Thus, if pain is present in a performing horse, its elimination should restore normal performance to that animal. Pain-relieving drugs include analgesics and anesthetics. The analgesics block pain, with various types matching the extent of pain. Through selective pain relief, the narcotic analgesics control pain. By acting on receptors in the brain and spinal cord, they produce analgesia while leaving other sensations intact.
Examples are phenylbutazone, ketoprofen, and flunixin meglumine.
Local anesthetics block an area. Here the effect is non-selective, and the animal loses sensation in the treated area. They can also render smooth, skeletal, and cardiac muscle inexcitable and unresponsive. In the process of blocking cells, local anesthetics interrupt the transmission of pain signals. Examples of these numbing pain relievers include procaine, lidocaine, and mepivacaine.