask a compounding pharmacy to create an eardrop version of that tablet so your animal can get the treatment it needs.

In some situations veterinarians may find it necessary to compound from a source that has not been approved by the FDA to relieve the animal's suffering. In these cases, veterinarians and pharmacists must carefully assess whether the use is consistent with state and federal law and FDA policy.

The federal government is currently assessing how compounding rules should be clarified further. We will update these FAQs as new information becomes available.

Q: Are compounded drugs the same as generic drugs? How can I tell the difference?

A: No, they are not the same. A generic drug is a non-proprietary-name version of a drug: for example, Tylenol® (McNEIL-PPC, Inc.) is a brand name (for use only in people, never in pets), but acetaminophen is the non-proprietary name (most commonly called "generic"). In general, buying a non-proprietary drug with the same ingredient and same strength as the brand name is equivalent to (but often cheaper than) buying the brand name version. We are aware, however, that there are individuals who seem to respond better to either the brand name or generic version, so there can be some variation.

The non-proprietary, or generic, drugs that you obtain from your veterinarian or a pharmacy are approved by the FDA. They have been shown to be safe and effective, their label has been approved by the FDA, and their manufacturing facilities follow certain FDA specifications. The manufacturer is also required to continually ensure the shelf stability of the product as well as prove that it will be absorbed into the patient's bloodstream (bioavailability). Non-proprietary animal drugs have an Abbreviated New Animal Drug Application (ANADA) number given to them by the FDA, which you can often find on the packaging.

When a drug is compounded, the new form of that drug may not perform in the same manner that the FDA approved drug does. Yes, it still incorporates the same drug ingredient, but it has been changed and you can't expect it to be identical in every way to the original drug. Therefore, the government considers compounded preparations to be drugs that they have not reviewed or approved.

Q: What drugs are most commonly compounded for use in animals?

A: Common examples of appropriate compounding in veterinary practice are mixing two injectable drugs, preparing an oral paste or suspension from crushed tablets or adding flavoring to a drug. One of the most common examples of compounding for animals is modifying an FDA-approved tablet or capsule into an oral suspension; for example, crushing a tablet and adding a tuna fish flavor to make it a palatable liquid.

Other frequently compounded preparations include cisapride (a drug that enhances gut movement), metronidazole benzoate (an antibiotic) and apomorphine (a drug used to induce vomiting). While often compounded and medically necessary for successful treatment of certain conditions, these four preparations are actually not examples of legal compounding as defined by the FDA. Federal regulations require that compounded preparations be created using an FDA-approved drug as the starting ingredient. Since there is no FDA-approved product to start with in preparing these compounded medications, an active pharmaceutical ingredient (i.e. raw chemical) must be used to prepare the medication.

In addition to these four examples, some other medically necessary drugs, such as poison antidotes, are only available as compounded preparations made from active pharmaceutical ingredients (API).

Q: How is compounding regulated?

A: It's regulated by both the federal government (Food and Drug Administration/FDA) and state governments. At the federal level, the FDA regulates compounding as a subpart of its Extralabel Drug Use (ELDU) Rules (the legislation is called the Animal Medicinal Drug Use Clarification Act of 1994). FDA also has a Compliance Policy Guide (CPG) which describes how it regulates compounding and what activities it defers to the state. The FDA says it generally defers day-to-day regulation of veterinary compounding by veterinarians and pharmacists to state authorities.

The United States Pharmacopeial Convention (USP) is a private, non-profit standard setting organization that establishes quality standards for both manufactured drugs and compounded drugs in the United States. USP has standards to ensure proper quality, purity, identity and strength when preparing compounds. It is important to note that USP standards for compounds do not require proof of safety or efficacy. Only FDA approved drugs carry assurance of safety and efficacy if used as labeled.

Q: What is known about the safety and efficacy of compounded medications?

A: There is no assurance, like there is with an FDA-approved drug, that a compounded medication will be safe or effective for an animal's medical condition. Because compounded preparations have not been evaluated and approved by the FDA, there can be some risk associated with their use. The safest and most effective choice is to use an FDA-approved product whenever possible and to only use compounded medications when your veterinarian has determined it is necessary for your animal's health. Your veterinarian can also discuss signs and symptoms in your pet that will alert you to any unintended effects that are caused by a compounded drug.

Q: When is compounding legal? What criteria must be met?

A: Compounding is considered legal when federal and state rules are followed. Requirements include an established Veterinarian-Client-Patient Relationship (VCPR); the individual patient has a medical condition for which a prescribed medication is needed; and the veterinarian determines that a compound is needed for the animal.

An example of compounding that would be considered legal is when a veterinarian mixes amikacin, which is FDA approved, with glycerin to make a drug mixture appropriate for treating certain resistant bacterial ear infections.

Q: When is compounding a problem?

A: Examples of situations where FDA has indicated it might take action to enforce the law include:

  • manufacturing a compound that's identical to an FDA-approved drug using commercial-scale equipment to compound in large quantities (compounding should be done on an individual patient basis); and,
  • compounding medications for third parties (including veterinarians) to resell to different patients.

The International Academy of Compounding Pharmacists, which is a non-profit association representing compounding pharmacists and technicians, has created a Code of Ethics for its members to follow, which addresses misinformation and misperceptions about compounded drugs.

