Safety profile of intravenous patient-controlled analgesia for breakthrough pain in cancer patients: a case series study

The WHO analgesic ladder supports medication choice according to pain intensity. The use of the analgesic ladder in an inverse way, has the advantage of using the same principles of the original ladder to treat crisis of pain in cancer patients. The purpose of this study is to describe the use of intravenous patient-controlled analgesia (IV-PCA) technique in patients admitted to an oncological Hospital. This is a case series study. Patients assigned to receive IV-PCA between March 2011 and May 2012 were selected for the study. Medical records were reviewed, patients stratified according to the Karnofsky Performance Score (KPS). The primary outcome was to verify if different IV-PCA opioid solutions could be equally effective providing pain relief. Secondary outcomes were the incidence of clinical side effects that can be associated to IV-PCA infusions. A total of 95 medical records were reviewed. Most patients used IV-PCA with morphine (42.1 %), fentanyl (42.1 %) or methadone (15.7 %) to treat exacerbation periods of cancer pain. IV-PCA used as supplementary therapy successfully improved pain control in 78.9 % of the patients, without any difference related to opioid solution. KPS < 40 was related to higher rate of pain relief, without any difference in side effects in this group of patients. The most common side effects were sedation (10.5 %) followed by constipation (9.4 %) and nausea (4.2 %). Morphine presented a higher risk than fentanyl for sedation. Analgesia-related delirium or respiratory depression were not reported in this case series study. IV-PCA provided timely, safe and useful analgesia for patients with severe breakthrough pain and may be useful to help titration of opioids, weaning to oral analgesia and to decide for interventional procedures.