To estimate the number of patients linked to vet-shopping behavior (the solicitation of controlled substance prescriptions from multiple veterinarians for misuse) in the United States using 2014-2019 data and characterize mandates for veterinarians to examine prescription drug monitoring programs (PDMPs) before prescribing controlled substances as of April 2021. National database reporting prescription dispensing from 92% of US pharmacies from 2014 through 2019. The annual number of patients with dispensed prescriptions for opioid analgesics, opioid cough-and-cold medications, or benzodiazepines from ≥ 4 veterinarians was calculated. State veterinary medical associations were contacted for information on veterinarian PDMP use mandates. From 2014 through 2019, the number of patients with prescriptions for any class of controlled substances from ≥ 4 veterinarians tripled from 935 to 2,875 (+207.5%). The number of patients with opioid cough-and-cold medication prescriptions from ≥ 4 veterinarians rose from 150 to 1,348 (+798.9%). The corresponding number for benzodiazepines rose from 185 to 440 (+137.8%). The corresponding number for opioid analgesics peaked at 868 in 2016 before decreasing to 733 in 2019. In April 2021, 10 states mandated veterinarians to examine PDMP records of owners or animals before prescribing controlled substances; 3 mandates excluded benzodiazepines. Vet shopping in the US may be increasingly common. Mandates for veterinarians to examine PDMPs before prescribing controlled substances might facilitate detection of this behavior. However, benefits of mandates should be weighed against their potential burden on veterinarians.