It's also important to realize that FDA-approved drugs should be used preferentially over compounded preparations in pets unless the approved drug is not available or the approved drug cannot or should not be used for some medical or safety reason. For example, in April 2012, the FDA issued reminders to veterinarians and pharmacists regarding the compounding of pergolide, a drug that controls problems associated with equine Cushing's disease. The letters were issued to help prevent illegal compounding and use of pergolide products that are identical to the FDA-approved, commercially-available product. FDA currently issued similar letters for 7 veterinary drugs including: pergolide (Prascend), trilostane (Vetoryl), phenylbutazone (Butazolidin), deslorelin (Sucromate), domperidone (Equidone), estriol (Incurin), and phenylpropanolamine (Proin).

As an additional example, there is an FDA-approved product in paste form for treating stomach ulcers in horses. Any compounding pharmacy that manufactures what they call "generic Gastrogard" in a paste form is making an illegal product because they are purposefully duplicating an already-approved product. Gastrogard® contains omeprazole (also found in human products such as Prilosec®) and was proven effective in clinical studies. In one study compounded omeprazole was found to be ineffective when compared with the FDA-approved version (for a write-up about the study, view the article on While it might appear to be less expensive to buy a compounded copy of an approved drug, in the long run it presents a risk to your pet's health and can cost more correcting problems caused by an illegal copy of an approved drug.

Q: Can I use a compounded form of an approved medication because it's cheaper?

A: If you use a compounded medication only because it's cheaper, you could be putting your animal's health at risk by preferentially using a drug that hasn't been shown to be safe and effective. The FDA did a study in 2006 which showed that there are wide variations in efficacy of compounded medications. There are times when compounding may be necessary, but it isn't necessary when there's an FDA-approved drug that can adequately treat your animal's condition. As previously mentioned, you really do not save money by buying a manufactured mimic, because if the compound fails to do what the approved drug does, you might end up spending more money in the long run to treat your animal correctly.

Q: Are there different compounding rules/regulations applied to use in food-producing animals?

A: Yes, and those rules are much more strict because of the need to prevent potentially harmful residues in the meat, milk or eggs that come from the treated animals. FDA-approved products have a determined withdrawal time, which is the time from when the animal was last treated with the drug to when the animal can be slaughtered for food or the animal's milk can go to market. The withdrawal time of a compounded product is unknown because it hasn't been studied. The FDA's Extralabel Drug Use Rules and Compliance Policy Guide must be followed.

Q: My veterinarian has determined that my pet/animal needs a compounded medication. Where do I get that medication?

A: Sometimes your veterinarian's office can compound it for you (if legal in your state) or they will provide a prescription and refer you to a compounding pharmacy.

Check whether the compounding pharmacy you're considering is licensed within the state. Visit the National Association of Boards of Pharmacy (NABP) site for a link to all state and territorial boards of pharmacy. Most states have an online resource where you can identify which pharmacies are licensed to do business within the state. Some might also find it helpful to see what compounding pharmacies in their state are accredited by the Pharmacy Compounding Accreditation Board.

Q: Can I use a compounded medication for another pet/animal I own?

A: No, you shouldn't, unless your veterinarian has specifically directed you to do so. Prescriptions for compounded medications are specifically written for individual animals; using one pet's compounded medication for another pet could harm your pet. Only a veterinarian can prescribe for a medication to be compounded for an animal, so giving the compounded medication to another animal is essentially practicing veterinary medicine without a license.

Q: How can I know that a compounded medication is safe for my pet/animal?

A: There is no assurance, like there is with an FDA-approved drug, that a compounded medication will be safe or effective for an animal's medical condition. Therefore, the use of compounded medications is only recommended when an FDA-approved medication is not available in the appropriate formulation. When using compounded preparations, the best way to ensure your pet's safety is to discuss with your veterinarian signs and symptoms of an adverse reaction. Also, if the appearance of the compounded medication changes (color change, odor change, consistency change) while you are using it, you should stop using it and call your veterinarian immediately.

Q: What are the risks associated with the use of compounded medications?

A: Compounded medications have not been tested for safety and efficacy like FDA-approved drugs. During research and development of a medication, drug manufacturers conduct FDA-required tests to demonstrate to the satisfaction of the FDA that their product is effective and safe. FDA evaluates the data before approving the drug and allowing it to be put on the market. This is not the case with compounded medications since they have not undergone FDA's rigorous approval process.

Q: Can I get a compounded medication without a prescription?

A: No. Only a veterinarian can prescribe a compounded medication for an animal. Any unlawful practices, such as providing compounded medications without a valid prescription, should be reported to the state board of pharmacy.

Q: How can I find a compounding pharmacy that prepares high quality compounds?

A: Check with your state board of pharmacy for information on which pharmacies are licensed in your state. In addition, there are independent, third-party bodies (for example – the Pharmacy Compounding Accreditation Board) that accredit compounding pharmacies, ensuring they meet certain quality-assurance criteria. Your veterinarian is also a good source of information.

Q: How do I register a complaint about a compounded medication or a compounding pharmacy?

A: You can always report any problems with a compound (or any medication) to your veterinarian. After you contact your veterinarian, you or the veterinarian can contact your state board of pharmacy and state veterinary medical board to ask about the process to report suspected adverse compounding events or practices.​​