Risk to heroin users of polydrug use of pregabalin or gabapentin

Antihistamine-related deaths in England: Are the high safety profiles of antihistamines leading to their unsafe use?

AIMS

Antihistamines are routinely taken to control allergic reactions or sedation to induce sleep. There are, however, growing concerns regarding sedating antihistamine misuse. This research aims to evaluate deaths related to antihistamines in England occurring during 2000-2019.

METHODS

Cases reported to the National Programme on Substance Abuse Deaths from England occurring in 2000-2019 with antihistamine detections at postmortem were extracted for analysis.

RESULTS

In total, 1666 antihistamine postmortem detections were identified from 1537 cases. Sedating antihistamines available for purchase under pharmacist supervision but without need for a prescription (pharmacy-only medications) were present in a significant majority of cases (85.2%, P < .01). Despite an increasing trend for antihistamine-related deaths over time, the proportion of deaths where an antihistamine was implicated declined over the same period. Specific concerns with regards to the misuse of these pharmacy-only sedating antihistamines are raised with regards to the significant proportion of cases that were concluded as suicide (20.9%, P < .01), and the high prevalence of their use in combination with other central nervous system depressants (94.8% of cases).

CONCLUSION

This is the first report in over 40 years regarding antihistamine-related mortality from England. The rising trend in sedating antihistamine-related deaths may be contributed to by their increasing availability and the perceived negligible dangers associated with antihistamines, both from the general public and learned professionals. Awareness of the dangerous sedative properties that some antihistamines possess is, however, heightened in individuals deliberately seeking these effects. Urgent review of sedating antihistamines currently assigned under the pharmacy-only classification is needed to achieve antihistamine harm reduction.

New approved and emerging pharmacological approaches to alcohol use disorder: a review of clinical studies

introduction: The number of medications approved for AUD is small and they generally have limited efficacy. We need new pharmacotherapies for the management of AUD.Areas covered: In this review, the authors aim to synthesise literature for new approved and emerging pharmacotherapies for AUD. Recently approved medications include nalmefene, which was approved in Europe and Australia for the purposes of controlled drinking. Baclofen has also been approved in France but not in other countries. Off label medications including topiramate and gabapentin have received significant attention with multiple RCTs and meta-analyses and have widespread use in several countries including the USA. Several novel medications have emerged over the last decade but further work is required to determine their efficacy and safety for the widespread management of AUD.Expert opinion: Despite significant advances in our understanding of the neurobiological basis of factors that contribute to the development and maintenance of AUD, there have been few new AUD medications approved for almost 20 years. There are many challenges to the development and introduction of new pharmacotherapies for AUD. Strategies for improving the translational pipeline include drug repurposing and utilisation of human acute laboratory models.

Prevalence of and Factors Associated with Gabapentinoid Use and Misuse Among Texas Medicaid Recipients

BACKGROUND AND OBJECTIVES

Gabapentin and pregabalin have been considered relatively safe opioid-sparing adjuncts for pain management. However, rising prescribing trends, presence of gabapentinoids in opioid-related overdoses, and the growing body of evidence regarding gabapentinoid misuse and abuse, have caused gabapentinoids to emerge as a drug class of public health concern. This study aimed to assess the prevalence of, and factors associated with gabapentinoid use and misuse.

METHODS

This retrospective study of Texas Medicaid data from 1/1/2012 to 30/8/2016 included patients aged 18-63 years at index date, with ≥ 1 gabapentinoid prescription, and continuously enrolled 6 months pre-index and 12 months post-index. Gabapentinoid misuse was defined as ≥ 3 claims exceeding daily doses of 3600 mg for gabapentin and 600 mg for pregabalin. Age, gender, concurrent opioid use, neuropathic pain diagnoses and gabapentinoid type were independent variables. Descriptive and inferential statistics were used.

RESULTS

Of included subjects (N = 39,000), 0.2% (N = 81) met study criteria for gabapentinoid misuse. Overall, the majority (76.4%) of gabapentinoid users were aged 41-63 years with a mean ± SD age of 48.2 ± 10.7 years. Those patients meeting the study criteria for gabapentinoid misuse were significantly younger (45.1 ± 11.0 vs 48.2 ± 10.7, p = 0.0084). Majority of the study sample was female (68.1%). However, a significantly higher proportion of males met the study criteria for gabapentinoid misuse compared to females (0.3% vs 0.2%, p = 0.0079). Approximately one-half (51.9%) of the study sample had neuropathic pain, and gabapentinoid misuse was significantly higher in neuropathic pain patients compared to those without neuropathic pain (0.3% vs 0.1%, p = 0.0078). Over three-quarters (77.4%) of patients were using gabapentin; however, gabapentinoid misuse was significantly higher among pregabalin users (0.4% vs 0.2%, p = 0.0003). Approximately 20% (17.3%) of gabapentinoid users had ≥ 90 days of concurrent opioid use. However, there was no significant difference in gabapentinoid misuse among patients with concurrent opioid use compared to patients without (0.3% vs 0.2%, p = 0.1440). Factors significantly associated with misuse included: male sex (odds ratio [OR] 0.486; 95% confidence interval [CI] 0.313-0.756; p = 0.0013); neuropathic pain (OR 2.065; 95% CI 1.289-3.308; p = 0.0026); and pregabalin versus gabapentin use (OR 2.337, 95% CI 1.492-3.661; p = 0.0002). Concurrent opioid use was not significantly associated with gabapentinoid misuse (OR 1.542, 95% CI 0.920-2.586; p = 0.1006).

CONCLUSION

Prevalence of gabapentinoid misuse was low (0.2%) among Texas Medicaid recipients. Younger age, male gender, neuropathic pain diagnosis and pregabalin use were significantly associated with higher levels of gabapentinoid misuse.

Impact of the Opioid Epidemic on Drug Testing

BACKGROUND

This review provides a description of how the opioid epidemic has impacted drug testing.

METHODS

Four major service areas of drug testing were considered, including emergency response, routine clinical care, routine forensics, and death investigations.

RESULTS

Several factors that the opioid epidemic has impacted in drug testing are discussed, including specimens, breadth of compounds recommended for testing, time to result required for specific applications, analytical approaches, interpretive support requirements, and examples of published practice guidelines.

CONCLUSIONS

Both clinical and forensic laboratories have adapted practices and developed new testing approaches to respond to the opioid epidemic. Such changes are likely to continue evolving in parallel with changes in both prescription and nonprescription opioid availability and use patterns, as well as emerging populations that are affected by the "waves" of the opioid epidemic.

Clinical correlates and outcomes associated with pregabalin use among people prescribed opioids for chronic non-cancer pain: A five-year prospective cohort study

AIMS

Pregabalin has become widely used as an alternative to opioids in treating certain types of chronic non-cancer pain, but few studies have examined its clinical efficacy outside trials. We address this gap by examining the utilization, correlates and clinical outcomes of pregabalin use among an Australian community-based cohort of people prescribed opioids for chronic non-cancer pain.

METHODS

Through a five-year prospective cohort study (n = 1514) we examined associations between pregabalin use and pain severity and interference, mental health, opioid dose and past month use of ambulance and emergency department services. We used fixed-effects regression models to examine within-participant differences, and random-effects regression models to examine within- and between-participant differences in clinical outcomes.

RESULTS

In an analysis of cases with complete data over five-years (n = 896), the prevalence of pregabalin use ranged from 16% at cohort entry to 29% at 36- and 48-months, and 46% reported pregabalin use at any time during the five years. Pregabalin use was associated with greater pain severity and interference and greater use of high-risk opioid doses (>90 oral morphine equivalents/day). Pregabalin use was not associated with changes in mental health symptoms, ambulance or emergency department attendance in the fixed or random effects models.

CONCLUSIONS

Pregabalin use was common, but for most people use was not associated with clinically meaningful improvements in pain or functioning.

