Clinical Research Directory

Inclusion Criteria: 1. Among patients with histologically or cytologically confirmed malignancy, patients with expected survival time of several months or less due to a progressive disease without additional anticancer treatment. 2. Patients with refractory cancer pain, which cases of requesting 4 or more breakthrough analgesics or increase of baseline analgesics (average pain score ≥ 4 or Personalized pain goal) in spite of 120 mg/day or more of intravenous Morphine Equivalent Daily Dose 3. Hospitalized patients with intravascular access during at least 5 days 4. Age 18 or older 5. Signed and dated informed consent of document indicating that the patient (or legally acceptable representative) has been informed about all pertinent aspects of the trial prior to enrollment Exclusion Criteria: 1. Patients who were treated with ketamine for pain control within 6 months 2. Patients who have been treated with radiotherapy within 4 weeks or plan to intervention for pain control during study period 3. Cancer pain cannot be excluded the Opioid induced hyperalgesia 4. Concomitant severe medical, surgical, or disease or problems which were contraindicated to application of Ketamine or have possibilities of unexpected medical problems caused be the Ketamine * confirmed or assumed central nervous system lesion which lead to increased intracranial pressure * Arrhythmia (supra-ventricular tachycardia, ventricular arrhythmia (frequent premature ventricular contraction, bigeminy, Ventricular tachycardia) * history of hemorrhagic stroke or seizure within 3 months