Aubrun F, et al. - In this single centre prospective study, researchers investigated the impacts of four single nucleotide polymorphism (SNP) [opioid receptor mu1 (OPRM1), ATP-binding cassette subfamily B, member 1 (ABCB1) ex-21 and ex-26, catechol-o-methyltransferase (COMT)] in candidate genes involved in morphine pharmacodynamics and pharmacokinetics on morphine dose requirements and adverse events in the postoperative period among white adults scheduled for major orthopaedic surgery (spine, hip and knee) under general anaesthesia. Receiving opioids for chronic pain, nonopioid drugs within 2 days prior to surgery, pregnancy, renal insufficiency, sleep apnoea obstruction syndrome, morbid obesity, severe hepatic impairment, cognitive dysfunction were the main exclusion criteria. Findings showed no major association between SNP of OPRM1, ABCB1, COMT and morphine requirement, pain level or adverse effects in the postoperative period.