Use of opioids in patients with cancer with hepatic impairment—a systematic review

Opioids are recommended for moderate-to-severe cancer pain; however, in patients with cancer, impaired hepatic function can affect opioid metabolism. The aim of this systematic review was to evaluate the evidence for the use of opioids in patients with cancer with hepatic impairment.A systematic review was conducted and the following databases searched: AMED (-2021), MEDLINE (-2021), EMBASECLASSIC + EMBASE (-2021) and Cochrane Central Register of Controlled Trials (-2021). Eligible studies met the following criteria: patients with cancer-related pain, taking an opioid (as defined by the WHO Guidelines for the pharmacological and radiotherapeutic management of cancer pain in adults and adolescents); >18 years of age; patients with hepatic impairment defined using recognised or study-defined definitions; clinical outcome hepatic impairment related; and primary studies. All eligible studies were appraised using the Grading of Recommendations Assessment, Development and Evaluation system.Three studies (n=95) were eligible but heterogeneity meant meta-analysis was not possible. Each individual study focused on only one each of oxycodone±hydrocotarnine, oxycodone/naloxone and morphine. No recommendations could be formulated on the preferred opioid in patients with hepatic impairment.Morphine is the preferred opioid in hepatic impairment owing to clinical experience and pharmacokinetics. This review, however, found little clinical evidence to support this. Dose adjustments of morphine and the oxycodone formulations reviewed remain necessary in the absence of quality evidence. Overall, the quality of existing evidence on opioid treatments in cancer pain and hepatic impairment is low and there remains a need for high-quality clinical studies examining this.