Understanding Controlled Substance Use in Pets

What are controlled substances?

Controlled substances include certain medications and illegal drugs that affect the brain and spinal cord (the central nervous system). These substances can be misused and can cause dependence in humans and animals. They may also cause severe side effects at high doses. Controlled substances are regulated by law to help ensure they are used safely and appropriately.

Most medications used in veterinary medicine are not controlled substances. However, veterinarians may prescribe controlled substances to treat certain conditions, most commonly to manage pain.

Are there different categories of controlled substances?

In the United States, controlled substances are divided into five categories, called schedules, based on their accepted medical uses and potential for abuse or dependence. Schedule I drugs have the highest potential for abuse and Schedule V drugs have the lowest potential for abuse among controlled substances.

In Canada, controlled substances are also grouped into schedules under the Controlled Drugs and Substances Act (CDSA). Both countries regulate controlled substances, but they group the drugs differently.

Why might my pet need a controlled substance?

Your veterinarian may prescribe a controlled substance to manage pain, provide sedation, or treat anxiety or other behavioral disorders.

What types of controlled substances are commonly used in veterinary medicine?

Controlled substances used in veterinary medicine include:

• Benzodiazepines (e.g., alprazolam)
• Certain sedatives and anesthetics
• Opioids (e.g., tramadol, morphine, hydromorphone, and fentanyl)

How are controlled substances prescribed for pets?

In the United States, federal and state regulations define when a veterinarian can prescribe controlled substances for a pet. Controlled substances must be prescribed by a licensed veterinarian who has established a valid veterinarian-client-patient relationship (VCPR). Your veterinarian may have additional requirements before they can prescribe or dispense a controlled substance for your pet. Changes in regulations may affect your veterinarian's ability to prescribe certain medications.

What risks are associated with controlled substance use in pets?

Controlled substances can help manage pain and other conditions in pets, but they also carry risks, including side effects and drug interactions. In addition, if the medication is not stored securely, someone may take or use it for a purpose other than treating your pet (potential for misuse or diversion).

What should I know about giving my pet controlled substances?

Follow your veterinarian's instructions carefully when giving your pet controlled substances, including how much to give and how to give it. Do not give your pet’s controlled prescription medication to another pet or person.

How should I store and dispose of controlled substances?

Store controlled substances out of reach of pets and children, in a locked cabinet or container that cannot be easily moved. Limit access to people who need to give your pet the medication. Keep track of how much medication remains so you can notice if any is missing. 

Dispose of unused or expired medication according to the instructions for that medication and local regulations. Ask your veterinarian about safe disposal options, such as a medication take-back program. Alternatively, your veterinarian may suggest mixing it with an undesirable substance (such as coffee grounds or cat litter) and sealing it in a bag before disposal.

What should I do if my pet ingests too much of a controlled substance?

If you suspect an overdose or your pet has a reaction to a medication, call your veterinarian immediately. If they are not available, follow their directions in contacting an emergency veterinary facility. Be prepared to provide information about the type and amount (or suspected amount) of medication ingested, as well as your pet's current symptoms.

How can I help ensure the safe use of controlled substances in my pet?

Discuss your pet's medical history, current medications, and any concerns you may have with your veterinarian. Follow your veterinarian's recommendations for monitoring and managing your pet's condition. If you have any questions or concerns, contact your veterinarian right away.

Where can I find more information about controlled substance use in pets?

Your veterinarian is the best resource for information about controlled substance use in pets. They can provide guidance based on your pet's specific needs and circumstances.

Controlled substances are often needed to manage pain and other conditions in pets and are relatively safe when used appropriately and under the guidance of a veterinarian. Be sure you understand the risks and responsibilities associated with controlled substance use and contact your veterinarian if you have any questions.