Stop and go strategy for opioid switching requires flexibility

Opioid-induced Neurotoxicity in Patients with Cancer Pain

OPINION STATEMENT

Opioid-induced neurotoxicity (OINT) is a neuropsychiatric syndrome observed with opioid therapy. The mechanism of OINT is thought to be multifactorial, and many risk factors may facilitate its development. If symptoms of OINT are seen, the prescriber should consider hydration, discontinuation of the offending opioid drug, or switching of opioid medication, or the use of some adjuvants. Multiple factors like inter- and intraindividual differences in opioid pharmacology may influence the accuracy of dose calculations for opioid switching. Experience and clinical judgment in a specialistic palliative care setting should be used and individual patient characteristics considered when applying any conversion table.

A better interpretation of data regarding the opioid switching to methadone

In a recent study methadone has been reported more effective witha 3-day switch (3DS) was more effective than the stop and go strategy (SAG). Many shorcomings, however, are of concerns. The poor selection fo patients with low level of pain intensity, the incomprehensibile choice of of SAG or 3DS, and considerations reported in a previous controlled study with evident methodological limits, make their conclusion inaccurate. Controlled studies are fundamental in research. However, a pragmatic approach reflecting daily practice should be carefully taken into consideration. A more flexible use of SAG strategy and strict clinical observation to change doses according to the clinical response may provide the optimal treatment in patients receiving high doses of opioids.

Reply to "A better interpretation of data regarding the opioid switching to methadone"

In our article ?Methadone switching for refractory cancer pain' (BMC palliative care, 2022) we explore the efficacy, safety and economics of methadone in treatment of patients with refractory cancer pain in China. Professor Mercadante provided a better interpretation of data regarding the opioid switching to methadone in the Matters Arising. In this article, we answered the questions in Mercadante et al.'s comments one by one.

Maddalena Opioid Switching Score in patients with cancer pain

ABSTRACT

Evaluation of opioid switching (OS) for cancer pain has not been properly assessed. The aim of this study was to assess an integrated score (Maddalena Opioid Switching Score) as a simple and repeatable tool to evaluate the outcomes of OS, facilitating the interpretation and comparison of studies, and information exchange among researchers. The integrated score took into account pain intensity, intensity of opioid-related symptoms, and cognitive function by using an author's formula. Physical and psychological symptoms were evaluated by the Edmonton Symptom Assessment Scale and Patient Global Impression (PGI) by the minimal clinically important difference. One hundred six patients were analyzed. Ninety-five patients were switched successfully, and 11 patients underwent a further OS and/or an alternative procedure. The Maddalena Opioid Switching Score significantly decreased after OS and was highly correlated to PGI of improvement ( P < 0.0005). In patients with unsuccessful OS, no significant changes in the Maddalena Opioid Switching Score and PGI were observed. A significant reduction in Edmonton Symptom Assessment Scale items intensity was observed after OS. The Maddalena Opioid Switching Score resulted to be a sensitive instrument for measuring the clinical improvement produced by OS.

Conversion ratios for opioid switching: a pragmatic study

BACKGROUND

The final conversion ratios among opioids used for successful switching are unknown. The aim of this study was to determine the initial and final conversion ratios used for a successful opioid switching in cancer patients, and eventual associated factors.

METHODS

Ninety-five patients who were successfully switched were evaluated. The following data were collected: age, gender, Karnofsky performance score, primary cancer, cognitive function, the presence of neuropathic, and incident pain. Opioids, route of administration, and their doses expressed in oral morphine equivalents used before OS were recorded as well as opioids use for starting opioid switching, and at time of stabilization. Physical and psychological symptoms were routinely evaluated by Edmonton Symptom Assessment Scale.

RESULTS

No statistical changes were observed between the initial conversion ratios and those achieved at time of stabilization for all the sequences of opioid switching. When considering patients switched to methadone, there was no association between factors taken into considerations.

CONCLUSION

Opioid switching is a highly effective and safe technique, improving analgesia and reducing the opioid-related symptom burden. The final conversion ratios were not different from those used for starting opioid switching. Patients receiving higher doses of opioids should be carefully monitored for individual and unexpected responses in an experienced palliative care unit, particularly those switched to methadone. Future studies should provide data regarding the profile of patients with difficult pain to be hospitalized.

Methadone rotation for cancer patients with refractory pain in a palliative care unit: an observational study

BACKGROUND

Methadone has been reported to be as effective as morphine for cancer pain management. It is commonly used as an alternative opioid in case of insufficient relief.

OBJECTIVE

Our aim was to assess efficacy and tolerance of opioid rotation to methadone for refractory cancer pain management in palliative care unit (PCU) inpatients.

METHODS

All the patients undergoing opioid rotation to methadone from 2008 to 2011 in two PCUs (Lyon and Nice, France) were included. Pain assessments were undertaken on day 0 (D0), day 3 (D3), day 7 (D7), and day 14 (D14) using a visual analogue scale (VAS; 0-10) and the Douleur Neuropathique 4 (DN4) scale for neuropathic pain. Patients reported pain relief using a 4-point Likert scale (1=no relief; 4=important relief ).

RESULTS

Nineteen patients (7 females) with a median age of 55 (Q1-Q3; 44-58) underwent methadone rotation. The most common type of cancer was gastrointestinal. Seventeen patients had a diagnosis of mixed pain syndromes. Morphine equivalent daily dose (MEDD) prior to switching was 480 mg (Q1-Q3; 100-1021), and at least two nonmethadone opioid rotations had already been done for 13 patients. Between D0 and D7, the VAS score decreased by 4 points (p<0.001). The DN4 score became negative on D7 for 11 of 17 patients (65%). On D7, 16 of 18 patients (89%) expressed moderate to greater than moderate pain relief. Methadone was discontinued in one patient on D7 because it was deemed ineffective and for 8 patients, who were unable to take oral drugs, it was discontinued after D14.

CONCLUSION

Our results suggest that methadone is effective and well tolerated for refractory cancer pain.