The efficacy and safety of intravenous chlorpromazine treatment for sleep disturbance in patients with incurable cancer, with oral administration difficulty: a 1-week, prospective observational study

Background: Sleep disturbance is a common psychiatric disorder in patients with cancer. However, many patients with incurable cancer have difficulty receiving oral administrations, which limits treatment options during disease progression. The aim of the present study was to assess the efficacy and safety of intravenous chlorpromazine treatment for sleep disturbances in patients with incurable cancer, with oral administration difficulty. Methods: A prospective observational study was conducted among 52 patients with incurable cancer, with oral administration difficulty received daily intravenous chlorpromazine treatment for sleep disturbance from 2018 to 2020 at a single-unit university hospital. St. Mary's Hospital Sleep Questionnaire (SMHSQ) compared sleep before and after intravenous chlorpromazine administration. The primary endpoint was the efficacy rate of sleep quality [defined as a score of >= 4 (range, 1-6)] 7 days after receiving chlorpromazine. Results: Beginning the day after receiving chlorpromazine, sleep quality significantly improved from a mean score of 1.6 +/- 0.7 to 4.3 +/- 1.2, and 80.8% [95% confidence interval (CI): 66.5-89.1%] and 69.2% (95% CI: 53.8-79.6%) of patients reported good sleep quality 3 and 7 days after receiving chlorpromazine, respectively. The patients reported increased total sleep time and fewer awakenings during sleep, and satisfaction with sleep and difficulty falling asleep improved. Some adverse events occurred [akathisia (n=2), dry mouth (n=2), and somnolence (n=3)]; all were Grade 1 (CTCAE ver5.0) and improved with chlorpromazine discontinuation. Systolic blood pressure and heart rate displayed no clinically problematic changes. Conclusions: Intravenous chlorpromazine has a high tolerability and effectively treats sleep disturbances in patients with incurable cancer with oral administration difficulties.