Benefits and risks of off-label olanzapine use for symptom management in cancer patients-a case report.

ABSTRACT

BACKGROUND: Cancer patients often experience symptoms such as anorexia, anxiety and insomnia, which can impact their quality of life. Randomized placebo-controlled trials support prophylactic use of olanzapine for the prevention of nausea and vomiting due to moderate and high-emetic risk chemotherapy. In the setting of palliative care, olanzapine is increasingly utilized as an off-label treatment of symptoms including anorexia-cachexia, anxiety, and insomnia. The following case reports will highlight the potential benefits and risks of off-label olanzapine use for symptom management in cancer patients. CASE DESCRIPTION Patient 1 is a female in her 70s with stage IV infiltrating ductal carcinoma of the right breast was having trouble tolerating treatment with letrozole, palbociclib, and denosumab due to uncontrolled nausea resulting in weight loss. Her nausea was refractory to multiple anti-emetics. Low dose olanzapine (2.5 mg) prevented nausea and allowed her to tolerate treatment. Patient 2 is a male in his 50s with renal cell carcinoma, who was receiving treatment with cabozantinib, presented with uncontrolled pain improved with opioid rotation from oxycodone to morphine. He was also experiencing uncontrolled anxiety despite treatment with alprazolam. Alprazolam was weaned and replaced with olanzapine resulting in improvement of his symptoms. Patient 3 is a male in his 60s with pancreatic adenocarcinoma who presented with muscle weakness and fatigue resulting in discontinuation of gemcitabine plus cisplatin. He also had symptoms of depression, poor appetite, and sleep problems. He was prescribed short course of dexamethasone 4 mg by mouth twice daily and olanzapine 5 mg by mouth nightly to improve symptoms. One week after, he presented with confusion and workup revealed hyperammonia which was treated with lactulose, which led to the return of baseline mentation. CONCLUSIONS: Olanzapine antagonizes multiple receptors and has potential to treat a host of symptoms including nausea, anorexia, anxiety, and insomnia, but healthcare providers should be mindful of potential risks and unclear benefits for off-label indications. More research and funding are needed evaluating off-label use of olanzapine for palliation of symptoms in cancer patients who are often frail and susceptible to adverse events.