Patient-Controlled Analgesia Offers Superior Pain Management

BARCELONA — Intravenous patient-controlled administration of hydromorphone offers better pain control and higher patient satisfaction compared with conventional oral morphine in managing severe cancer pain, according to new research presented here at the European Society for Medical Oncology (ESMO) Congress.

The US National Comprehensive Cancer Network (NCCN) guidelines recommend maintaining analgesia for persistent cancer pain with conventional oral extended-release morphine around the clock as a background dose, supplemented with immediate-release morphine as a rescue dose for breakthrough pain.

However, few studies have compared continuous analgesic administration to patient-controlled dosing. There is limited evidence supporting the NCCN’s assertion that “although the oral route is most common, other routes may be considered to maximize patient comfort.”

Rongbo Lin, MD, Fujian Cancer Hospital, Fuzhou, China, and colleagues conducted a phase 3 randomized trial to investigate hydromorphone titration using intravenous patient-controlled analgesia.

The multicenter study conducted in 48 research centers in China involved 1364 patients with malignant solid tumors and persistent, severe cancer-related pain (numeric rating scale [NRS] score of ≥7 at rest). Participants were stratified based on whether they had received opioid analgesics for more than 7 consecutive days in the past 30 days and were divided into three groups, each receiving opioid analgesics through different methods over a 24-hour period.

One group (A1) received intravenous patient-controlled hydromorphone with bolus-only rescue doses, the second (A2) received a continuous patient-controlled infusion with bolus rescue doses, and the third group (A3) received conventional oral morphine.

“Intravenous patient-controlled administration of hydromorphone, with or without continuous infusion, provided superior pain control and patient satisfaction compared to conventional oral morphine” Lin told Medscape Medical News. Additionally, intravenous patient-controlled hydromorphone with bolus-only administration was non-inferior to continuous infusion for pain control, while requiring less morphine. This non-inferiority was observed in opioid-naive patients (those who had not received opioid analgesics for 7 consecutive days in the previous 30 days), but not in opioid-tolerant patients.

Moreover, grade 1 and 2 opioid-related adverse events — including constipation, nausea, vomiting, dizziness, and sedation — were significantly more frequent in the oral morphine group compared with the intravenous hydromorphone groups.

“Two important WHO pain relief principles are oral administration and administration on time,” explained Lin. “However, our research shows that for patients with severe cancer pain, the intravenous administration mode may be superior to oral administration, with less morphine consumption, higher patient satisfaction with pain control, and fewer side effects.” 

Lin’s research also found that the curative effects of group A1 and group A2 were similar. Group A1 used less morphine than group A2, and the patient satisfaction was almost the same with fewer side effects. 

“In the future, this is likely to change the mode of administration supported by the WHO principles,” Lin said. “In the future, better methods such as nasal sprays can be developed to facilitate patient pain relief, reduce morphine consumption, and reduce the occurrence of side effects”.

“Pain is a common symptom in cancer patients, and one question is how we administer analgesics to maximize symptom control and achieve proper titration for optimal pain relief,” Jayne Wood, MD, consultant in palliative medicine at the Royal Marsden Hospital, London, United Kingdom, told Medscape Medical News. “I typically administer continuous infusions subcutaneously, so it’s interesting to hear that bolus-only dosing is effective. It makes me reconsider how our pain team approaches patient management.”

The study was independently supported. Lin and Wood declared no conflicts of interest related to the study. 

Moheb Costandi is a freelance writer based in London.