A Study of Intramuscular Sebacoyl Dinalbuphine Ester for Post-Hemorrhoidectomy Pain Management

Inclusion Criteria: * Male or female \>= 20 years of age at Screening * Scheduled to electively undergo 2 or 3-column excisional hemorrhoidectomy * American Society of Anesthesiology Physical Class 1 - 3 * Adequate clinical lab values (values of potential clinical concern are detailed in Appendix) or, if abnormal, deemed not clinically significant per the Investigator. * Ability and willingness to provide informed consent, adhere to the study visit schedule and complete all study assessments and language specific questionnaires Exclusion Criteria: * Body weight less than 40 kg. * Concurrent fissurectomy. * Subject is pregnant or breastfeeding. Women of childbearing potential must have a negative urine pregnancy test at Baseline. * Women of childbearing potential disagree to use an acceptable method of contraception (e.g., hormonal contraceptives, IUD, barrier device or abstinence) throughout the study. * History of hypersensitivity or allergy to amide-type local anesthetics, opioid, or any ingredient of the medications administered in this study. * Subject has a resting respiratory rate less than 8 per minute and blood oxygen saturation less than 90 mmHg. * Use of any NSAIDs, selective COX-2 inhibitors, opioid, acetaminophen, selective serotonin reuptake inhibitors (SSRI), tricyclic antidepressants (TCA), gabapentin, or pregabalin within three days of surgery. * Chronic use of opioid medications for more than 14 days in the last 3 months, or non-opioid pain medications mor…