Volume 28, Issue 2 , Pages 102-103, August 2004
Olanzapine-induced delirium in a terminally ill cancer patient
Article Outline
To the Editor:
Olanzapine has been increasingly administered to terminally ill cancer patients for alleviation of multiple symptoms, such as delirium, nausea, and pain.1., 2., 3. Olanzapine has several psychopharmacological advantages over other medications, but can potentially cause delirium due to its higher affinity for anticholinergic receptors.4 However, to our best knowledge, only one case of delirium due to overdose of olanzapine has been reported in a patient who ingested 280 mg olanzapine.5 We describe here a terminally ill cancer patient who developed delirium after olanzapine was administered for control of nausea.
1. Case report
A 57-year-old man was referred to our palliative care consultation team due to intractable nausea. He had been diagnosed with lung cancer 8 months earlier, and underwent left inferior lobectomy of the lung followed by palliative chemotherapy. Due to disease progression, chemotherapy had been withdrawn 3 months before the consultation.
The patient was admitted to the respiratory unit due to poor pain control and progressive paralysis of both lower extremities from metastases to the thoracic vertebrae. Pain was controlled with radiation therapy and transdermal fentanyl 1200 μg/day. However, he still suffered from prolonged nausea, with episodic vomiting several times per day. He reported no clinical symptoms suggesting gastric or duodenal ulcer. On physical examination, his abdomen was soft and slightly distended without metallic bowel sounds. Abdominal radiograph disclosed no signs of intestinal obstruction, and CT scan revealed no specific lesions that could be responsible for nausea. Brain MRI showed a solitary small metastasis to the cortex without peripheral edema, and neurosurgeons disagreed that this was the chief cause of nausea. Laboratory findings identified no responsible metabolic etiology for the symptom. Thus, we attributed the etiology of nausea to multiple causes, including radiation therapy, opioids, and cachexia. Empiric antiemetic treatments, including bethanmethazone 4 mg/day, chlorpheniramine maleate 40 mg/day, metoclopramide 30 mg/day, prochlorperazine 15 mg/day, and famotidine 40 mg/day, failed. Therefore, we started oral olanzapine 2.5 mg (Day 1), and increased the dose to 5 mg on Day 5. The patient evaluated nausea as much improved, but on Day 7 he developed disturbed attention and concentration, disorientation, hallucination, somnolence, mild agitation, and insomnia. He was thus diagnosed with delirium. The score on the Delirium Rating Scale was 18. We stopped olanzapine on Day 8, and by Day 10 the delirious symptoms completely disappeared.
In this case, the time correlation between administration of olanzapine and occurrence of delirium was clear, indicating olanzapine was the primary cause of delirium. Clinicians should note that olanzapine can cause central anticholinergic side effects, including delirium, in seriously ill patients.
References
- . An open trial of olanzapine for the treatment of delirium in hospitalized cancer patients. Psychosomatics. 2002;43:175–182
- Olanzapine in the management of cancer pain. J Pain Symptom Manage. 2002;23:346–350
- A pilot exploration of the antiemetic activity of olanzapine for the relief of nausea in patients with advanced cancer and pain. J Pain Symptom Manage. 2002;23:526–532
- . Psychopharmacology of olanzapine: a review. Br J Psychiatry. 1999;174:52–58
- . A case of delirium due to olanzapine intoxication. Nervenarzt. 2003;74:1009–1011
PII: S0885-3924(04)00192-7
doi:10.1016/j.jpainsymman.2004.04.008
© 2004 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.
Volume 28, Issue 2 , Pages 102-103, August 2004
