RESUMEN
INTRODUCTION: Pain and disability management are crucial for a speedy recovery. Combining analgesics with different mechanisms of action provides greater pain relief with lower doses, promoting efficient multimodal analgesia. This study evaluated the efficacy and safety between two fixed-dose combinations (FDC): etoricoxib/tramadol compared to paracetamol/tramadol for the management of acute low back pain (LBP) in a 7-day treatment. METHODS: We conducted a phase IIIb, prospective, randomized, and multicenter study in patients with acute LBP treated with etoricoxib 90 mg/tramadol 50 mg (one packet of granules diluted in 100 ml of water, once a day [QD], for 7 days) or paracetamol 975 mg/tramadol 112.5 mg (one tablet of 325 mg/37.5 mg, three times a day [TID], for 7 days) to assess the efficacy (in terms of pain and disability improvement) and safety. RESULTS: One hundred and twenty-four patients were randomized to receive either etoricoxib/tramadol QD (n = 61) or paracetamol/tramadol TID (n = 63). From the magnitude of change in pain evaluations, differences were observed between the treatment groups at 3 [p = 0.054, CI 95% - 0.648 (- 0.010 to 1.306)] and 5 days (p = 0.041). The proportion of patients with a 30% reduction in Visual Analogue Scale (VAS) score was statistically significant when comparing the treatment groups on the third day of follow-up [p = 0.008, CI 95% 0.241 (0.061-0.421)]. An improvement in LBP's disability to perform activities of daily routine (Oswestry and Roland-Morris questionnaires) was observed in both treatment groups. A total of 79 adverse events (AEs) (38 [48.1%] with etoricoxib/tramadol and 41 [51.9%] with paracetamol/tramadol) were reported. The most frequent AEs were nausea (17.7%) and dizziness (16.4%). CONCLUSIONS: The results show the clinical benefits of etoricoxib/tramadol FDC, such as the sparing effect of tramadol dose per day, early therapeutic response rate compared with paracetamol/tramadol; which translates into faster pain relief, better adherence, less tramadol drug dependency, and a reduction of related AEs incidence. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT04968158.