Gabapentinoid Abuse in France: Evidence on Health Consequences and New Points of Vigilance

Introduction: Gabapentinoid drugs (gabapentin and pregabalin) are widely used worldwide for epileptic and pain disorders. First signals of gabapentinoid abuse occurred in the last decade. This study aims to describe clinical characteristics of gabapentinoid use related disorders and health consequences in France. Materials and Methods: We designed a multisource investigation reviewing data reported to the French Addictovigilance Network (FAN) with pregabalin and gabapentin from 2010 to 2019. Information was obtained through the analysis of Spontaneous Reports (SRs) notified by health professionals and the pharmacoepidemiological surveys OSIAP (suspicious prescriptions forms indicators of potential abuse), OPPIDUM (observation of illicit drugs and misuse of psychotropic medications), DRAMES (death related to prescription drugs and other substances), and DTA (toxic deaths due to analgesics). Results: Over 2010-2019 period, were collected: (i) 265 SRs (258 pregabalin; 7 gabapentin); (ii) 816 forged prescription forms (805 pregabalin, 10 gabapentin, 1 involving both drugs); (iii) 145 cases of gabapentinoid use in people who use drugs (121 pregabalin; 24 gabapentin) and (iv) 31 cases of gabapentinoid-related deaths (25 pregabalin; 6 gabapentin). Risk factors of gabapentinoid abuse were opioid use disorders or psychiatric history, but cases of primary abuse in subjects without any substance abuse history were observed. Adverse outcomes concern almost exclusively pregabalin, with coma, dyspnea, convulsion, and conduction disorders. Treatment demands increased from 10.6% in 2018 to 23.1% in 2019, with pregabalin cited as the first substance leading to addictological care in the 2019 OPPIDUM survey. Gabapentinoid-related deaths increased over time. Pregabalin has become the first drug mentioned in forged prescriptions in 2019 (23.8% of OSIAP), while it ranked at the 15th position in 2017 (2.6%). Discussion: This study shows the importance of addictovigilance monitoring for gabapentinoids. Addictovigilance data helped to make visible the gabapentinoid-abuse related health harms (hospitalization for serious neurologic, psychiatric or cardiac effects, requests for addictological support and deaths) and to confirm the intrinsic abuse potential of pregabalin. These data highlight new points of vigilance considering observed primary abuse. At this point in France, the risk of abuse and related complications is very apparent with pregabalin. Still, it is identical to that observed elsewhere with gabapentin.

Current Evidence on Abuse and Misuse of Gabapentinoids

This review summarizes current evidence on the abuse and misuse of the gabapentinoids pregabalin and gabapentin. Pharmacovigilance studies, register-based studies, surveys, clinical toxicology studies, and forensic toxicology studies were identified and scrutinized with the goal to define the problem, identify risk factors, and discuss possible methods to reduce the potential for abuse and misuse. Studies found that gabapentinoids are abused and misused and that individuals with a history of psychiatric disorders or substance use disorder seem to be at high risk. Moreover, some evidence supports the notion that patients with opioid use disorders may be at an increased risk of abusing gabapentinoids. Available evidence also suggests that abuse and misuse are more frequent in users of pregabalin compared with users of gabapentin. Health professionals and prescribers should be aware of the risk for misuse of pregabalin and gabapentin, which eventually could lead to abuse, substance dependence, and intoxications. Prescribing to patients belonging to risk populations such as those with psychiatric disorders or substance use disorder should be avoided if possible and, if prescribed, signs of misuse and abuse should be monitored.

Association of Gabapentinoids With the Risk of Opioid-Related Adverse Events in Surgical Patients in the United States

IMPORTANCE

The use of gabapentinoids in multimodal postoperative analgesia is increasing; however, when coadministered with opioids, these drugs may potentiate central nervous system and respiratory depression.

OBJECTIVE

To evaluate the association between perioperative coadministration of gabapentinoids and opioids with inpatient opioid-related adverse events in surgical patients.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used propensity score trimming, stratification, and weighting of adults admitted for a major surgery between October 2007 and December 2017 who were treated with opioids on the day of surgery and included in the Premier Research database. Data analysis was conducted from February to April 2020.

EXPOSURE

Gabapentinoids (gabapentin or pregabalin) coadministered with opioids starting the day of surgery vs opioid therapy without gabapentinoids.

MAIN OUTCOMES AND MEASURES

Primary outcome was opioid overdose. Secondary outcomes included respiratory complications, unspecified adverse effects of opioid use, and a composite of these 3 outcomes. Patients were followed up for as long as 30 days from the day of surgery until deviation from the initial treatment regimen or discharge.

RESULTS

Gabapentinoids with opioids were administered to 892 484 of 5 547 667 eligible admissions (16.1%; mean [SD] age, 63.5 [11.8] years; 353 315 [39.6%] men). Among the 4 655 183 patients who received opioids only, the mean (SD) age was 63.7 (14.7) years, and 1 913 284 (41.1%) were men. Overall, 441 overdose events were identified, with absolute risks of 1.4 per 10 000 patients with gabapentinoid exposure and 0.7 per 10 000 patients receiving opioids only. Following propensity score trimming, the cohort included 737 383 patients exposed to gabapentinoids and 3 002 480 patients receiving opioids only. The primary analysis yielded the adjusted hazard ratio of 1.95 (95% CI, 1.49-2.55), and the number needed to treat for an additional overdose to occur was 16 914 patients (95% CI, 11 556-31 537 patients). Adjusted hazard ratios for secondary outcomes were 1.68 (95% CI, 1.59-1.78) for respiratory complications, 1.77 (95% CI, 1.61-1.93) for unspecified adverse effects of opioids, and 1.70 (95% CI, 1.62-1.79) for the composite outcome. The results were consistent across sensitivity analyses and subgroups identified by key clinical factors.

CONCLUSIONS AND RELEVANCE

In this real-world cohort study of patients who underwent major surgery, concomitant use of gabapentinoids with opioids was associated with increased risk of opioid overdose and other opioid-related adverse events; however, the absolute risk of adverse events was low.

Abuse and Misuse of Pregabalin and Gabapentin: A Systematic Review Update

BACKGROUND

A 2017 systematic review (SR) identified 59 studies examining gabapentinoid (pregabalin and gabapentin) misuse/abuse. Evidence of gabapentinoid misuse/abuse has since grown substantially.

OBJECTIVE

Update previous SR and describe new insights regarding gabapentinoid abuse.

METHODS

A SR of PubMed was conducted to identify studies published from 7/29/2016-8/31/2020. Four searches were performed using the following terms: "gabapentin [MeSH] OR pregabalin [MeSH] OR gabapentinoid" AND one of the following substance misuse/abuse-related terms: "substance-related disorders [MeSH]", "overdose", "abuse", or "misuse". Clinicaltrials.gov and the Cochrane Library database were searched to identify ongoing studies or similar SRs. Reference lists of included studies were reviewed to identify additional literature. All studies with novel data related to pregabalin and/or gabapentin abuse, misuse, or overdose conducted during the study period were included. Articles not written in English, review articles, and animal studies were excluded.

RESULTS

Fifty-five studies were included (29 [52.7%] from North America, 17 [30.9%] Europe, 6 [10.9%] Asia, and 3 [5.5%] Australia). Forty-six observational studies and 10 case reports/series were included (one manuscript included both). Twenty (36.4%) studied gabapentin only, 18 (32.7%) pregabalin only, and 17 (30.9%) both pregabalin/gabapentin. These studies corroborate findings from the previous SR that gabapentinoids are increasingly abused or misused to self-medicate, that gabapentinoids can produce desirable effects alone but are often used concomitantly with other drugs, and that opioid use disorder is the greatest risk factor for gabapentinoid abuse. While the original SR identified the largest studies having been published in Europe, this review identified several more generalisable US studies that have subsequently been conducted. The most concerning finding was increased evidence of associated patient harm, including increased hospital utilisation and opioid-related overdose mortality risk.

