[A case of hepatic encephalopathy induced by adverse effect of morphine sulfate]

A 63-year-old man with liver cirrhosis and hepatocellular carcinoma presented with abrupt encephalopathy with markedly elevated blood ammonia levels. He was found lying down in front of the hospital 2 days after treatment of right hypochondrial pain with sustained-release oral morphine sulfate. He tended to be constipated before receiving morphine sulfate. The excess production of ammonia due to his constitutional constipation exacerbated by the use of oral morphine was thought to be the causal association with transient hepatic encephalopathy. He regained consciousness by receiving aminoleban intravenously and anticonstipating suppository. We realized that much care should be taken to avoid such opioid-related constipation at the time of pain management for quality of life improvement in patients with cancer pain.