The management of opioid withdrawal

Molecular mechanisms of morphine tolerance and dependence; novel insights and future perspectives

Drug addiction is a devastating condition that poses a serious burden on the society. The use of some drugs like morphine for their tremendous analgesic properties is also accompanied with developing tolerance, dependence and the withdrawal symptoms. These symptoms are frequently severe enough to reinforce the person in recovery to start over the use of drug again and hinder the clinical use of drugs like morphine for chronic pain. Research into opioid receptors and related molecular pathways has seen resurgence in the wake of the growing opioid epidemic. The current study provides a comprehensive scientific exploration of the molecular mechanisms and underlying signalling in morphine tolerance and dependence. It also critically evaluates current therapeutic approaches, shedding light on their efficacy and limitations, and future prospects.

Opioid maintenance, weaning and detoxification techniques; where we have been, where we are now and what the future holds: an update

In 2017, the US Department of Health and Human Services declared a public health emergency on the opioid crisis. On average, 115 Americans die each day from an opioid overdose. The scope and breadth of this problem is continually evolving. In 2010, there was a shift in causes primarily due to the use of heroin, and currently the latest shift in opioid-related deaths involves a variety of synthetic opioids, particularly illicitly manufactured fentanyl. As the medical, sociological and political environments have drastically changed, especially in the USA, over the last 6 years with regard to opioid use and misuse, an updated review of the literature was necessary.

Opioid maintenance, weaning and detoxification techniques: where we have been, where we are now and what the future holds

SUMMARY Medically supervised opioid withdrawal is a complex and constantly evolving exercise in multimodal therapy that draws from the expertise of a variety of clinical specialties. Acute substitution and weaning has been performed utilizing opioid agonists, partial agonists (e.g., buprenorphine), mixed agonist/antagonists (e.g., Suboxone®), and α2 adrenergic agonists. While thousands of patients are being treated with these 'classic' opioid-withdrawal techniques, traditional treatment approaches are being challenged by the emergence of innovative techniques based on an understanding of the neurochemistry of addiction. Pharmacotherapy with controlled withdrawal is currently the most reliable method of opioid detoxification, but, as translational medicine continues to advance and genomic markers for opioid sensitivity and dependence are identified, the future shows great potential for growth and change.

Effect of potassium channel modulators on morphine withdrawal in mice

The present study was conducted to investigate the effect of potassium channel openers and blockers on morphine withdrawal syndrome. Mice were rendered dependent on morphine by subcutaneous injection of morphine; four hours later, withdrawal was induced by using an opioid antagonist, naloxone. Mice were observed for 30 minutes for the withdrawal signs ie, the characteristic jumping, hyperactivity, urination and diarrhea. ATP-dependent potassium (K⁺_ATP) channel modulators were injected intraperitoneally (i.p.) 30 minutes before the naloxone. It was found that a K⁺_ATP channel opener, minoxidil (12.5–50 mg/kg i.p.), suppressed the morphine withdrawal significantly. On the other hand, the K⁺_ATP channel blocker glibenclamide (12.5–50 mg/kg i.p.) caused a significant facilitation of the withdrawal. Glibenclamide was also found to abolish the minoxidil’s inhibitory effect on morphine withdrawal. The study concludes that K⁺_ATP channels play an important role in the genesis of morphine withdrawal and K⁺_ATP channel openers could be useful in the management of opioid withdrawal. As morphine opens K⁺_ATP channels in neurons, the channel openers possibly act by mimicking the effects of morphine on neuronal K⁺ currents.

The Edinburgh Addiction Cohort: recruitment and follow-up of a primary care based sample of injection drug users and non drug-injecting controls

BACKGROUND

Injection drug use is an important public health problem. Epidemiological understanding of this problem is incomplete as longitudinal studies in the general population are difficult to undertake. In particular little is known about early life risk factors for later drug injection or about the life course of injection once established including the influence of medical and social interventions.

METHODS

Individuals thought to be drug injectors were identified through a single primary medical care facility in Edinburgh between 1980 and 2006 and flagged with the General Registry Office. From October 2005 - October 2007, these cases were traced and invited to undergo interview assessment covering early life experience, substance use, health and social histories. Age and sex matched controls for confirmed cases (alive and dead) were later recruited through the same health facility. Controls for living cases completed the same structured interview schedule. Data were also collected on cases and controls through linkage to routine primary care records, death registrations, hospital contact statistics and police and prison records. All interviews were conducted with the knowledge and permission of the current GP.

