The use of opioids in cancer patients with renal impairment-a systematic review

Opioids are recommended for moderate to severe cancer pain; however, in patients with cancer, impaired renal function can affect opioid metabolism. The aim of this systematic review was to evaluate the current evidence for the use of opioids in cancer patients with renal impairment. A systematic review was conducted and the following databases were searched: MEDLINE (1966 to 2015), EMBASE (1980 2015) and Cochrane Central Register of Controlled Trials (up to 2015). Eligible studies met the following criteria: patients with cancer pain taking an opioid (defined as per the WHO ladder); > 18 years; renal impairment (serum creatinine > normal range (study dependent), creatinine clearance (CrCl) or glomerular filtration rate (GFR) measurements < 90 ml/min, or as per the study definition); clinical outcome related to renal impairment. All eligible studies were appraised using the Grading of Recommendation Assessment, Development and Evaluations (GRADE) system. Eighteen studies (n = 2422) were eligible but heterogeneity meant meta-analysis was not possible. Morphine was examined in eight studies (n = 1418), oxycodone in two studies (n = 325), and fentanyl, alfentanil or sufentanil were discussed in six studies in total (n = 442). No recommendations could be formulated on the preferred opioid in patients with renal impairment. There is lack of consensus within the existing literature on the relationship between morphine, creatinine levels and morphine-related side effects. Based on the current evidence, morphine should be used with caution; however, more evidence is needed. Fentanyl, alfentanil and sufentanil are recommended in patients with renal impairment based on pharmacokinetics and clinical experience. However, the present systematic review found very little clinical evidence for this. Overall, the quality of the existing evidence on opioid treatment in cancer patients with renal impairment is low. There remains a need for high-quality clinical studies examining opioids in patients with renal impairment.