CONCLUSION

Evidence suggests that gabapentinoid misuse/abuse represents a growing trend that is causing significant patient harm. Prescribers should exercise appropriate caution with use in high-risk populations and monitor for signs of misuse or abuse.

Unintentional exposure to pregabalin in ≤6-year-old children: a nationwide French Poison Control Center study

INTRODUCTION

In France, pregabalin is widely prescribed in adults but still not approved for children. We aimed to investigate the incidence of pregabalin exposure in ≤6-year-old children, to describe the characteristics and outcome of ingestions involving pregabalin alone, and to estimate a clinically relevant toxic dose in this population.

METHODS

Retrospective analysis of pregabalin exposures in ≤6-year-old children, collected by the French Poison Control Centers in 2004-2019. The incidence was estimated using pregabalin prescription data from the Health Improvement Network database (the French version of THIN). The poison severity score (PSS) was used to grade severity.

RESULTS

We found 313 unintentional immediate-release pregabalin ingestions in ≤6-year-old children. The number of cases per 100,000 pregabalin-treated adults increased over time (p < 0.001). One hundred twenty-six cases involving pregabalin alone (age, 2 years [1.6-3.0] (median [25th-75th percentiles]); median ingested dose 6.4 mg/kg [3.6-10.9]) were analyzed. No child presented an underlying neurological/cardiac disease and/or took concomitant medications. Most of the children (77%) remained asymptomatic (PSS0) while 21% and 2% developed minor (PSS1) or moderate (PSS2) neurological symptoms, respectively. No severe complications/fatalities were reported. All symptomatic children recovered within 24 h. The ingested pregabalin dose was positively correlated with PSS (p < 0.0001). Using a ROC curve approach (area under the curve, 0.85; p < 0.001), ingestion of ≥19.4 mg/kg pregabalin was appropriate to recommend hospital referral (sensitivity, 39% [95% confidence interval (95% CI), 24-56], specificity, 100% [95% CI, 96-100], predictive positive value, 100% [95% CI, 64-100], and negative predictive value, 85% [95% CI, 82-89]). Symptomatic children who ingested <19.4 mg/kg pregabalin developed minor symptoms.

CONCLUSION

Despite increasing prescriptions in adults in France, unintentional pregabalin ingestions in ≤6-year-old children remain rare and cause minimal toxicity. Children with no underlying neurological/cardiac disease and concomitant medication ingesting <19.4 mg/kg immediate-release pregabalin alone can be safely observed at home.

Non-medical use of benzodiazepines and GABA analogues in Europe

AIMS

We investigated the prevalence of non-medical use (NMU) of benzodiazepines and GABA analogues in Europe.

METHODS

Data were collected using the online Non-Medical Use of Prescription Drugs (NMURx) survey from France, Germany, Italy, Spain and the UK.

RESULTS

The study included 55 223 eligible surveys which, after post-stratification weights were applied, represented approximately 260 million European adults. Lifetime NMU of benzodiazepines was highest in Spain (6.5%, 95% CI: 6.0-7.0) and lowest in Germany (1.7%, 1.5-2.0). Lifetime NMU of GABA analogues was highest in Germany (5.4%, 5.0-5.7) and lowest in France (2.2%, 1.9-2.5) and the UK (2.2%, 1.9-2.6) While no notable difference was observed for France or the UK, there was a higher prevalence of last 12-month NMU of benzodiazepines compared to GABA analogues in Italy (2.4 times higher) and Spain (3.0 times higher) and a higher prevalence of NMU of GABA analogues compared to benzodiazepines in Germany (2.6 times higher).

CONCLUSION

This study shows that there is variation in NMU of benzodiazepines and GABA analogues among countries. Of particular interest is the high incidence of GABA analogue NMU in Germany and benzodiazepine NMU in Spain. Further research to identify factors and motivations responsible for the higher prevalence observed are essential to inform public health policies in those countries.

A study of the reasons for prescribing and misuse of gabapentinoids in prison including their co-prescription with opioids and antidepressants

PURPOSE

Electronic medical case files of male prisoners in a category B prison in London were studied to establish a prevalence during an eight-month period of the use of and the reasons for prescribing gabapentinoids in prison and also to establish prescribing standards in prison and compliance with these. In addition, the prevalence of co-prescription of gabapentinoids with opioids and antidepressants, particularly tricyclic antidepressants such as amitriptyline, was also assessed in light of the increased risk of respiratory depression resulting in death when these drugs are used in combination. The paper aims to discuss these issues.

DESIGN/METHODOLOGY/APPROACH

A retrospective, SystmOne case-file based survey was undertaken searching by SNOMED CT supplemented by examination of free text, in a category B prison for males (Capacity 1,500 prisoners; Average turnover of prisoners up to 6,000 per year), to establish practice standards related to the prescription of Gabapentinoids in the prison and determine compliance with these.

FINDINGS

In total, 109 cases were identified of prisoners having been prescribed gabapentinoids, pregabalin in 66 cases (61 per cent) and gabapentin in 43 cases (39 per cent). In 36 cases (33 per cent) prescriptions were for unlicensed indications. This in fact represented 50 per cent of the cases where the indications were documented. In 51 cases (47 per cent) gabapentinoids were prescribed with an opioid substitute. In 14 cases (13 per cent), prescribed gabapentinoids were diverted to other prisoners.

PRACTICAL IMPLICATIONS

The initiation of gabapentinoids in prison should be avoided. For prisoners who are also receiving opioid substitutes or are abusing opiates, it may be unsafe to continue on gabapentinoids. Issues raised by this study are likely to apply to other prisons, secure forensic psychiatric facilities and indeed community mental health and primary care as well.

SOCIAL IMPLICATIONS

Risk of dependance on gabapentinoids including risk of mortality when taken with opioids and opioid substitutes.

ORIGINALITY/VALUE

This is an original study conducted at a category B prison in London.

Gabapentin-induced drug-seeking-like behavior: a potential role for the dopaminergic system

Drugs of abuse represent a growing public health crisis. Accumulating evidence indicates that gabapentin (GBP), a prescription drug, is prone to misuse, abuse, withdrawal, and dependence. Commonly, drugs of abuse modulate the dopaminergic system to induce addiction. In this study, we used the conditioned place preference (CPP) model to investigate the involvement of the dopamine 1 (D1) receptor on the reward and reinforcement behavior of GBP. Under a CPP paradigm, male BALB/c mice were intraperitoneally injected either saline or 100, 200, or 300 mg/kg of GBP and confined to the injection-paired chamber for 30 min. In the pre-conditioning phase, mice were conditioned for 3 days, and baseline data were collected. In the conditioning phase, mice were given once-daily alternating injections of either GBP or saline for 8 days and subsequently assessed in a post-conditioning test. Injections of 300 mg/kg of GBP significantly increased the time spent in the drug-paired chamber compared to the saline-paired chamber. However, lower doses of GBP (100 and 200 mg/kg) showed no effect. Pre-treatment with SKF-83566, a D1 receptor antagonist, attenuated GBP-induced CPP. Thus, for the first time, we show that GBP can induce CPP through a dopaminergic-dependent mechanism.

Not what the doctor ordered: Motivations for nonmedical prescription drug use among people who use illegal drugs

BACKGROUND

Nonmedical Prescription Drug Use (NMPDU) is common among people who use illegal drugs. NMPDU is particularly problematic among this population however, as medications such as benzodiazepines and gabapentinoids can potentiate the harmful effects of opioids. Despite these harms, there is some evidence that NMPDU can have harm reducing and therapeutic potential for some people who use illegal drugs. This study provides further evidence of the harm reducing motives for NMPDU among people who use illegal drugs in community and prison settings in Wales, UK.

METHODS

In depth, semi-structured interviews were conducted with 60 interviewees recruited from statutory and third sector drug treatment providers operating in five towns and cities in Wales, and from two Welsh prisons. Eligibility was based primarily on whether the person was currently (or previously) a user of illegal drugs and had recent experience of NMPDU.

