A Randomized Controlled Trial Evaluating the Analgesic Effect of the Combination of Methadone With Morphine for Cancer Related Pain

CONTEXT AND OBJECTIVES

Although opioids play an indispensable role in the management of cancer-related pain, inadequate pain relief still occurs. The primary objective of this study was to evaluate whether the combination of a low dose of methadone with morphine promotes a reduction in opioid consumption; the secondary objectives were if the association promotes lower pain intensity, and adverse effects (AEs).

MATERIALS AND METHODS

A sample if 41 patients with cancer-related pain in palliative setting were included. Patients were starting the third step of the analgesic ladder, and 1 group (n=21) achieve methadone (2.5 mg/12 h) in combination with morphine/methadone, and another group (n=20) received morphine alone. Both groups could use morphine (5 mg) as needed to maintain pain intensity <4, and adjuvant in stable dose. The following outcomes were evaluated: total morphine dose, pain intensity, and AEs.

RESULTS

There was no difference in the number of adjuvants, and the dose of morphine used. Pain intensity was significantly lower in the morphine/methadone group after 2 weeks, with no statistically significant difference at other timepoints. There was no difference between groups in the AEs.

CONCLUSION

Low dose of methadone in combination with morphine provided faster pain control as compared with morphine alone, and although this study was not powered to show differences in AEs, we did not notice a difference.

Oral Methadone for Patients With Neuropathic Pain Due to Neoplastic Brachial Plexopathy

INTRODUCTION

The brachial plexus nerves originate from the cervical (C5-C8) and first thoracic (T1) spinal nerves, and innervate muscles and skin of the chest, shoulder, arm and hand. Brachial plexus injuries can occur as a result of shoulder trauma and inflammation. Malignant tumors can also cause neoplastic brachial plexopathy (NBP), and refractory neuropathic pain is the most common symptom of NBP. Methadone is a synthetic opioid with high efficacy as an opioid-receptor agonist, and its inhibitory effects on N-methyl-D-aspartate (NMDA) may play a role in pain relief. However, there is a need to examine if oral methadone exhibits safety and efficacy against neuropathic pain due to NBP.

CASE PRESENTATIONS

NBP was diagnosed in 3 cases without brain or cervical spine metastasis. The clinical features of these patients were analyzed retrospectively. None of the cases had an indication for surgery because of advanced cancer and all had received radiation therapy that had an insufficient effect, prior to methadone treatment. All 3 patients had nociceptive and neuropathic pain. Methadone for refractory pain was initiated using the stop-and-go method. NRS pain scores decreased in all cases and there were no severe side effects.

DISCUSSION

For the purpose of pain relief, patients with NBP may receive surgery, radiation therapy and nerve block, but these are not always effective. Methadone was recently shown to be superior to fentanyl in treating neuropathic pain in patients with head-and-neck cancer in a RCT, and our findings suggest that methadone may also be effective for patients with NBP.

CONCLUSION

More studies are necessary, but results in 3 cases suggest that oral methadone may be a safe analgesic agent for patients with neuropathic pain due to NBP.

Methadone as a Coanalgesic for Palliative Care Cancer Patients

BACKGROUND

Methadone offers many advantages for treating cancer pain. However, its pharmacokinetic profile makes its use as a full-dose opioid challenging.

OBJECTIVES

To evaluate the efficacy and safety of low-dose methadone as an adjunct to opioids in the treatment of cancer pain in palliative care patients.

DESIGN

A cohort was followed retrospectively for up to 60 days after the initiation of methadone as a coanalgesic.

SETTING/SUBJECTS

Patients were eligible if they were prescribed methadone as a coanalgesic for cancer pain management and followed by the palliative care team.

MEASUREMENTS

The primary efficacy end point was reduction of pain intensity (11-point numerical rating scale). Variables associated with pain intensity reduction were explored using logistic regressions. Adverse events were collected throughout the follow-up.

RESULTS

Seventy-two of the 146 subjects (49%) qualified as significant responders (≥30% reduction in pain intensity). Median time to significant response was seven days, and pain intensity on the day of methadone initiation predicted the response to treatment. The most frequently reported adverse events were drowsiness, confusion, constipation, and nausea. As expected in a palliative care population, there was a substantial amount of missing data.

CONCLUSIONS

A significant reduction in pain can be seen rapidly after the addition of methadone as a coanalgesic, particularly among patients with high pain intensity. More studies are needed to corroborate the efficacy of methadone as an adjunct to opioids.

Practical considerations in opioid use for brain neoplasm

Neurologists are often on the front lines of diagnosis for primary and metastatic brain tumors. Patients with brain tumors typically have multiple comorbidities and pain generators beyond headache, necessitating opioid therapy. Opioid-based pain relief and safety in the medically ill patient are complex. While using the lowest-potency opioid with adjunct medications is always prudent, patients with brain tumors frequently require dose escalation. Opioid selection and use is based on the patient's respiratory and cardiac function as well as drug clearance capability. Specific opioid combinations, employing long-acting and short-acting drugs, have greater efficacy in specific patient profiles and make adverse drug reactions, toxicity, abuse, and diversion less likely.