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Do Opioids for Pets Increase Abuse Risks Among Humans?

January 11, 2019

Researchers recently found that an increase in opioid prescriptions among people may be directly associated with an increase in opioid prescriptions for pets. This study, published online in JAMA Network Open, was the first study of veterinary opioid prescriptions.

“As we are seeing the opioid epidemic press on, we are identifying other avenues of possible human consumption and misuse,” study senior author Jeanmarie Perrone, MD, professor of Emergency Medicine and the director of Medical Toxicology at Penn Medicine, said in a statement.

Together, researchers from the University of Pennsylvania’s Perelman School of Medicine and the School of Veterinary Medicine (Penn Vet) reviewed opioid pills and patches dispensed or prescribed for dogs (73%), cats (22.5%), and other small animals (4.5%) at Penn Vet from January 2007 through December 2017. More specifically, the researchers analyzed trends for four opioids prescribed or dispensed to animal patients, including tramadol, hydrocodone, and codeine tablets, and fentanyl patches.

According to the results of the study, the researchers found that the quantity of these prescriptions, as measured in morphine milligram equivalents (MME), rose by 41% during the period annually. Further, the annual number of visits rose by 13%.

“Even where the increase in prescribed veterinary opioids is well intended by the veterinarian, it can mean an increased chance of leftover pills being misused later by household members, sold or diverted, or endangering young children through unintentional exposure,” Dr Perrone explained. “The results of this study suggest that by assessing the rate of veterinary opioid prescriptions, we can develop strategies to reduce both human and animal health risks associated with increasing use.”

Currently, some states have added restrictions to veterinary prescribing in an effort to control opioid dispensing. Some of the restrictions include background checks on animal owners’ opioid prescription histories in Maine and Colorado. Further, Alaska, Connecticut, and Virginia now limit the number of opioids any one veterinarian can prescribe to a single animal patient.

“At the national level, we don’t know the potential or extent of prescription diversion from animals to humans, and what impact this could have on the human opioid crisis,” said lead author Dana Clarke, VMD, an assistant professor of Interventional Radiology at the University of Pennsylvania’s School of Veterinary Medicine.

Julie Gould


Clarke DL, Drobatz KJ, Korzekwa C, et al. Trends in Opioid Prescribing and Dispensing by Veterinarians in Pennsylvania [published online January 11, 2019]. JAMA Netw Open. 2019;2(1):e186950. doi:10.1001/jamanetworkopen.2018.6950.

Penn Medicine. Does Opioid Use in Pets Create Higher Risk for Abuse in Humans? [press release]. Accessed January 11, 2019.

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