Study of PHN131 in Patients After Surgery

• Primary Efficacy Endpoint: Pain assessment calculated as the area under the curve of VAS pain intensity scores through 48 hours.

• Secondary Efficacy Endpoints:

• Consumption of diclofenac (Day 1-2) via Intramuscular Injection (IM injection).
• Time from the end of operation to the first IM injection diclofenac dose
• Brief Pain Inventory (BPI).
• Patient satisfaction.

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
• Clinical lab values twice the upper limit of normal (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, Intrauterine Device (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 Cyclooxygenase-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 more than 5 times per week.
• Use of any long-acting opioid medication within 3 days of surgery or any opioid medication within 24 hours of surgery.
• Current painful physical condition or concurrent surgery requires analgesic treatment in the postoperative period.
• Contraindication to epinephrine or any of the pain-control agents planned for postoperative use.
• Administration of an investigational drug within the longer of 30 days or 5 elimination half-lives of such investigational drug prior to study drug administration.
• Any psychiatric disorder, psychological, medical, or laboratory condition that may interfere with study assessments or compliance.
• Significant medical conditions or laboratory results that may indicate an increased vulnerability to study drugs and procedures, and thus expose the subject to an unreasonable risk as a result of participating in this clinical trial.
• Any clinically significant event or condition uncovered during surgery.
• History of abuse illicit drugs, prescription medicines or alcohol within the past 2 years.
• Known history of anti-HIV antibody positive .
• Failure to pass drug and alcohol screen.