Reduced-dose Olanzapine Effectively Manages Chemotherapy-Induced Nausea with Minimal Sedation

Chemotherapy-induced nausea and vomiting (CINV) are significant side effects that can severely impact cancer patients' quality of life and treatment adherence. Traditionally, higher doses of antiemetics like olanzapine, particularly 10 mg, have been used for controlling severe nausea, but these come with the risk of sedation and other adverse effects.

Recent research from Japan has explored the benefits of a lower 5 mg dose of olanzapine taken at home after chemotherapy. This approach aims to maintain the antiemetic efficacy while minimizing sedative side effects and reducing costs, making the treatment more accessible. A phase 3, double-blind, placebo-controlled trial involving 500 women with breast cancer receiving outpatient anthracycline plus cyclophosphamide chemotherapy revealed promising results. Patients who received olanzapine 5 mg showed a significant decrease in nausea and vomiting, with 58.1% achieving a complete response during the first five days post-chemotherapy compared to 35.5% in the placebo group.

Importantly, the study found that while some patients experienced drowsiness, the incidence of severe concentration impairment remained low, and no major adverse events or treatment-related deaths occurred. The timing of administration was carefully studied, with olanzapine given within five hours after chemotherapy and before dinner, effectively reducing sedation during hospital visits and transportation.

This evidence supports the potential of low-dose olanzapine as an effective, safer, and more affordable option for managing CINV, especially in outpatient settings. Although conducted on Japanese women with breast cancer, these findings could influence international antiemetic protocols and improve patient-centered care across diverse populations.

Source: https://medicalxpress.com/news/2025-07-dose-olanzapine-curb-chemo-nausea.html