Clinical pharmacology of analgesic drugs in cattle.

Providing pain relief in cattle is challenging. In the absence of labeled drugs, the Animal Medicinal Drug Use Clarification Act regulates the extralabel drug use of analgesics in cattle within the United States. Given the variety of pharmacokinetic and pharmacodynamic properties of pain-relieving drugs, evidence needs to drive the development of analgesic protocols for cattle during pain-related events. This article reviews the commonly used analgesics investigated in cattle including local anesthetics, nonsteroidal anti-inflammatory drugs, opioids, α2-agonists, N-methyl-d-aspartate receptor antagonists, and gabapentin. These compounds are examined with respect to evidence of analgesia in cattle during pain states.