There are about 53 million surgeries performed in the United States each year that require drugs for post-operative pain, and over half of these patients still experience inadequate pain relief. For this indication, the existing therapeutic classes are conventional centrally-acting mu opioid analgesics and non-steroidal anti-inflammatory drugs (NSAIDs). This market is dominated by parenteral formulations of opioids (e.g., morphine and fentanyl) for the intravenous, intramuscular, intrathecal, or epidural routes of administration, directly by hospital personnel or with patient-controlled analgesia (PCA) devices. On April 7, 2005 , the FDA announced a decision to require boxed warnings of potential cardiovascular risk for all COX-2 pain relievers and all NSAIDs, including older non-specific drugs. The new perception of risk by the medical community and regulatory agencies could sharply limit the future market potential of COX-2 inhibitors for the treatment of postoperative pain. The combined projected growth of the world market for treatment of surgical/trauma pain as well as obstetric and gynecological pain is projected to result in a market in excess of $5 billion by 2010.