559 patients scheduled for total hip arthroplasty were randomized to one of four groups for postoperative analgesia: paracetamol 1000mg plus ibuprofen 400mg, paracetamol 500mg plus ibuprofen 200mg, paracetamol 1000mg alone, or ibuprofen 400mg alone. Each group received their allocated treatment every 6 hours for a total of 4 doses over 24 hours. Primary outcomes included morphine consumption over the first 24 hours and the incidence of serious adverse events. For 24-hour morphine consumption, the paracetamol 1000mg plus ibuprofen 400mg group demonstrated statistically significant lower morphine consumption compared to the other three groups, though clinical significance was only demonstrated relative to the paracetamol 1000mg alone group. No significant differences in the incidence of serious adverse events, or in the incidence of adverse events occurring within the first 24 hours of surgery, were observed between the four groups.