ABSTRACT
We reported a clinical case in which decreased concentration of hydromorphone citrate in subcutaneous infusion therapy led to the improvement of subcutaneous induration. A subcutaneous infusion therapy with hydromorphone citrate was initiated in a 60-year-old female pancreatic-cancer patient with back pain. A subcutaneous induration has emerged when the infused concentration of hydromorphone citrate was increased from 0.17% to 0.83%. After the reduction in its concentration (0.28%), that subcutaneous induration has improved. For the alleviation of nausea and sedation, administration of haloperidol and midazolam were added at day 61 and day 70, respectively, with keeping the low concentration (≤0.28%) of hydromorphone citrate. Under this condition, further occurrence of subcutaneous induration was not observed. As a result, we suggested that the concentration of hydromorphone citrate in subcutaneous infusion therapy determined the onset of subcutaneous induration.