Buprenorphine and Methadone for Opioid-dependent Chronic Back Pain Patients

Chronic non-malignant pain (i.e. pain unrelated to cancer that persists beyond the usual course of disease or injury) is a major concern in the United States. Opioids are the most commonly prescribed medication to treat patients with chronic non-malignant pain. However, in one systematic review of chronic low back pain, the authors note that, although clinical trials suggest that opioids are effective for short-term use (≤ 16 weeks), the effectiveness of long-term opioids (> 16 weeks) for pain relief and improved physical functioning is less clear.

Five to 31 percent of chronic back pain patients prescribed long-term opioids show aberrant drug-taking behaviors. Many develop tolerance and withdrawal, 43% of these patients exhibit opioid addiction. Therefore, patients with chronic pain and a co-occurring opioid addiction present a clinical challenge. In such cases, referral to addiction experts is recommended, but specialized treatment is currently based on expert opinion and observational studies.

The expert recommendation is detoxification followed by treatment with methadone, buprenorphine, naltrexone, or non-opioid analgesics in conjunction with behavioral counseling. Discontinuing short-acting opioid medications increases pain and will make it difficult for these patients to abstain from opioids due to the severity of pain. However, continuing these opioid medications worsens their addiction and renders opioids ineffective in the treatment of pain. Research is needed to compare the various medication-assisted treatments.

Long-acting opioids (e.g., methadone, buprenorphine) are used to replace treatment with short-acting opioids (e.g., hydrocodone, oxycodone). Methadone is a full mu-opioid-receptor agonist that can be effective in treating pain. Two small studies suggest that treatment of patients with chronic pain and co-occurring substance use disorder with methadone and adjunctive pain management therapy is superior to non-opioid treatment protocols. Despite the demonstration that methadone can be effective as both an analgesic and for opioid addiction treatment, it possesses side effects (e.g, constipation) and serious adverse events (e.g, respiratory depression, risk of overdose) that limit its use, making physicians reluctant to prescribe methadone.

Buprenorphine, a partial opioid agonist, is an alternative to methadone for treatment of opioid addiction, has a safety profile superior to methadone, and possesses analgesic properties. For outpatient use, buprenorphine is combined with naloxone (BUP/NLX) to reduce the potential for abuse (i.e., IV administration). When given to those who abuse prescription opioids BUP/NLX possesses better treatment outcomes than those who abuse heroin. In one uncontrolled case series of 95 participants, Malinoff and his colleagues concluded that the effectiveness in the treatment of opioid dependence, in providing analgesia, and the low abuse liability make BUP/NLX a potentially useful treatment for patients with chronic pain and co-occurring opioid addiction. In a randomized controlled trial by Blondell et al. (2010), treatment with BUP/NLX was superior to the abstinence-oriented approach in regards to treatment retention in patients with chronic pain and co-existent opioid addiction. However, there has not been a randomized clinical trial comparing BUP/NLX with methadone maintenance in chronic pain patients with opioid addiction. Preliminary data suggest that both 6-months BUP/NLX and methadone treatment results analgesia, but methadone treatment results in better addiction outcomes. The present study is designed to determine the complexity of recovery outcomes (e.g., functioning, mental health) in chronic pain patients. Clinicians need evidence-based guidelines to more effectively manage patients who have both chronic pain and evidence of opioid misuse or addiction behaviors.

In this study, we plan to investigate whether patients treated with BUP/NLX and usual care will have improved clinical outcomes as those provided with methadone treatment and usual care. Specifically, we propose to give 63 patients BUP/NLX therapy for 6 months (experimental group) and 63 patients methadone therapy over 6 (active comparator). We hypothesize that patients given BUP/NLX treatment will have similar outcomes as those receiving methadone maintenance with respect to functioning, mental health, pain level, and treatment retention.