Background: Limiting harm from postoperative pain treatment is important. However, long-term follow-up from acute pain trials are rare. The aim of the study was to provide long-term follow-up data regarding harm from the “Paracetamol and Ibuprofen in Combination” (PANSAID) trial. Methods: In this preplanned long-term follow-up study from the PANSAID trial, we used data from Danish national health registries (the Danish National Patient Registry and the Danish Civil Registration System) in addition to the 90-day follow-up in the original trial. The primary outcome was 1-year proportion of patients with one or more serious adverse events. Results: One-year follow-up was complete for 551 patients (99%). We found three additional patients with one or more serious adverse events in the 1-year follow-up compared with the 90-day follow-up. The relative risk of having one or more serious adverse event when randomized to ibuprofen compared with paracetamol was 1.40 (95% CI: 0.84-2.33, P =.20). Conclusion: We found no statistically significant difference in 1-year serious adverse events between patients randomized to ibuprofen compared with paracetamol in patients having planned primary total hip arthroplasty. There were few additional events from the 90-day follow-up to the 1-year follow-up.