Phase III clinical trial, multicentre, superiority, randomized, open, parallel groups, with active control and use of postoperative oral medication (multiple doses of medication).

The main objective is to evaluate the effectiveness and safety of the association in relation to the isolated use of medicines.

Inclusion Criteria:

• Men or women aged 18 years or older;
• Be able to sign the ICF approved by the IEC and to perform and understand all the study procedures and instructions;
• Show post-anesthesia recovery with a score greater than or equal to 8 on the modified Aldrete and Kroulik Scale;
• Experience pain intensity according to the visual analogue scale (VAS) of 3.0 to 10 cm (moderate to severe pain) immediately after surgery;
• Have an elective open abdominal-pelvic surgery scheduled, not due to malignant neoplasm, to be performed within 4 weeks of screening;
• Estimated hospital stay for at least 48 hours after the procedure.

Exclusion Criteria:

• Surgical complications during participant enrollment in the research;
• Surgery with indication for treatment of confirmed or suspected malignant neoplasm;
• Chronic use of any non-steroidal anti-inflammatory drugs;
• Suspected paralytic ileus or intestinal obstruction;
• Inability to use oral drugs postoperatively;
• Videolaparoscopic surgery;
• History of chronic and current use of opioids or other analgesics;
• Use of concomitant modalities of intravenous or neuraxial analgesia (spinal and epidural) with placement of an epidural catheter for use in the postoperative period, or regional blockade, where the expected duration of analgesia administered intravenously or neuroaxially is maintained after 24 hours of the surgical procedure or randomization, whichever occurs first;
• Use of immunosuppressive therapy in the last 24 hours prior to surgery;
• Participants with uncontrollable vomiting present in the postoperative period;
• Abusive user of alcohol or illicit drugs;
• Use of drugs with potential interaction with the study drugs;
• Allergy, hypersensitivity, or known contraindication to the use of ingredients of the study drug;
• Psychiatric or social disorders that prevent the appropriate compliance with the protocol;
• Demonstrate inability to understand and perform current pain assessments in the study;
• Women who are pregnant, breastfeeding, planning to become pregnant, or who have a positive urine pregnancy test.
• Participants who test positive for COVID-19 (upon presentation of the test report at the time of screening or prior to randomization);
• Participation in another clinical trial within less than one year (unless the participation is warranted by the principal investigator);
• Presence of decompensated diabetes mellitus;
• History of decompensated obstructive or restrictive respiratory disease;
• Current symptoms or past history of gastrointestinal bleeding;
• History of blood dyscrasia or chronic disease of any nature that contraindicates the participant's participation at the investigator's discretion;
• Inability to understand and perform the pain assessments during the study;
• Hypersensitivity or contraindication to the use of ingredients of the study drugs;
• Grade III obesity (BMI above 40);
• Presence of one or more flu-like symptoms, such as: fever, cough, dyspnea, myalgia and fatigue, respiratory symptoms, gastrointestinal symptoms (such as diarrhea) within 14 days prior to the screening or randomization visit;
• Other serious comorbidities at the investigators' discretion (such as history of renal, hepatic, cardiac or other peptic ulcer);
• Any clinical condition that the investigator considers to pose a risk to the patient or interfere with study conduction.

The data may be shared with other parties upon reasonable request to the corresponding author of the publications and after agreement with the sponsor.