Treatment with buprenorphine-naloxone hydrochloride (BP-NLX) or extended-release naltrexone hydrochloride (XR-NTX) may not be associated with pain induction or aggravation of mild to moderate chronic pain, according to study results published in The American Journal on Addictions.
In this 2-phase prospective randomized open-label study (Clinicaltrials.gov identifier NCT01717963) adult patients (n=143; age 18 to 60) with opioid dependence disorders were recruited from 5 Norwegian outpatient clinics between November 2012 and July 2015. Following inpatient opioid detoxification, participants were randomly assigned to receive BP-NLX (4 to 24 mg per day sublingually) or XR-NTX (380 mg every 4 weeks intramuscularly) for 12 weeks. The second phase was a 36-week open-treatment trial in which patients were given a choice to be treated with BP-NLX or XR-NTX. Pain was assessed every 4 weeks with the Norwegian Short-Form of the McGill Pain Questionnaire (NSF-MPQ), which consists of 3 components: descriptors involving affective and sensory subscales, current pain intensity (PPI; 0-5 scale), and a visual analog scale (VAS; 0-100).
At baseline (week 4), 81 and 55 patients reported having chronic pain and no pain, respectively. At 12 weeks, 105 participants remained in the study, with 52 and 53 reporting chronic pain and no pain, respectively. No increases in pain intensity (ie, mean affective or sensory pain and mean PPI) were reported by participants in either treatment group over the 12-week duration of the first phase or by participants reporting chronic pain.
In the second phase of the study, patients taking XR-NTX continued to report comparable levels of pain, including patients who had switched after 12 weeks from BP-NLX. At week 48, 58 participants reported having chronic pain and 54 reported no pain. No patients discontinued the study because of pain-related issues.
Women vs men reported greater affective symptoms (odds ratio [OR], 0.36; 95% CI, 0.17-0.78; P =.01). Participants who tested negative for hepatitis C had greater odds of having a low PPI vs a high to moderate PPI (OR, 2.37; 95% CI, 1.01-5.56; P =.048).
Study limitations include the use of a self-reported questionnaire and a lack of verification of medical history of pain.
“Overall, our present results challenge the perceived notion that an opioid antagonist, such as XR-NTX, is likely to aggravate long-standing pain in individuals with opioid dependencies,” noted the authors.
Latif Z-E-H, Solli KK, Opheim A, et al. No increased pain among opioid-dependent individuals treated with extended-release naltrexone or buprenorphine-naloxone: A 3-month randomized study and 9-month open-treatment follow-up study [published online January 31, 2019). Am J Addict. doi:10.1111/ajad.12859