Intra-subject variability in post-operative patient-controlled analgesia (PCA): is the patient equally satisfied with morphine, pethidine and fentanyl?

Abstract

Our previous study suggested that when compared between patients, morphine, pethidine and fentanyl were equally satisfactory for use in patient-controlled analgesia (PCA), although quantitative differences in their side-effect profiles were detectable. The present study evaluated whether individual patients could detect differences or express preferences for individual opioids when treated by PCA with all three in random sequence finishing with the first administered opioid. The main side effects were pruritus, nausea and vomiting. There were few differences in patients' responses to morphine, pethidine and fentanyl, or of satisfaction with these drugs, across patients, but individual patients' responses to the opioids could be highly variable. Some patients were able to tolerate all three opioids investigated, some were intolerant to all and some patients appeared to be sensitive to one or two of the opioids but show a preference for the remainder. These findings support the clinical practice of changing from one opioid to another (with good effect) in post-operative patients experiencing intolerable side-effects. The reasons for a patient responding differently to different opioids and even to the same opioid on separate occasions are not clear and appear inexplicable on the grounds of currently postulated receptor affinities or of physicochemical properties of the opioids studied. A plethora of factors will influence how an individual patient will respond to surgery and how he/she will recover. The physiological response to opioids is one variable which appears to be influenced by this complex set of factors and in turn will affect them. The findings of this study, like that of its predecessor, suggest that morphine, pethidine and fentanyl can be used successfully in PCA and that for some patients who are responding poorly, changing the opioid may be beneficial.

Evaluation of Quality in Patient-Controlled Analgesia Provided by an Acute Pain Service

“…One problem with the use of PCA is that, as several research and clinical reports indicate, patients using PCA rarely medicate themselves to complete relief [15,16]. Actually whether satisfied or not, experiencing high pain scores and inadequate pain relief goes against the concept Karcı/Taşdögen/Erkin/Ş ahinöz/Kara/Elar of PCA [15].…”

“…Actually whether satisfied or not, experiencing high pain scores and inadequate pain relief goes against the concept Karcı/Taşdögen/Erkin/Ş ahinöz/Kara/Elar of PCA [15]. Having an unlimited supply of opioids, having the opportunity to ask for more and experiencing pain seems unlikely.…”

“…We believed that as others have mentioned less than optimal analgesia can be observed with PCA simply because patients prefer the pain rather than side effects of the drug that have an influence on their daily activities. Consequently, side effects are considered as a reason for dissatisfaction and limitation of medications in different therapeutic approaches [4,13,15,[17][18][19]. However, it should be remembered that postoperative pain therapy could not be blamed for all the side effects during this period.…”

Acupuncture for analgesia in the emergency department: a multicentre, randomised, equivalence and non‐inferiority trial

“…However, for pharmacokinetic and other reasons, some opioids may be better in some patients (Woodhouse et al, 1999 Level II).…”

Safety of opioid patch initiation in Australian residential aged care

“…On an individual patient basis, one opioid may be better tolerated than another and a change to an alternative opioid may be beneficial if the patient is experiencing intolerable side effects (Woodhouse et al, 1999 Level II).…”