Morphine poisoning in a patient with malignant peritoneal mesothelioma: A case report

Our plain-English summary of Morphine poisoning in a patient with malignant peritoneal mesothelioma: A case report, by C. Zhao, J. Bai, S. Jia, et al (Experimental and Therapeutic Medicine, 2023).

The study

• Authors: C. Zhao, J. Bai, S. Jia, X. Zhang, D. Geng, D. Li, Y. Wang, S. Gao, F. Zhang, X. Liu
• Journal: Experimental and Therapeutic Medicine
• Published: 2023;25(5):197
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Pain is one of the most common symptoms of malignant peritoneal mesothelioma. Therefore, analgesia serves an indispensable role in the treatment of this condition. Morphine is a representative opioid, which is widely used in clinical practice; however, excessive or unreasonable application can cause poisoning. Few cases of morphine poisoning have been reported, and cases of morphine poisoning in patients with malignant peritoneal mesothelioma are even more rare. Here, we present a case of morphine poisoning in a patient with malignant peritoneal mesothelioma. The patient had a high abdominal tumor load, hepatorenal insufficiency, and was treated with a combination of morphine and the sedative benzodiazepine, eventually leading to morphine poisoning. Therefore, for cancer pain, omni-directional and whole-process management should be emphasized. In patients with hepatorenal insufficiency, those treated with morphine combined with benzodiazepines, or those with a high abdominal tumor load, attention should be paid to drug absorption, excretion and interaction, and the drug dose during administration should be reduced to avoid drug poisoning. If poisoning symptoms occur, timely measures should be taken to reduce poison absorption and increase poison excretion, and antagonists should be used to reverse the poisoning and reduce the damage caused.

Copyright: © Zhao et al.

In plain English

This was a case report about one 64-year-old man in China with malignant peritoneal mesothelioma who developed drug poisoning. The article does not discuss asbestos. For cancer pain the patient took sustained-release morphine tablets (30 to 60 mg every 12 hours) and, for poor sleep, occasional 1 mg estazolam tablets, a benzodiazepine sedative. The day after admission in October 2021 he was in a deep coma with constricted pupils. Blood testing found morphine at 3.5 mg/l (therapeutic level given as less than 1.0 mg/l) and a "diazepam component" of 6.6 mg/l (less than 2.0 mg/l). The doctors diagnosed respiratory failure caused by drug poisoning. They treated it with breathing support, gastric lavage, hemoperfusion, naloxone and flumazenil. He regained consciousness after about 6 hours and was discharged. The authors believed three factors contributed: the morphine and estazolam interacting, slowed bowel movement from heavy abdominal tumor load, and kidney insufficiency. They concluded that doctors should consider lower starting doses in such patients. They noted that the dose relationship between the two drugs could not be well discussed.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: case report (single patient), with a discussion of published literature on morphine and benzodiazepines
• Who was studied: One 64-year-old man with malignant peritoneal mesothelioma, admitted to the Fourth Hospital of Hebei Medical University, China, in October 2021
• Exposure: The article does not mention asbestos. The exposure studied was morphine hydrochloride sustained-release tablets (30 to 60 mg by mouth every 12 hours) taken together with estazolam tablets (1 mg by mouth as needed). He had earlier received 13 cycles of pemetrexed with platinum chemotherapy.
• Main results:
  • The day after admission the patient was in a deep coma with constricted pupils and a poor light reflex.
  • Blood gas analysis showed pH 7.290, PaCO2 59.4 mmHg and PaO2 33.5 mmHg.
  • Blood testing detected morphine at 3.5 mg/l (therapeutic level given as less than 1.0 mg/l) and a diazepam component at 6.6 mg/l (therapeutic level given as less than 2.0 mg/l).
  • The doctors diagnosed respiratory failure secondary to drug poisoning.
  • After treatment that included intravenous naloxone (0.4 mg) and flumazenil (0.3 mg), the patient's consciousness gradually recovered after about 6 hours.
  • The authors attributed the kidney insufficiency to the patient's serum creatinine of 136.1 µmol/l, which developed after his initial treatment.
  • First contributing factor proposed by the authors: morphine and estazolam both depress breathing and interact to enhance each other.
  • Second contributing factor proposed by the authors: high abdominal tumor burden slowed bowel movement and prolonged drug retention.
  • Third contributing factor proposed by the authors: kidney insufficiency may have slowed excretion of the drug.
• The authors' conclusion: The authors concluded that in patients with high abdominal tumor load, or with impaired liver or kidney function, doctors should pay attention to drug absorption, excretion and interactions. This applies especially when morphine is combined with benzodiazepines. They also concluded that doctors should consider lower initial doses to avoid poisoning.
• Limitations the authors state:
  • The authors said that because opioid doses vary widely and both drugs were within the safe range, the relationship between the doses of the opioid and estazolam could not be well discussed. They added that studies of the two drugs together are rarely reported.

Topics

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma.

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