Efficacy and Safety of Ultra-low Dose Methadone as Adjuvant Analgesic in Cancer Patients With Pain

A Double Blind Randomized Clinical Trial to Investigate the Efficacy and Safety of Ultra-low Dose Methadone as Adjuvant Analgesic Therapy in Cancer Patients With Pain

The research hypothesis of this study is: In patients with moderate to severe cancer related pain, the addition of low dose methadone to an existing opioid significantly reduces pain severity compared to low doses morphine.

Inclusion Criteria:

• Patients diagnosed of cancer-related pain of more than 3 months duration
• Pain relief during the last week rated unsatisfactory by the patient
• Pain severity during the last week rated moderate (between 4 and 7/10)
• Analgesic therapy must have been stable for 7 days
• Able to understand English or French
• Willing and able to give written informed consent

Exclusion Criteria:

• Patients who are currently receiving or have received methadone as analgesic in the last 6 months
• Contraindication to receive methadone (allergy, QTc segment on the ECG>450msec, concurrent treatment with medication that could increase methadone's effects)
• Patients presenting with changes in their cancer status/treatment with potential effects on their pain severity, during the duration of the trial (eg: new metastasis, indication for radiotherapy)
• Patients whose life expectancy is shorter than 2 months
• Patients with cognitive impairment presenting with difficulties understanding the trial and completing the research questionnaires
• Pregnant or lactating women (women of childbearing potential must have negative pregnancy test)