RESULTS

NMPDU was found to be largely driven by insufficient access to certain prescription medications and treatment. In this context, NMPDU played an important role in alleviating legitimate medical concerns and overcoming logistical and regulatory barriers associated with Opioid Substitution Therapy. NMPDU also had everyday practicality and mitigated many of the everyday harms experienced by people who use drugs, including opioid withdrawal and stimulant comedowns.

CONCLUSION

Results suggest that NMPDU has the potential to mitigate a number of legitimate medical concerns in the absence of treatment. Finding nuanced ways of responding to patient need whilst reducing the potential for NMPDU are therefore needed, and harm reduction strategies that harness the knowledge and expertise of people who use drugs should be encouraged. Additional policy measures that attend to the inequities and social-structural factors that produce and maintain the need to consume prescription medications in ways that are not intended are also required.

Patterns and correlates of prescribed and non-prescribed pregabalin use among a sample of people who inject drugs in Australia

INTRODUCTION AND AIMS

Pregabalin is a gamma-aminobutyric acid analogue registered and subsidised for the treatment of neuropathic pain in Australia. Despite pre-clinical evidence of low abuse potential, there are increasing reports of extramedical use and overdose deaths involving pregabalin. This study aimed to describe patterns of pregabalin use among an Australian sample of people who inject drugs (PWID) and identify sociodemographic, substance use and mental/physical health correlates of prescribed and non-prescribed use.

DESIGN AND METHODS

Data were obtained from the 2018 Illicit Drug Reporting System, comprising a cross-sectional sample of 905 PWID recruited from Australian capital cities. Multinomial logistic regression was used to identify correlates of past 6-month prescribed and non-prescribed pregabalin use.

RESULTS

One-quarter (25%) of participants reported any past 6-month pregabalin use, with 10% reporting prescribed use and 15% non-prescribed use. Past 6-month use of prescribed benzodiazepines and non-prescribed pharmaceutical opioids were associated with both prescribed and non-prescribed pregabalin use compared to no recent pregabalin use. Pain/discomfort on the day of interview was significantly associated with prescribed pregabalin use. Recent use of non-prescribed benzodiazepines and illicit stimulants and past year non-fatal overdose were significantly associated with non-prescribed pregabalin use (compared to no recent pregabalin use).

DISCUSSION AND CONCLUSIONS

Pregabalin use was relatively common among an Australian sample of PWID. Benzodiazepine and pharmaceutical opioid use were positively correlated with both prescribed and non-prescribed pregabalin use, suggesting that education campaigns regarding the risks of harm associated with concomitant use of these substances are warranted (targeting both health professionals and consumers).

Pregabalin poisoning and rising recreational use: a retrospective observational series

AIMS

With rising use worldwide, pregabalin is increasingly implicated in poisoning deaths. We aimed to investigate the clinical effects and complications of pregabalin poisoning.

METHODS

This is a retrospective review of patients presenting with pregabalin poisoning to two tertiary toxicology units from 1 July 2014 to 30 June 2019. Patients were identified from prospective databases maintained by both units and data were extracted from these in addition to medical records.

RESULTS

There were 488 presentations in 413 patients (237 [57%] male) over the five-year period. The median age was 41 years (IQR 31-50 years). Deliberate self-poisonings accounted for 342 (70%) presentations, with 121 (25%) recreational exposures. Recreational exposures increased over the period from 2 (4%) in the first year to 54 (39%) presentations in the final year. The median dose of pregabalin was 1200 mg (IQR 600-3000 mg, range 75-16 800 mg). Co-ingestions occurred in 427 (88%) presentations, with sedating agents being co-ingested in 387 (79%)-most commonly opioids and benzodiazepines in 201 (41%) and 174 (36%) presentations respectively. Coma (GCS < 9) occurred in 89 (18%) cases, with 52 (11%) patients being intubated. Only one (0.2%) of these patients had not co-ingested a sedating agent. Hypotension occurred in 26 (5%) cases, all with co-ingestants. Seizures occurred in 11 (2%) cases, 3/59 (5%) in pregabalin-only overdoses. The median length of stay was 16.5 hours (IQR 10-25 hours).

CONCLUSIONS

Pregabalin overdose does not cause severe toxicity, but rather mild sedation and, uncommonly, seizures. Coma is common in the presence of sedating co-ingestants. Recreational use is increasing.

[Pregabalin and risk of addiction: A new care issue?]

PURPOSE

Pregabalin (PRG) is a gamma-aminobutyric acid (GABA) analogue used for treatment of epilepsy, neuropathic pain, generalised anxiety disorder and currently being studied for other indications. Supported by the results of case studies and a limited number of studies, there is an ongoing debate about the addictive potential of PRG. However, evidence is scarce and no definitive assessment on the potential for abuse and dependence to PRG is available. The objective of our study was to identify the number of cases of abuse or dependence to PRG published and to study potential risk factors of addiction to PRG.

METHODS

We have identified on PubMed and ScienceDirect published case studies of PRG abuse or dependence and analysed these cases on the basis of several clinical parameters.

RESULTS

A total of 118 cases of PRG abuse or dependence were identified, including 21 isolated cases (mean age 33 years, 67 % men). The mean daily dose of PRG was 2,9 g. Current or past polydrug abuse was present in the majority of cases. Psychiatric diagnoses, other than substance-related disorders, were reported in as many patients, and almost all patients experienced withdrawal symptoms when PRG was discontinued.

CONCLUSION

Current literature suggests an important and growing concern for the abuse of PRG. Male sex, psychiatric and/or addiction history, including opioid addiction, may be potential risk factors for the development of addictive behaviours associated with PRG.

Pregabalin and Its Involvement in Coronial Cases

Pregabalin is an anticonvulsant and analgesic designed to treat neuropathic pain and partial seizure disorders and has been available in Australia as a prescription medication since 2005. Studies have found high rates of polydrug use associated with pregabalin and it is reportedly used recreationally for its euphoric and relaxing effects as well as to self-manage opioid withdrawal symptoms. A robust analytical method for the analysis of pregabalin using protein precipitation and LC/MS/MS was developed, validated and employed in routine case work. In recent years a substantial increase in pregabalin detections in coronial case submissions had been noted. This study examines the case characteristics and outcomes of 332 coronial cases submitted to the laboratory and analyzed for pregabalin between 2015 and 2017. Pregabalin was identified in approximately 5% of all coronial cases submitted during this time. A high rate of concurrent drug use with pregabalin was evident with the predominant classes being opioids, benzodiazepines and anti-depressants. Post-mortem blood pregabalin concentrations ranged from <0.05 to 140 mg/kg (median 5.5 mg/kg); however, limited interpretation of levels could be achieved as the drug was rarely identified in the absence of other drugs. Cause of death (COD) was found to be drug related in 58% of all cases, with mixed drug toxicity specifically mentioned as related to COD in 40% of cases.

Use of promethazine, gabapentin and clonidine in combination with opioids or opioid agonist therapies among individuals attending a syringe service program

BACKGROUND

Clonidine, gabapentin, and promethazine are commonly used by people who use opioids, including heroin, raising concern for increased morbidity and mortality in a vulnerable population. We aimed to characterize how and why individuals use opioids in combination with these three psychoactive medications (PAMs).

METHODS

Participants (n = 103) were a convenience sample of adults attending a syringe service program who reported using a PAM in addition to opioids or opioid agonist therapies (buprenorphine or methadone). Face-to-face structured interviews consisted of closed and open-ended questions.

RESULTS

Patterns of PAM use varied. Risky use, including use of high doses and with other sedating medications, was common. Most individuals reported multiple medical reasons for use, even while reporting the PAM had mind-altering effects. Use of high doses of PAMs was associated with a history of overdose. Among those with a history of overdose, 32% reported that a PAM was involved.

