The goal of the present phase IIb clinical trial was to compare the safety and efficacy of the fixed-dose combination etoricoxib-tramadol 120mg/100mg tablet (once a day, for three days) versus naproxen 220mg tablet plus tramadol 50 mg capsule in patients with acute postoperative pain after impacted third molar extraction. The main research question was: Is the analgesic efficacy of etoricoxib-tramadol 120mg/100mg tablet non-inferior to naproxen 220 mg tablet + tramadol 50 mg capsule in a clinical model of moderate to severe acute pain? After informed consent, patients were randomly assigned to one of the two arms: test product (etoricoxib-tramadol 120mg/100mg tablet) or active comparator (naproxen 220mg tablet + tramadol 50 mg capsule). After surgery, patients were requested to start the treatment with study drugs (test product was administered once daily for three days; meanwhile reference drug was administered twice a day for three days).

Investigators compared the effects of both treatments on pain intensity at different time frames using the visual analogue scale. Furthermore, the safety of investigational drugs was assessed during the study.

Inclusion Criteria:

• Patients of both sexes aged from 18 to 40 years.
• Patients who agreed to participate in the study by signing the informed consent.
• Patients with indication for surgical extraction of impacted lower third molars according to the Pell and Gregory classification.
• Healthy subjects or with history of controlled chronic non-communicable diseases or that can be controlled prior to surgery, which, in the investigator's opinion, do not represent an additional risk for the patient.
• Patients who, at the investigator's discretion, meet personal and family conditions that allow them to properly comply with the activities described in the protocol and adherence to treatment.

Exclusion Criteria:

• Findings in the clinical history, vital signs, physical examination or laboratory studies suggesting abnormal conditions which represent a risk for subject's health at the investigator´s discretion.
• Hypersensitivity to any of the active ingredients and/or excipients of the investigational drugs.
• Patients with active peptic or gastroduodenal ulcer or diagnosis 30 days prior to signing the informed consent.
• Patients with history of allergic asthma reactions.
• Patients with severe hepatic dysfunction, classified as Child Pugh C or when being less, the investigator considers it an additional risk for patients.
• Patients with a creatinine clearance <30 mL/min.
• Patients with coagulation disorders.
• Patients with Systemic Lupus Erythematosus.
• Patients with congestive heart failure (NYHA class II-IV), ischemic heart disease, peripheral arterial disease, or cerebrovascular disease who have recently (3 months) undergone coronary artery bypass grafting or angioplasty procedures.
• Patients at high risk of acute cardiovascular events (intense smoking, hypertension or uncontrolled diabetes mellitus).
• Patients with a history of systemic neoplastic diseases or under treatment with chemotherapy.
• Patients with a history of illicit drug abuse or addiction to alcohol or tobacco.
• Patients with monoamine oxidase inhibitors (MAOIs) treatment or during the last 2 weeks prior to the study drug administration.
• Patients with opioid analgesics, neuromodulators, or long-acting NSAIDs therapy who, according to medical criteria, cannot carry out a withdrawal scheme for at least five half-lives prior to surgery.
• Patients with history of seizures or who are under treatment with medications that reduce the seizure threshold and who, according to medical criteria, cannot carry out a withdrawal scheme within 30 days prior to surgery.
• Positive pregnancy test or lactating women.
• Positive rapid urine drug test.