Impact of individualized pharmaceutical care on efficacy and safety of opioid-tolerant outpatients with cancer pain: a multicenter randomized controlled trial

Background: Managing cancer pain is a growing challenge. Individualized pharmaceutical care is particularly important for opioid-tolerant outpatients due to variation in terms of their knowledge about pain, treatment adherence, and risk of experiencing inadequate analgesia and severe adverse events. This study aimed to determine the influence of individualized pharmaceutical care on outcomes in opioid-tolerant outpatients with cancer pain. Methods: A multicenter, open-label, randomized, controlled study was carried out. Opioid-tolerant outpatients experiencing chronic cancer pain and receiving sustained-release opioids were randomly assigned to the intervention group and the control group with a 1:1 ratio. The intervention group received individualized pharmaceutical care, while the control group received conventional care during 4-week period.The primary endpoint was medication adherence on the intention-to-treat (ITT) population. Secondary outcomes included the patients' knowledge of cancer pain and pain medications, pain score, frequency of breakthrough pain, quality of life (QoL) which were assessed on the ITT population. Adverse events were evaluated according to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Event (CTCAE) version 4.0 on the per-protocol (PP) population. Results: A total of 118 patients were enrolled, and 102 patients (51 in each group) completed the 30-day follow-up from six oncology centers in China. The proportion of patients adhering to opioid medication increased to similar levels in the two groups during the 4 weeks (P=0.149). The intervention group had a significantly lower pain score at 4 weeks compared to the control group (P=0.015), and the proportion of participants without breakthrough pain was significantly higher at 4 weeks than at baseline in the intervention group (P=0.029), but not in the control group (P=0.322). The two groups did not differ significantly in terms of QoL or adverse events. Conclusions: Our results suggest that individualized pharmaceutical care can markedly reduce patient-related problems and significantly improve pain control in opioid-tolerant outpatients. These findings validate the recommendations to include clinical pharmacists in the management of cancer pain.