CONCLUSION

The use of clonidine, gabapentin and promethazine among individuals who use opioids is complex. Providers should take individualized approaches to PAM prescribing, recognizing both the risks of PAMs and the potential unintended consequences of supply-side interventions in the era of the overdose crisis. Harm reduction interventions are needed to prevent PAM-involved overdoses.

Trends in Gabapentin Prescribing in a Commercially Insured U.S. Adult Population, 2009-2016

BACKGROUND

Gabapentin is prescribed for a variety of conditions and is often used off label. It is important to understand the prevalence of gabapentin prescribing and the characteristics of individuals who are prescribed gabapentin, given increasing concern regarding its potential for misuse.

OBJECTIVES

To (a) examine state- and region-level prevalence and trends in gabapentin prescribing from 2009 to 2016 and (b) characterize demographic and clinical characteristics of individuals prescribed gabapentin in a nationwide population of commercially insured adults.

METHODS

This retrospective, longitudinal study examined trends in gabapentin prescribing from 2009 to 2016. The study population included individuals aged 18-64 years who were enrolled in a commercial insurance plan at any point from 2009 to 2016. Individuals who were prescribed gabapentin were defined as beneficiaries with at least 1 gabapentin prescription claim in a calendar year (CY). A cross-sectional descriptive analysis was performed to examine differences in demographic and clinical characteristics of individuals prescribed or not prescribed gabapentin in CY 2016.

RESULTS

The prevalence of gabapentin prescribing nearly doubled from 2009 to 2016. During this time, gabapentin prescribing increased in every state (range: 44%-179%). State-specific prevalence rates in 2016 varied from 12.7 to 43.9 per 1,000 beneficiaries. Overall, 2.7% of beneficiaries filled ≥ 1 gabapentin prescription in 2016. Individuals prescribed gabapentin were more likely to fill opioid prescriptions (60.8% vs. 16.5%, P < 0.01); reside in the South (53.7% vs. 47%, P < 0.01); be female (62.5% vs. 52.3%, P < 0.01); and be aged 55-64 years (41.7% vs. 21.2%, P < 0.01) compared with the comparator. Individuals who were prescribed gabapentin also had significantly higher rates of seizure disorders, neuropathic pain, mental health disorders, substance use disorders, and diabetes.

CONCLUSIONS

The prevalence of gabapentin prescribing among a U.S. privately insured population has increased steadily in recent years. Additional research should examine coprescribing of gabapentin in the context of the opioid epidemic.

DISCLOSURES

The project described in this study was supported by the NIH National Center for Advancing Translational Sciences through grant number UL1TR001998. This study was also partially supported by grant number 2017-PM-BX-K026 (Data-Driven Responses to Prescription Drug Misuse in Kentucky) awarded by the Bureau of Justice Assistance. Viewpoints or opinions in this document are those of the authors and do not necessarily represent the official position or policies of the U.S. Department of Justice or the official views of the NIH. The authors do not have any conflicts of interest to report. Portions of this study have been previously presented in poster presentations at the 2019 Academy Health Annual Research Meeting; June 2-4, 2019; Washington, DC, and the 2019 University of Kentucky Substance Use Research Day; March 3, 2019; Lexington, KY.

Pregabalin Abuse in Combination With Other Drugs: Monitoring Among Methadone Patients

INTRODUCTION

In recent years, there has been an increase in the non-medical use of psychoactive prescription drugs including pregabalin (PGB). Studies have shown that multiple drug users and patients in methadone treatment programs administered PGB at high dosages in order to achieve euphoria, reduce withdrawal symptoms, or potentiate the effects of methadone. For these reasons, accurate toxicological monitoring is required for these high-risk individuals.

MATERIALS AND METHODS

The present study investigated whether PGB could be detected in the hair samples of 250 patients with a history of opiate dependency, and under toxicological surveillance assess their compliance with methadone maintenance therapy.

RESULTS

Opiates were found in 54/250 of all hair samples, while cannabis was present in 74/250 patients, cocaine was detected in 21/250 patients, and benzodiazepines without prescription were identified in 49/250 patients. As expected, methadone was present in all 250 patients (100%). PGB without prescription was found in the hair samples of 35/250 patients (14%). Of these, 91.43% were male, 48.57% were <30 y old, and 45.71% were between ages 30 and 50 y. There were no apparent associations among PGB use, daily methadone dosage, and duration of methadone maintenance therapy. Psychiatric comorbidities were present in 25.71% of the patients abusing PGB. Anxiety (55.56%) and depression (33.33%) were the most prevalent psychiatric disorders.

DISCUSSION

Most of the patients taking PGB (57.14%) used other drugs (especially opiates) concurrently. The utility of hair analysis is explained by easy and rapid sample collection and the ability of the hair to reflect long-term drug use and incorporate drug metabolites. The findings of this study suggested that PGB has significant potential for abuse by high-risk populations such as opioid users and patients with dual diagnosis. These risks are particularly high in cases of poly-drug use and drug intake that are not in compliance with prescription guidelines.

A repeated cross-sectional study of factors associated with pregabalin-positive poisoning deaths in Ireland

BACKGROUND

The increasing use of pregabalin and the presence of pregabalin in poisoning deaths, particularly with opioids, highlight it as a potential drug of abuse. In this study we examined factors associated with pregabalin-positive poisoning deaths (PPPD) between 2013 and 2016 in Ireland.

METHODS

Data were extracted from the National Drug-Related Deaths Index (NDRDI). Analysis included univariate and multivariate logistic regression to estimate unadjusted and adjusted odds ratios (OR) and 95 % confidence intervals (CI) for factors associated with PPPD (primary outcome) by logistic regression models for the total sample and stratified by gender.

RESULTS

Pregabalin was present on 240 (16 %) toxicology reports of 1489 poisoning deaths; significantly rising from 15 (4.5 %) in 2013 to 94 (26 %) in 2016. Women (AOR 2.69, 95 % CI: 1.95-3.70), opioid misuse (AOR 1.74, 95 % CI: 1.17-2.59), in receipt of treatment for problem drug use (AOR 1.95, 95 % CI: 1.33-2.86) and year of death (2016 vs 2013) (AOR 7.95, 95 % CI: 4.58-13.79) were associated with increased odds of PPPD. Alcohol dependence was associated with reduced odds of PPPD (AOR 0.59, 95 % CI: 0.41-0.85). For men, opioid misuse, in receipt of treatment for problem drug use, and year of death were associated with increased odds of PPPD, while alcohol dependence was associated with reduced odds of PPPD. For women, in receipt of treatment for problem drug use and year of death were associated with increased odds of PPPD.

CONCLUSIONS

Enhanced training to prescribers and treatment providers on the potential risks associated with pregabalin, particularly among people who use drugs, is required.

Characteristics Associated With U.S. Outpatient Opioid Analgesic Prescribing and Gabapentinoid Co-Prescribing

INTRODUCTION

A considerable burden of prescription and illicit opioid-related mortality and morbidity in the U.S. is attributable to potentially unnecessary or excessive opioid prescribing, and co-prescribing gabapentinoids may increase risk of harm. Data are needed regarding physician and patient characteristics associated with opioid analgesic and opioid analgesic-gabapentinoid co-prescriptions to elucidate targets for reducing preventable harm.

METHODS

Multiple logistic regression was utilized to examine patient and physician predictors of opioid analgesic prescriptions and opioid analgesic-gabapentinoid co-prescriptions in adult noncancer patients using the National Ambulatory Medical Care Survey 2015 public use data set. Potential predictors were selected based on literature review, clinical relevance, and random forest machine learning algorithms.

