Dose-ranging Study for Postoperative Analgesia in Subjects Undergoing Primary Unilateral Inguinal Hernia Repair

Effective postoperative pain control is a critical element in patient recovery, as the majority of patients may experience significant pain, particularly in the first few days following surgery. Appropriate postoperative pain management contributes to improved healing, faster patient mobilization, shortened hospital stays, and reduced healthcare costs.

Inclusion criteria

• Males 18 years of age and older at the Screening Visit.
• Scheduled to undergo, elective, primary, unilateral, open-technique, tension-free (Lichtenstein-type technique with mesh) inguinal hernia repair under general anesthesia.
• American Society of Anesthesiology (ASA) Physical Class 1-3.
• Capable and willing to comply with all study visits and procedures and to provide written informed consent.
• Able to speak, read, and understand the language of the informed consent form, study questionnaires, and other instruments used for collecting subject-reported outcomes, in order to enable accurate and appropriate responses to pain scales and other required study assessments.

Exclusion criteria

• Use of any of the following medications within the times specified before surgery:

• Long-acting opioid medication within 3 days.
• Any opioid medication within 24 hours.
• Concurrent painful physical condition that may require analgesic treatment in the postoperative period for pain that is not strictly related to the hernia repair procedure and may confound the postoperative assessments (e.g., rheumatoid arthritis, neuropathic pain, concomitant vasectomy).
• Body weight less than 50 kilograms.
• History of hypersensitivity or idiosyncratic reaction to amide-type local anesthetics.
• Other contraindication to bupivacaine.
• Contraindication(s) to epinephrine, such as concurrent administration of monoamine oxidase (MAO) inhibitors or antidepressants of amitriptyline or imipramine types, conditions where the production or exacerbation of tachycardia could prove fatal (e.g., poorly controlled thyrotoxicosis or severe heart disease), or any other pathological conditions that might be aggravated by the effects of epinephrine.
• Contraindication to any of the pain control agents anticipated to be used postoperatively (i.e., acetaminophen or oxycodone).
• Administration of an investigational product within 30 days or 5 elimination half-lives of such investigational product, whichever is longer, prior to study drug administration, or planned administration of another investigational product or procedure during the subject's participation in this study.
• Suspected or known addiction to or abuse of illicit drug(s), prescription medicine(s), or alcohol within the past 2 years.
• Uncontrolled anxiety, schizophrenia, or other psychiatric disorder that, in the opinion of the Investigator, may interfere with study assessments or compliance.
• Current or historical evidence of any clinically significant condition that, in the opinion of the Investigator, may increase the risk of surgery, complicate the subject's postoperative course, or indicate an increased vulnerability to study drugs and procedures and expose the subject to an unreasonable risk as a result of participating in this clinical trial.

If during surgery the following criterion is met:

• Any clinically significant event or condition uncovered during the hernia repair surgery (e.g., excessive bleeding) that might render the subject medically unstable or complicate the subject's postoperative course.