Bupivacaine is a local anesthetic (pain medicine) that has an established safety profile. Collagen is a protein that is found in all mammals. The Xaracoll implant is a thin flat sponge made out of collagen that comes from cow tendons and contains bupivacaine. When inserted into a surgical site, the collagen breaks down and bupivacaine is released at the surgical site to provide postoperative pain control.