RESULTS

Among the 11.8% (95% CI=9.8%, 13.9%) of medical encounters with an opioid prescription, 16.2% (95% CI=12.6%, 19.8%) had a gabapentinoid co-prescription. Among all gabapentinoid encounters, 40.7% (95% CI=32.6%, 48.7%) had an opioid co-prescription. Predictors of opioid prescription included arthritis (OR=1.87, 95% CI=1.30, 2.69). Predictors of new opioid prescription included physician status as an independent contractor (OR=3.67, 95% CI=1.38, 9.81) or part owner of the practice (OR=3.34, 95% CI=1.74, 6.42). Predictors of opioid-gabapentinoid co-prescription included patient age (peaking at age 55-64 years; OR=35.67, 95% CI=4.32, 294.43).

CONCLUSIONS

Predictors of opioid analgesic prescriptions with and without gabapentinoid co-prescriptions were identified. These predictors can help inform and reinforce (e.g., educational) interventions seeking to reduce preventable harm, help identify populations for elucidating opioid-gabapentinoid risk-benefit profiles, and provide a baseline for evaluating subsequent public health measures.

Prescribed and non-prescribed gabapentin use among persons seeking inpatient opioid detoxification

BACKGROUND

Persons with opioid use disorder (OUD) are at increased risk for gabapentin misuse. Rising rates of concomitant gabapentin-opioid use in the U.S. are concerning given heightened risk of fatal overdose.

OBJECTIVE

To examine predictors of ever using gabapentin among persons seeking treatment for opioid use and to assess if reasons for gabapentin use differed by gender and how gabapentin was procured (prescribed, non-prescribed, or both).

METHOD

Persons with OUD were recruited from a managed withdrawal program. t-Tests and Pearson χ2 tests of independence were used to compare reasons for gabapentin use by gender and source of acquisition.

RESULTS

Among participants (n = 401; 69.1% male, 84.5% White, 86.8% sought treatment for heroin use, 90.0% insured), female gender, higher educational attainment, injection drug use (IDU), history of overdose, and chronic pain were associated with gabapentin use. Overall, reasons for use were similar across genders among those reporting a history of gabapentin use (65.8%), although males were more likely to use to get high than females. About half (47.0%) reported only using gabapentin that was not prescribed, 20.5% had only used prescribed gabapentin, and 32.5% reported prescribed and non-prescribed use. Persons prescribed gabapentin were most likely to use it to control pain (81.5%); for those using diverted gabapentin only and those reporting both prescribed and non-prescribed gabapentin use, the most common reasons for intake were to: get high, increase effects of heroin, substitute for opioids, and help with opioid withdrawal.

CONCLUSIONS

In this sample of people with OUD entering inpatient detoxification program, a majority reported a history of gabapentin use, with most using diverted gabapentin. The range of reasons for gabapentin use point to the need to better understand why co-use is common.

Prolonged ethanol administration prevents the development of tolerance to morphine-induced respiratory depression

BACKGROUND

Opioid users regularly consume other drugs such as alcohol (ethanol). Acute administration of ethanol can rapidly reverse tolerance to morphine-induced respiratory depression. However, alcohol consumption by opioid users is likely to occur over prolonged time periods. We have therefore sought to determine the effect of prolonged alcohol consumption on the development of tolerance to opioid respiratory depression.

METHODS

Mice were fed control or ethanol (5%) liquid diet for 16 days. On days 9-16 morphine tolerance was induced by administration of 3 priming injections of morphine followed by subcutaneous implantation of a morphine-filled osmotic mini-pump. Control mice received saline. Respiration was measured by plethysmography and the effect of an acute morphine challenge dose was measured on day 16 to assess the development of morphine tolerance.

RESULTS

Prolonged ethanol consumption for 14 days did not alter the respiratory depressant effect of an acute dose of morphine. Control mice treated with prolonged morphine developed tolerance to acute morphine respiratory depression whereas ethanol diet fed mice treated with prolonged morphine showed significant respiratory depression during morphine-pump treatment and remained sensitive to the respiratory depressant effect of the acute challenge dose of morphine. The ethanol consumption did not alter blood or brain levels of morphine, whilst conversely prolonged morphine treatment did not alter blood levels of ethanol.

CONCLUSIONS

Prolonged ethanol consumption prevents the development and maintenance of tolerance to the respiratory depressant effect of morphine. These data suggest that ethanol inhibition of tolerance will greatly increase the risk of fatal heroin overdose in humans.

Medicines associated with dependence or withdrawal: a mixed-methods public health review and national database study in England

BACKGROUND

Antidepressants, opioids for non-cancer pain, gabapentinoids (gabapentin and pregabalin), benzodiazepines, and Z-drugs (zopiclone, zaleplon, and zolpidem) are commonly prescribed medicine classes associated with a risk of dependence or withdrawal. We aimed to review the evidence for these harms and estimate the prevalence of dispensed prescriptions, their geographical distribution, and duration of continuous receipt using all patient-linked prescription data in England.

METHODS

This was a mixed-methods public health review, comprising a rapid evidence assessment of articles (Jan 1, 2008, to Oct 3, 2018; with searches of MEDLINE, Embase, and PsycINFO, and the Cochrane and King's Fund libraries), an open call-for-evidence on patient experience and service evaluations, and a retrospective, patient-linked analysis of the National Health Service (NHS) Business Services Authority prescription database (April 1, 2015, to March 30, 2018) for all adults aged 18 years and over. Indirectly (sex and age) standardised rates (ISRs) were computed for all 195 NHS Clinical Commissioning Groups in England, containing 7821 general practices for the geographical analysis. We used publicly available mid-year (June 30) data on the resident adult population and investigated deprivation using the English Indices of Multiple Deprivation (IMD) quintiles (quintile 1 least deprived, quintile 5 most deprived), with each patient assigned to the IMD quintile score of their general practitioner's practice for each year. Statistical modelling (adjusted incident rate ratios [IRRs]) of the number of patients who had a prescription dispensed for each medicine class, and the number of patients in receipt of a prescription for at least 12 months, was done by sex, age group, and IMD quintile.

FINDINGS

77 articles on the five medicine classes were identified from the literature search and call-for-evidence. 17 randomised placebo-controlled trials (6729 participants) reported antidepressant-associated withdrawal symptoms. Almost all studies were rated of very low, low, or moderate quality. The focus of qualitative and other reports was on patients' experiences of long-term antidepressant use, and typically sudden onset, severe, and protracted withdrawal symptoms when medication was stopped. Between April 1, 2017, and March 31, 2018, 11·53 million individuals (26·3% of residents in England) had a prescription dispensed for at least one medicine class: antidepressants (7·26 million [16·6%]), opioids (5·61 million [12·8%]), gabapentinoids (1·46 million [3·3%]), benzodiazepines (1·35 million [3·1%]), and Z-drugs (0·99 million [2·3%]). For three of these medicine classes, more people had a prescription dispensed in areas of higher deprivation, with adjusted IRRs (referenced to quintile 1) ranging from 1·10 to 1·24 for antidepressants, 1·20 to 1·85 for opioids, and 1·21 to 1·85 for gabapentinoids across quintiles, and higher ISRs generally concentrated in the north and east of England. In contrast, the highest ISRs for benzodiazepines and Z-drugs were generally in the southwest, southeast, and east of England, with low ISRs in the north. Z-drugs were associated with increased deprivation, but only at the highest quintile (adjusted IRR 1·11 [95% CI 1·01-1·22]). For benzodiazepines, prescribing was reduced for people in quintiles 4 (0·90 [0·85-0·96]) and 5 (0·89 [0·82-0·97]). In March, 2018, for each of medicine class, about 50% of patients who had a prescription dispensed had done so continuously for at least 12 months, with the highest ISRs in the north and east. Long-term prescribing was associated with a gradient of increased deprivation.

INTERPRETATION

In 1 year over a quarter of the adult population in England had a prescription dispensed for antidepressants, opioids (for non-cancer pain), gabapentinoids, benzodiazepines, or Z-drugs. Long-term (>12 months) prescribing is common, despite being either not recommended by clinical guidelines or of doubtful efficacy in many cases. Enhanced national and local monitoring, better guidance for personalised care, and better doctor-patient decision making are needed.

