Combatting pain after orthopedic/trauma surgery- perioperative oral extended-release tapentadol vs. extended-release oxycodone/naloxone

BACKGROUND High post-operative pain scores after "minor" orthopedic/trauma surgery are in part attributed to inadequate prescription of opioid analgesics. Novel concepts aiming to achieve sufficient analgesia while minimizing opioid-related side effects by avoiding fluctuating plasma levels are based on perioperative oral administration of extended-release opioids beginning with the first dose pre-operatively. This is the first study to evaluate analgesic efficacy and side effect rates of extended-release tapentadol compared to oxycodone/naloxone following orthopedic/trauma surgery. METHODS This randomized, observer-blinded, active-controlled prospective clinical trial had 2 co-primary endpoints: (1) Analgesic efficacy: Mean pain level on a numeric rating scale (NRS) from 0 to 10 during exercise over 5 days. (2) Safety: Side effect sum score of the following events: Nausea, vomiting, constipation, sedation, vertigo, somnolence. The study was powered to detect superiority of tapentadol for at least one endpoint pending statistical proof of non-inferiority for both endpoints in a first step. RESULTS Two hundred sixty-six trauma patients were randomized to receive either tapentadol (n = 133) or oxycodone/naloxone (n = 133). Analgesic efficacy: Mean (±SD) daily pain levels in the first five post-operative days were 2.8 ± 1.3 in both groups. Mean maximum pain intensity during exercise in the first 24 h after surgery was 3.8 ± 1.9 (tapentadol) and 3.8 ± 2.1 (oxycodone/naloxone). Statistically tapentadol was non-inferior but not superior to oxycodone/naloxone. SAFETY Vomiting on day 1 occurred in 11%, constipation in 35% of the tapentadol patients and in 16% and 30% of the oxycodone/naloxone patients (p = 0.60 and 0.33), respectively. The incidence of sedation/ vertigo was <10%, that of somnolence <2% in both groups (p > 0.3, respectively). The sum score of side effect events was 51% in the tapentadol vs. 49% in the oxycodone/naloxone group; risk difference 3% [95% CI, -8 to 14%]; p = 0.6). Non-inferiority of tapentadol could not be concluded as the pre-defined non-inferiority margin was exceeded. CONCLUSIONS With both concepts, mean maximum pain intensity during exercise within the first 24 h after orthopedic/trauma surgery was reduced to a score of <4. This analgesic efficacy came at the cost of mainly gastro-intestinal side effects. Thus, we now use a prophylaxis against nausea and vomiting and pre-emptive laxatives as part of these concepts. TRIAL REGISTRATION https://eudract.ema.europa.eu (EudraCT- Nr. 2011-003238-15 ); October 24th, 2012.