RESULTS

The initial cohort size was 814. At start of follow up 227 had died. Of the remaining 587: 20 had no contact details and 5 had embarked from the UK; 40 declined participation; 38 did not respond to invitations; 14 were excluded by their GP on health or social grounds and 22 had their contact details withheld by administrative authorities. 448 were interviewed of whom 16 denied injection and were excluded. Of 191 dead cases with medical records 4 were excluded as their records contained no evidence of injection. 5 interviewed cases died before follow up was concluded though these individuals were counted as "live" cases. 1 control per case (dead and alive) was recruited. Linkage to Scottish Morbidity Records data (available from 1981 onwards) on general acute inpatient and day cases, mental health inpatient and day cases and cancer was provided by Information Services, NHS Scotland, for all cases interviewed and all dead cases. The Scottish Prison Service provided records for 198 (46%) of cases interviewed, 48 cases not interviewed and 34 (18%) of dead cases. For a sub-sample of 100 interviewees a search of the Lothian and Borders police database was made for official criminal records and 94 had criminal records. Data linkage for controls is ongoing.

CONCLUSIONS

Injecting drug users recruited from a community setting can be successfully followed-up through interviews and record linkage. Information from injecting cases is being analysed in terms of injecting patterns and possible influences on these. Comparisons between cases and controls will allow identification of possibly modifiable early life risk factors for drug injection and will also clarify the burden of disease associated with injection and the influence on this of different health and social interventions.

Post-treatment outcomes of buprenorphine detoxification in community settings: a systematic review

A systematic review was undertaken to examine studies of buprenorphine detoxification that has included post-treatment outcomes as well as more immediate aspects of progress. Studies were required to report details of buprenorphine withdrawal regime and post-treatment outcomes including abstinence rates. Only five studies met these criteria, with buprenorphine regimes lasting 3 days to several weeks, and with variable follow-up. Detoxification completion rates were 65-100%, but relatively few treatment completers were then drug free at their follow-up appointments. In subsequent prescribing, more patients had returned to opioid maintenance than complied with naltrexone. Our preliminary review indicates that buprenorphine is a suitable medication for the process of opiate detoxification but that this newer treatment option has not led to higher rates of abstinence following withdrawal. Further studies are required to more substantially examine abstinence outcomes, as well as characteristics which predict success.

Challenges in the development of prescription opioid abuse-deterrent formulations

Opioid analgesics remain the cornerstone of effective management for moderate-to-severe pain. In the face of persistent lack of access to opioids by patients with legitimate pain problems, the rate of prescription opioid abuse in the United States has escalated over the past 15 years. Abuse-deterrent opioid products can play a central role in optimizing the risk-benefit ratio of opioid analgesics--if these products can be developed cost-effectively without compromising efficacy or creating new safety issues for the target treatment population. The development of scientific methods for assessing prescription opioid abuse potential remains a critical and challenging step in determining whether a claim of abuse deterrence for a new opioid product is indeed valid and will thus be accepted by the medical, regulatory, and reimbursement communities. To explore this and other potential impediments to the development of prescription opioid abuse-deterrent formulations, a panel of experts on opioid abuse and diversion from academia, industry, and governmental agencies participated in a Tufts Health Care Institute-supported symposium held on October 27 and 28, 2005, in Boston, MA. This manuscript captures the main consensus opinions of those experts, and also information gleaned from a review of the relevant published literature, to identify major impediments to the development of opioid abuse-deterrent formulations and offer strategies that may accelerate their commercialization.

Buprenorphine and methadone: a comparison of patient completion rates during inpatient detoxification

Buprenorphine and methadone are both effective for the control of the acute signs and symptoms of opiate withdrawal, but it is not known if there are differences between these two medications for other important clinical outcomes. This observational, non-randomized study evaluated completion rates of patients over a 13-month period when buprenorphine replaced methadone as the medication used for short-term inpatient opiate detoxification. Of the 644 patients in the study, the 303 treated with buprenorphine were more likely to complete detoxification than the 341 treated with methadone (89% vs. 78%; P < .001). Improvement in completion rates coincided with the introduction of buprenorphine. We conclude that as compared to methadone, buprenorphine is associated with greater rates of completion of inpatient detoxification.

Less Pain, More Gain

Research indicates that persons addicted to opiates are likely to relapse following treatment or are at risk of terminating treatment early. The withdrawal experience may be one factor underlying early treatment discharge and several medications, including buprenorphine-naloxone, have been used to reduce withdrawal symptoms during detoxification. This retrospective study sought to determine whether patients who received buprenorphine-naloxone were retained in treatment longer than those who did not receive the medication. Data were collected on 170 patients admitted to the detoxification unit who either received (n = 85) or did not receive (n = 85) the medication. Differences in lengths of stay were found between the groups, thus warranting future research on the usefulness of buprenorphine-naloxone during detoxification and subsequent treatment. The importance of detoxification as an initial phase of treatment in relation to patient retention is discussed.