FUNDING

Public Health England.

Prescription of benzodiazepines, z-drugs, and gabapentinoids and mortality risk in people receiving opioid agonist treatment: Observational study based on the UK Clinical Practice Research Datalink and Office for National Statistics death records

BACKGROUND

Patients with opioid dependency prescribed opioid agonist treatment (OAT) may also be prescribed sedative drugs. This may increase mortality risk but may also increase treatment duration, with overall benefit. We hypothesised that prescription of benzodiazepines in patients receiving OAT would increase risk of mortality overall, irrespective of any increased treatment duration.

METHODS AND FINDINGS

Data on 12,118 patients aged 15-64 years prescribed OAT between 1998 and 2014 were extracted from the Clinical Practice Research Datalink. Data from the Office for National Statistics on whether patients had died and, if so, their cause of death were available for 7,016 of these patients. We identified episodes of prescription of benzodiazepines, z-drugs, and gabapentinoids and used linear regression and Cox proportional hazards models to assess the associations of co-prescription (prescribed during OAT and up to 12 months post-treatment) and concurrent prescription (prescribed during OAT) with treatment duration and mortality. We examined all-cause mortality (ACM), drug-related poisoning (DRP) mortality, and mortality not attributable to DRP (non-DRP). Models included potential confounding factors. In 36,126 person-years of follow-up there were 657 deaths and 29,540 OAT episodes, of which 42% involved benzodiazepine co-prescription and 29% concurrent prescription (for z-drugs these respective proportions were 20% and 11%, and for gabapentinoids 8% and 5%). Concurrent prescription of benzodiazepines was associated with increased duration of methadone treatment (adjusted mean duration of treatment episode 466 days [95% CI 450 to 483] compared to 286 days [95% CI 275 to 297]). Benzodiazepine co-prescription was associated with increased risk of DRP (adjusted HR 2.96 [95% CI 1.97 to 4.43], p < 0.001), with evidence of a dose-response effect, but showed little evidence of an association with non-DRP (adjusted HR 0.91 [95% CI 0.66 to 1.25], p = 0.549). Co-prescription of z-drugs showed evidence of an association with increased risk of DRP (adjusted HR 2.75 [95% CI 1.57 to 4.83], p < 0.001) but little evidence of an association with non-DRP (adjusted HR 0.79 [95% CI 0.49 to 1.28], p = 0.342). There was no evidence of an association of gabapentinoid co-prescription with DRP (HR 1.54 [95% CI 0.60 to 3.98], p = 0.373) but evidence of an association with increased non-DRP (HR 1.83 [95% CI 1.28 to 2.62], p = 0.001). Concurrent benzodiazepine prescription also increased mortality risk after consideration of duration of OAT (adjusted HR for DRP with benzodiazepine concurrent prescription 3.34 [95% CI 2.14 to 5.20], p < 0.001). The main limitation of this study is the possibility that unmeasured confounding factors led to an association between benzodiazepine prescription and DRP that is not causal.

CONCLUSIONS

In this study, co-prescription of benzodiazepine was specifically associated with increased risk of DRP in opioid-dependent individuals. Co-prescription of z-drugs and gabapentinoids was also associated with increased mortality risk; however, for z-drugs there was no evidence for a dose-response effect on DRP, and for gabapentinoids the increased mortality risk was not specific to DRP. Concurrent prescription of benzodiazepine was associated with longer treatment but still increased risk of death overall. Clinicians should be cautious about prescribing benzodiazepines to opioid-dependent individuals.

Trends in prior receipt of prescription opioid or adjuvant analgesics among patients with incident opioid use disorder or opioid-related overdose from 2006 to 2016

BACKGROUND

With increasing efforts to scrutinize and reduce opioid prescribing, limited data exist on the recent trend in receipt of prescription pain medications before diagnosis of opioid use disorder (OUD) or opioid-related overdose (OD).

METHODS

Using 2005-2016 Truven MarketScan Commercial Claims databases, we assessed trends in annual 1) incidence of OUD or OD and 2) prevalence of receipt of prescription opioids or four commonly-prescribed adjuvant analgesics among patients newly diagnosed with OUD/OD. Trends were examined in the overall sample and by 3 age groups, including youths (≤18 years), adults (19-64 years), and older adults (≥65 years).

RESULTS

The incidence of diagnosed OUD or OD increased more than 3-fold from 4.99 to 23.81 per 10,000 persons from 2006 to 2016, with the highest increase (14.18-fold) seen in older adults, followed by adults (3.53-fold), and youths (0.16-fold). Between 2006 and 2016, the proportion of patients with incident OUD/OD who received anticonvulsant adjuvant analgesics in the year before diagnosis increased (from 23.4% to 34.3% [P-trend = .005]) whereas the proportion receiving high-dose prescriptions opioids decreased (from 45.5% to 34.8% [P-trend =< .001]). A decreasing trend was observed in general for tricyclic antidepressants and serotonin and norepinephrine reuptake inhibitors.

DISCUSSION

In US commercially insured patients newly diagnosed with OUD/OD, receipt of high-dose opioid prescriptions preceding the diagnosis decreased over time, paralleled by increased use of anticonvulsants commonly prescribed for pain conditions. Further investigations are warranted to understand how prescribed and anticonvulsants contribute to the development of OUD/OD.

Prescribing trends of gabapentin, pregabalin, and oxycodone: a secondary analysis of primary care prescribing patterns in England

Background

The risk of iatrogenic harm from the use and misuse of prescription drugs such as gabapentin, pregabalin, and oxycodone is substantial. In recent years, deaths associated with these drugs in England have increased.

Aim

To characterise general practice prescribing trends for gabapentin, pregabalin, and oxycodone — termed dependence forming medicines (DFM) — in England and describe potential drivers of unwarranted variation (that is, very high prescribing).

Design & setting

This study is a retrospective secondary analysis of open source, publicly available government data from various sources pertaining to primary care demographics and prescriptions.

Method

This study used 5 consecutive years (April 2013–March 2018) of aggregate data to investigate longitudinal trends of prescribing and variation in prescribing trends at practice and clinical commissioning group (CCG) level.

Results

Annual prescriptions of gabapentin, pregabalin, and oxycodone increased each year over the period. Variation in prescribing trends was associated with GP practice deprivation quintile, where the most deprived GP practices prescribed 313% (P<0.001) and 238% (P<0.001) greater volumes of gabapentin and pregabalin per person respectively, than practices in the least deprived quintile. The highest prescribing CCGs of each of these drugs were predominantly in northern and eastern regions of England.

Conclusion

Substantial increases in gabapentin, pregabalin, and oxycodone prescriptions are concerning and will increase iatrogenic harm from drug-related morbidity and mortality. More research is needed to understand the large variation in prescribing between general practices, and to develop and implement interventions to reduce unwarranted variation and increase the appropriateness of prescribing of these drugs.

Global patterns of opioid use and dependence: harms to populations, interventions, and future action

We summarise the evidence for medicinal uses of opioids, harms related to the extramedical use of, and dependence on, these drugs, and a wide range of interventions used to address these harms. The Global Burden of Diseases, Injuries, and Risk Factors Study estimated that in 2017, 40·5 million people were dependent on opioids (95% uncertainty interval 34·3-47·9 million) and 109 500 people (105 800-113 600) died from opioid overdose. Opioid agonist treatment (OAT) can be highly effective in reducing illicit opioid use and improving multiple health and social outcomes-eg, by reducing overall mortality and key causes of death, including overdose, suicide, HIV, hepatitis C virus, and other injuries. Mathematical modelling suggests that scaling up the use of OAT and retaining people in treatment, including in prison, could avert a median of 7·7% of deaths in Kentucky, 10·7% in Kiev, and 25·9% in Tehran over 20 years (compared with no OAT), with the greater effects in Tehran and Kiev being due to reductions in HIV mortality, given the higher prevalence of HIV among people who inject drugs in those settings. Other interventions have varied evidence for effectiveness and patient acceptability, and typically affect a narrower set of outcomes than OAT does. Other effective interventions focus on preventing harm related to opioids. Despite strong evidence for the effectiveness of a range of interventions to improve the health and wellbeing of people who are dependent on opioids, coverage is low, even in high-income countries. Treatment quality might be less than desirable, and considerable harm might be caused to individuals, society, and the economy by the criminalisation of extramedical opioid use and dependence. Alternative policy frameworks are recommended that adopt an approach based on human rights and public health, do not make drug use a criminal behaviour, and seek to reduce drug-related harm at the population level.

