ABSTRACT
In Japan, there are not many reports of using hydromorphone for patients with renal failure and occurring neurotoxicity such as disturbance of consciousness. This report includes two cases of consciousness disorder such as delirium when hydromorphone was started or increased in patients with renal dysfunction. In the case 1, delirium appeared when hydromorphone dosage was increased from 2.4 mg to 3.6 mg intravenously for cancer pain. After reduction of dosage, consciousness disorder was improved. In the case 2, delirium also appeared when oral hydromorphone started at 2 mg for cough and dyspnea. After discontinuation of hydromorphone, the disturbance of consciousness was improved. In both cases, hydromorphone improved cancer pain, cough, and dyspnea, but it was difficult to continue hydromorphone due to adverse events, and opioid switching was required. Although there are reports of neurotoxicity caused associated with the use of high-dose, long-term hydromorphone in patients with renal failure, neurotoxicity may be shown even with small doses and short-term administration.