Short-term outcomes of five heroin detoxification methods in the Australian NEPOD Project

This study included 380 participants in five heroin detoxification trials whose data were pooled to enable direct comparison of five detoxification methods in the Australian National Evaluation of Pharmacotherapies for Opioid Dependence (NEPOD). Rapid detoxification achieved similar initial abstinence rates with either anaesthesia or sedation (average 59%), which were higher than was achieved by inpatient detoxification using clonidine plus other symptomatic medications (24%), which in turn was higher than outpatient detoxification using either buprenorphine (12%) or clonidine plus other symptomatic medications (4%). Older participants and those using more illicit drugs were more likely to achieve abstinence. Entry rates into ongoing postdetoxification treatment were as follows: buprenorphine outpatient (65%), sedation (63%), anaesthesia (42%), symptomatic outpatient (27%), and symptomatic inpatient (12%). Postdetoxification treatment with buprenorphine or methadone was preferred over naltrexone. Participants with more previous detoxification attempts were more likely to enter postdetoxification treatment. Given that outpatient detoxification was more effective with buprenorphine than with symptomatic medications and that rapid detoxification was more effective than the symptomatic inpatient method, the roles of the symptomatic methods should be reconsidered.

Short-term outcomes after brief ambulatory opioid detoxification with buprenorphine in young heroin users

AIMS

This study examines the outcomes at 1, 3 and 6 months after a very brief outpatient detoxification with buprenorphine in 18-25-year-old heroin users.

DESIGN

Prospective follow-up study.

SETTING

Outpatient drug treatment clinic, providing brief detoxification in downtown Baltimore, Maryland, USA.

PARTICIPANTS

One hundred and twenty-three subjects between 18 and 25 years old; 56% male; 95% Caucasian; seeking detoxification; living in Baltimore City and five surrounding counties.

INTERVENTION

Detoxification with buprenorphine over 3 days. Follow-up at 1, 3 and 6 months.

MEASUREMENTS

Drug use history, the Addiction Severity Index at baseline and follow-up, urine drug screens, evaluation of the detoxification experience.

FINDINGS

By self-report, 37% of the total sample were not currently using heroin at 1 month, 32% at 3 months and 29% at 6 months, and 6.7%, 10.1% and 11.8% had an opioid negative urine test at 1, 3 and 6 months, respectively. There was a significant reduction from the baseline in mean Addiction Severity Index drug use composite score, as well as the mean number of days of heroin and cocaine use during past 30 days, that was sustained over the three follow-up points. Engagement in aftercare was generally poor.

CONCLUSIONS

The findings show a reduced frequency and intensity of drug use, suggesting a possible role for brief outpatient detoxification in reducing the severity of dependence for some younger heroin users who may not yet be ready to engage in long-term abstinence-oriented or opioid substitution treatments.

Alpha2-adrenergic agonists in opioid withdrawal

OBJECTIVES

This paper presents the main findings of a systematic (Cochrane) review of the effectiveness of alpha2-adrenergic agonists in managing opioid withdrawal.

DESIGN

The original systematic review included controlled trials that compared alpha2-adrenergic agonists with another form of treatment (or placebo) in participants who were primarily opioid-dependent.

MAIN FINDINGS

Ten studies compared a treatment regime based on an alpha2-adrenergic agonist with one based on reducing doses of methadone. Withdrawal intensity is similar to, or marginally greater with alpha2-adrenergic agonists, but signs and symptoms of withdrawal occur and resolve earlier in treatment. Participants stay in treatment longer with methadone. The likelihood of completing withdrawal is similar, or slightly less, with clonidine or lofexidine. Clonidine is associated with more adverse effects than reducing doses of methadone. Three studies compared the alpha2-adrenergic agonists, clonidine and lofexidine. Lofexidine does not reduce blood pressure to the same extent as clonidine, but is otherwise similar to clonidine.

CONCLUSIONS

Participants stay in treatment longer with methadone regimes, which may provide greater opportunity for psychosocial intervention. Methadone regimes may be preferable for withdrawal in outpatient settings where the risk of relapse to heroin use is high. The use of methadone may also facilitate transfer to maintenance treatment should completion of withdrawal become unlikely. For those who are well prepared for withdrawal and seeking earlier resolution of withdrawal symptoms, alpha2-adrenergic agonist treatment may be preferred. Clonidine and lofexidine appear equally effective for inpatient settings, but the lower incidence of hypotension makes lofexidine more suited to use in outpatient settings.