Extended‐release injectable naltrexone for opioid use disorder: a systematic review

Aims

To review systematically the published literature on extended‐release naltrexone (XR‐NTX, Vivitrol^®), marketed as a once‐per‐month injection product to treat opioid use disorder. We addressed the following questions: (1) how successful is induction on XR‐NTX; (2) what are adherence rates to XR‐NTX; and (3) does XR‐NTX decrease opioid use? Factors associated with these outcomes as well as overdose rates were examined.

Methods

We searched PubMed and used Google Scholar for forward citation searches of peer‐reviewed papers from January 2006 to June 2017. Studies that included individuals seeking treatment for opioid use disorder who were offered XR‐NTX were included.

Results

We identified and included 34 studies. Pooled estimates showed that XR‐NTX induction success was lower in studies that included individuals that required opioid detoxification [62.6%, 95% confidence interval (CI) = 54.5–70.0%] compared with studies that included individuals already detoxified from opioids (85.0%, 95% CI = 78.0–90.1%); 44.2% (95% CI = 33.1–55.9%) of individuals took all scheduled injections of XR‐NTX, which were usually six or fewer. Adherence was higher in prospective investigational studies (i.e. studies conducted in a research context according to a study protocol) compared to retrospective studies of medical records taken from routine care (6‐month rates: 46.7%, 95% CI = 34.5–59.2% versus 10.5%, 95% CI = 4.6–22.4%, respectively). Compared with referral to treatment, XR‐NTX reduced opioid use in adults under criminal justice supervision and when administered to inmates before release. XR‐NTX reduced opioid use compared with placebo in Russian adults, but this effect was confounded by differential retention between study groups. XR‐NTX showed similar efficacy to buprenorphine when randomization occurred after detoxification, but was inferior to buprenorphine when randomization occurred prior to detoxification.

Conclusions

Many individuals intending to start extended‐release naltrexone (XR‐NTX) do not and most who do start XR‐NTX discontinue treatment prematurely, two factors that limit its clinical utility significantly. XR‐NTX appears to decrease opioid use but there are few experimental demonstrations of this effect.     

Influenza outbreak control practices and the effectiveness of interventions in long‐term care facilities: a systematic review

Background

Evaluation of influenza control measures frequently focuses on the efficacy of chemoprophylaxis and vaccination, while the effectiveness of non-pharmaceutical interventions (NPI) receives less emphasis. While influenza control measures are frequently reported for individual outbreaks, there have been few efforts to characterize the real-world effectiveness of these interventions across outbreaks.

Objectives

To characterize influenza case and outbreak definitions and control measures reported by long-term care facilities (LTCFs) of elderly adults and estimate the reduction in influenza-like illness (ILI) attack rates due to chemoprophylaxis and NPI.

Methods

We conducted a literature search in PubMed including English-language studies reporting influenza outbreaks among elderly individuals in LTCFs. A Bayesian hierarchical logistic regression model estimated the effects of control measures on ILI attack rates.

Results

Of 654 articles identified in the literature review, 37 articles describing 60 influenza outbreaks met the inclusion criteria. Individuals in facilities where chemoprophylaxis was used were significantly less likely to develop influenza A or B than those in facilities with no interventions [odds ratio (OR) 0·48, 95% CI: 0·28, 0·84]. Considered by drug class, adamantanes significantly reduced infection risk (OR 0·22, 95% CI: 0·12, 0·42), while neuraminidase inhibitors did not show a significant effect. Although NPI showed no significant effect, the results suggest that personal protective equipment may produce modest protective effects.

Conclusions

Our results indicate pharmaceutical control measures have the clearest reported protective effect in LTCFs. Non-pharmaceutical approaches may be useful; however, most data were from observational studies and standardized reporting or well-conducted clinical trials of NPI are needed to more precisely measure these effects.