Analgesic Efficacy and Safety of Spinal Oxycodone in Total Hip Arthroplasty: A Preliminary Study

Abstract

Aim: The aim of this study was to assess the analgesic efficacy and safety of 1 mg and 0.5 mg oxycodone administration in a spinal block procedure for a total hip arthroplasty (THA). Patients and methods: Forty–two THA patients aged 59–81 with American Society Anesthesiology (ASA) II–III were included. All patients received anesthesia using spinal blockade, with bupivacaine 0.5% spinal heavy 2.5 ml, with 0.5 ml oxycodone hydrochloride 1.0 mg (group A; n = 28) or 0.5 mg (group B; n = 14). During surgery, each patient was sedated with 2–4 mg/kg/h intravenous propofol infusion. They received 100 mg intravenous ketoprofen at the end of the surgery at 8 pm and 8 am, with recommended doses every 12 h thereafter. Subcutaneous morphine 5 mg was used as a rescue analgesic, and the time to morphine use was recorded. After surgery, pain intensity (at the moment of patient report) was assessed using an 11–point numerical rating scale (NRS). The incidence of adverse effects was monitored. Blood samples were taken for assays of serum oxycodone, noroxycodone and bupivacaine levels. Results: The time to rescue analgesia was 9.6 ± 5.6 h in group A and 7.3 ± 1.9 h in group B, and it did not differ between patient groups (P = 0.179). The mean NRS pain score was 4.5 in group A and 4.2 in group B. Three group A patients had detectable oxycodone levels: two < 7.1 ng/ml and in 1 spinal block induced anesthesia was unsuccessful and so underwent general anesthesia (this patient was excluded from the analysis). Four group B patients had single values < 5 ng/ml. Noroxycodone levels were in all patients undetectable, and bupivacaine levels were 70–300 ng/ml. Regarding adverse effects, one patient had hypotension, one had bradycardia, and one had pruritus. Conclusions: Oxycodone in spinal block prolongs analgesia period, does not cause serious adverse effects and seems to be safe and effective opioid for patients undergoing THA.