Initial dose of tapentadol and concomitant use of duloxetine are associated with delirium occurring after initiation of tapentadol therapy in cancer patients.

Objective: Tapentadol causes fewer gastrointestinal adverse events than other potent opioid analgesics because of its low affinity for opioid receptors; however, development of symptoms related to central nervous system disorders, including delirium, has not been well-studied. This study aimed to identify the factors that influence the development of delirium after initiation of tapentadol therapy in hospitalized patients with cancer.

Design: Retrospective study.

Setting/patients: Among 93 patients, for whom treatment using tapentadol was initiated between December 1, 2017, and November 30, 2019, at a single center in Japan, 86 met the inclusion criteria and were enrolled in this study.

Main Outcome Measures: Delirium occurring within 2 weeks of initiation of the tapentadol treatment was diagnosed by a physician or nurse. Patient background information was obtained, including data on age, sex, medical history, adverse events, starting dose of tapentadol, and concomitant medications.

Results: Age ≥ 67 years, male sex, somnolence after initiation of tapentadol therapy, dose of ≥300 mg/day at the beginning of tapentadol therapy, switching from potent opioids, and concomitant use of duloxetine were associated with delirium occurring after tapentadol therapy initiation.

Conclusions: Among the factors associated with the incidence of delirium after the initiation of tapentadol therapy, patients whose starting dose of tapentadol was 300 mg/day or higher and those receiving concomitant duloxetine, a serotonin-noradrenaline reuptake inhibitor, were at high risk of developing delirium. These findings will help healthcare providers, including pharmacists, in development of treatment plans for preventing delirium when initiating tapentadol therapy in patients with cancer.