Patient Controlled Subcutaneous Analgesia of Hydromorphone Versus Morphine to Treat Moderate and Severe Cancer Pain: A Randomized Double-Blind Controlled Trial

Context. Hydromorphone and morphine are the common drugs used for the treatment of moderate to severe cancer pain. Patient controlled subcutaneous analgesia (PCSA) is an effective technique to manage cancer pain. However, few studies have been conducted to show the efficacy and safety of PCSA of hydromorphone for the relief of cancer pain. Objectives. To explore the short-term efficacy and safety of PCSA elicited by hydromorphone for moderate to severe cancer pain. Methods. This was a single-center, randomized, active-controlled, double-blind trial (from April 2019 to August 2021). Sixty patients with moderate to severe cancer pain were randomized (1:1) to hydromorphone or morphine groups according to drug delivery by PCSA. The primary outcome was the pain intensity measured by a numerical rating scale (NRS) at 72 hours. Secondary outcomes included pain intensity measured by NRS at baseline, 15 minutes, 30 minutes, two hours, eight hours, 24 hours and 48 hours. The daily occurrence of breakthrough pain (BTP), impact of pain on quality of life measured by the brief pain inventory (BPI), the daily additional consumption of opioids and the incidence of adverse events were also recorded. Adverse events included nausea, vomiting, dizziness, constipation and respiratory depression. Results. A total of 57 patients (28 patients in the hydromorphone group and 29 patients in the morphine group) in the West China Hospital of Sichuan University were investigated. The mean (standard deviation [SD]) NRS in the two groups at baseline was 7.8 (1.7) in the hydromorphone group and 7.6 (1.7) in the morphine group, and at 72 hours were 3.4 (1.8) and 3.2 (1.5), respectively. The postoperative NRS in both groups was decreased significantly compared to baseline. The mean (SD) NRS at 30 minutes in the hydromorphone group was significantly lower than in the morphine group (3.9 [2.6] vs. 5.3 [2.1], P = 0.035). The daily occurrence of BTP in both groups at 48 hours and 72 hours decreased significantly compared to the corresponding baseline (P < 0.05), and there was no significant difference between the two groups. The total scores and sub-item scores of BPI at 24 hours and 72 hours after PCSA in both groups decreased significantly from baseline. A comparison of daily additional consumption of opioids between the two groups revealed no statistically significant difference. There were no significant differences in the incidences of nausea, vomiting, dizziness or constipation between the two groups (P > 0.05). Conclusion. This study found that the PCSA of both hydromorphone and morphine could effectively and safely relieve shortterm moderate to severe cancer pain. Of note, the PCSA of hydromorphone took effect more quickly than that of morphine. J Pain Symptom Manage 2024;67:50-58. (c) 2023 The Authors. Published by Elsevier Inc. on behalf of American Academy of Hospice and Palliative Medicine. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).