Optimizing Intravenous Patient-Controlled Analgesia for Cancer Pain: A Randomized Controlled Trial on Adjusted Background Infusion Rates

PURPOSE Patient-controlled analgesia (PCA) has been considered for managing cancer pain; however, limited research has been conducted on optimizing continuous infusion rates with PCA. This study aimed to evaluate the efficacy and safety of a method that optimizes background infusion (BI) alongside PCA for titrating intravenous (IV) morphine in managing cancer-related pain. METHODS Forty-four patients with solid tumors who could not manage pain with oral or transdermal opioid analgesics were randomly assigned in a 1:1 ratio to receive IV morphine through PCA or the conventional method. In the PCA group, the BI rate was automatically adjusted on the basis of the frequency and interval of bolus button presses; contrastingly, BI rate in the conventional group was adjusted at the discretion of the medical staff. The primary outcome was the daily number of patient complaints of breakthrough pain (numeric rating scale ≥4). RESULTS The PCA group reported a significant decrease in breakthrough pain complaints at 24 hours (median, 0 v 3 times/d; P = .012) and a lower proportion of nonresponders at 24 hours (21% v 55%; P = .048) compared with the conventional group. The total daily IV dose of morphine increased in the PCA group and exhibited a significant difference between two groups within 48 hours (median, 76.80 v 44.42 mg/d; P = .036). No uncontrolled opioid-related adverse effects were observed in either group. CONCLUSION PCA, with an optimized BI rate, facilitated faster titration of IV morphine than the conventional method, achieving tolerable and rapid pain relief.