Study Evaluating Dexketoprofen Trometamol/Tramadol Hydrochloride Analgesic Efficacy in Acute Low Back Pain

Inclusion Criteria

• Properly executed written informed consent.
• Male or female patients aged 18 years to 65 years.
• Patients with acute low back reporting pain of at least moderate intensity at Screening (NRS score ≥ 5). The onset of the current acute low back pain episode is within 48 hours prior to Screening.
• Patients with or without radiculopathy will be included, excluding those with neurological signs, according to the Quebec Task Force classification.
• Naïve patients to any low back pain or patients with previous history of low back pain experiencing a new episode, preceded by a period of at least 2 months without any low back pain prior to Screening.
• Patients free from analgesic (as per exclusion criterion 14) due to previously administered pain killer (immediate or slow release formulations), according to physician's judgment.
• Females participating in the study must be either:
• Females of non childbearing potential, defined as any woman who had undergone surgical sterilization (documented hysterectomy, bilateral salpingectomy, or bilateral oophorectomy) or is more than 2 years post menopausal (defined as no menses for 12 months);
• Females of childbearing potential (following menarche until menopause unless permanently sterile) provided that they have a negative pregnancy test at Screening and are routinely using an effective method of birth control resulting in a low failure rate (ie, combined hormonal contraception, intrauterine device, condoms in combination with a spermicidal cream, male partner sterilization (vasectomy), bilateral tubal occlusion or total sexual abstinence) during the study treatment.
• Mentally competent and able to understand and give written informed consent prior to Screening.
• Compliant to undergo all visits and procedures scheduled in the Study.

Exclusion Criteria

• Patients who are judged by the Investigator not to be suitable candidates for the study treatments and the Rescue Medication (RM) based on their medical history, physical examination, Concomitant Medication (CM) and concurrent systemic diseases.
• Clinically significant abnormalities in the vital signs as per Investigator's judgment.
• Patients with acute low back pain and radiation to limb with presence of neurologic signs (focal weakness, asymmetry of reflexes, sensory loss in a dermatome, or loss of bowel, bladder, or sexual function) according to Quebec Task Force Classification.
• History of hypersensitivity to the study treatments, RM or to any other nonsteroidal anti-inflammatory drugs (NSAIDs), or opioids.
• Known photoallergic or phototoxic reactions during treatment with ketoprofen or fibrates.
• History of peptic ulcer, gastrointestinal disorders when taking NSAIDs, gastrointestinal bleeding, or other active bleeding.
• History of allergy (eg, precipitate attacks of asthma, bronchospasm, acute rhinitis, or cause nasal polyps, urticaria or angioneurotic oedema) to the study treatments, RM or to any other NSAIDs, or opioids.
• Anamnestic mild to severe renal dysfunction, mild to severe hepatic dysfunction, as per Investigator's judgment.
• Patients with chronic dyspepsia.
• Patients with severe heart failure [Class III and Class IV of New York Heart Association (NYHA) Classification].
• History of hemorrhagic diathesis and other coagulation disorders.
• History of or current epilepsy or convulsions.
• Patients with Crohn's disease or ulcerative colitis.
• Patients receiving monoamine oxidase (MAO) inhibitors (a minimum of 14 days of washout must elapse prior to the Screening).
• Treatment with topical preparations/medications within 4 hours prior to Screening, anesthetics and muscle relaxants within 8 hours prior to Screening, short-acting analgesics (eg, paracetamol) within 4 hours prior to Screening, other analgesics within 5 half-lives prior to Screening or use of an opioid within the 14 days preceding Screening.
• Treatment with high doses of salicylates (≥3 g/day),