Trends in gabapentinoid prescribing in patients with osteoarthritis: a United Kingdom national cohort study in primary care

OBJECTIVE

To investigate trends in gabapentinoid prescribing in patients with osteoarthritis (OA).

METHODS

Patients aged 40 years and over with a new OA diagnosis recorded between 1995 and 2015 were identified in the Clinical Practice Research Datalink (CPRD) and followed to first prescription of gabapentin or pregabalin, or other censoring event. We estimated the crude and age-standardised annual incidence rates of gabapentinoid prescribing, stratified by patient age, sex, geographical region, and time since OA diagnosis, and the proportion of prescriptions attributable to OA, or to other conditions representing licensed and unlicensed indications for a gabapentinoid prescription.

RESULTS

Of 383,680 newly diagnosed OA cases, 35,031 were prescribed at least one gabapentinoid. Irrespective of indication, the annual age-standardised incidence rate of first gabapentinoid prescriptions rose from 1.6 [95% confidence interval (CI): 1.3, 2.0] per 1000 person-years in 2000, to 27.6 (26.7, 28.4) in 2015, a trend seen across all ages and not explained by length of follow-up. Rates were higher among women, younger patients, and in Northern Ireland, Scotland and the North of England. Approximately 9% of first prescriptions could be attributed to OA, a further 13% to comorbid licensed or unlicensed indications.

CONCLUSION

Gabapentinoid prescribing in patients with OA increased dramatically between 1995 and 2015. In most cases, diagnostic codes for licensed or unlicensed indications were absent. Gabapentinoid prescribing may be attributable to OA in a significant proportion but evidence for their effectiveness in OA is lacking. Further research to investigate clinical decision making around prescribing these expensive and potentially harmful medicines is recommended.

Foot drop with a popliteal artery aneurysm due to heroin use: A case report

Drug addiction has become an important problem worldwide, and the number of heroin users has been rapidly increasing. There are serious complications related to intravenous drug use. Sharing injectors and using them multiple times cause septic and infective complications. Another important aspect of intravenous drug use is that it potentiates vascular damage. Contaminated injectors may induce pseudoaneurysms when applied directly into the vessel, endothelium, or surrounding tissues. Infected pseudoaneurysms may provoke necrosis, rupture, bleeding, and some dramatic results such as loss of extremity or death. Herein, we report a female case who had a history of long-term substance abuse in whom foot drop developed with a popliteal artery aneurysm.

Acute Experimental Pain Responses in Methadone- and Buprenorphine/Naloxone-Maintained Patients Administered Additional Opioid or Gabapentin: A Double-Blind Crossover Pilot Study

Objective

The study objective was to identify the analgesic efficacy of three different pharmacological strategies in patients receiving methadone or buprenorphine as opioid agonist treatment (OAT). The three pharmacological approaches, a) increasing maintenance methadone/buprenorphine dose by 30%, b) adding oxycodone, or c) adding a single dose of gabapentin, were compared with a control condition of the participant’s usual OAT dose.

Design

A randomized, controlled, double-blinded, double-dummy, within-subject crossover study.

Subjects

Nine participants on stable doses of methadone and eight participants on stable doses of buprenorphine were recruited.

Setting

An outpatient opioid treatment clinic in inner city Sydney, Australia.

Methods

The cold pressor tolerance test was used to examine experimental pain threshold and tolerance. Ratings of subjective drug effects and safety measures (physiological and cognitive) were assessed.

Results

There was no difference in the primary outcome measures of pain thresholds or tolerance between the conditions examined. Interindividual variability was evident. Differences in some subjective measures were identified, including lower pain recall, lower “bad effects,” and higher global satisfaction in the additional methadone condition. In the buprenorphine arm, increased drug liking and “bad effects” were detected with oxycodone administration, while increased subjective intoxication was identified with gabapentin.

Conclusions

There was no evidence of an objective improvement in analgesia with any condition compared with control. Further research is required to optimize pain management strategies in this population.

Rising pregabalin use and misuse in Australia: trends in utilization and intentional poisonings

BACKGROUND AND AIMS

Pregabalin is a gamma-aminobutyric acid (GABA) analogue, used to treat neuropathic pain and epilepsy. Pregabalin was registered in Australia in 2005, and subsidized publically in 2013. We aimed to describe Australian patterns of pregabalin use and intentional poisoning, and identify people potentially at high risk of misuse.

DESIGN AND SETTING

Population-based retrospective cohort study of dispensings in the 10% sample of Australian Pharmaceutical Benefits Scheme (July 2012-February 2017); intentional poisoning calls to New South Wales Poisons Information Centre (NSWPIC) (2004-2016); intentional poisonings in two Australian toxicology service databases; and poisoning fatalities in NSW coronial records (2005-2016).

PARTICIPANTS

A total of 122 572 people dispensed pregabalin, people with intentional pregabalin overdoses managed by NSWPIC and the toxicology services and pregabalin-associated deaths referred to the NSW coroner.

MEASUREMENTS

Trends in dispensing, poisoning, death; demographics and patient characteristics, proportion of users at high risk of misuse (latent class analysis, LCA) and characteristics of high-risk users.

FINDINGS

Pregabalin dispensing increased by 73 424 per year [95% confidence interval (CI) = 61726-85 121 P < 0.001] between 2013 and 2016. NSWPIC received 1158 reports of intentional pregabalin poisonings, with a 53.8% increase per year, 2005-2016 (95% CI = 44.0-64.2%, P < 0.001). We identified 88 pregabalin-associated deaths, 57.8% yearly increase (95% CI = 30.0-91.6%, P < 0.001). Patients overdosing on pregabalin commonly co-ingested opioids, benzodiazepines and illicit drugs, and had high rates of psychiatric and substance use comorbidities; 14.7% of pregabalin users were classed by the LCA as at high risk of misuse, and were more likely to be younger, male, co-prescribed benzodiazepines or opioids, have more individual prescribers and higher pregabalin strengths dispensed.

CONCLUSIONS

There has been a dramatic increase in pregabalin use, poisonings and deaths in Australia since it became subsidized publicly in 2013. One in seven Australians dispensed pregabalin appears to be at high risk of misuse.

Misuse and Mortality Related to Gabapentin and Pregabalin are Being Under-Estimated: A Two-Year Post-Mortem Population Study

Due to the rise in their misuse and associated mortality, the UK government is reclassifying gabapentin (GBP) and pregabalin (PGL) to Class C controlled drugs from April 2019. However, it is impossible to gauge the extent of their use with current post-mortem toxicological screening, where GBP and PGL are only screened for if they are mentioned in the case documents. This study determines the prevalence of GBP and PGL, the potential extent of their under-reporting and poly-drug use in a post-mortem population. Between 1 January 2016 and 31 December 2017, 3,750 deceased from Coroners’ cases in London and South East England underwent a routine drugs screen and a specific screen for GBP and PGL. The prevalence of both drugs was determined in the cohort and the subcategories of heroin users and non-heroin-users. The prevalence of both drugs was compared to tramadol (Class C drug). Case documents were reviewed to investigate the under-reporting of GBP and PGL and poly-drug use. Of 3,750 samples analyzed, 118 (3.1%) were positive for GBP, 229 (6.1%) for PGL and 120 (3.2%) were positive for tramadol. If routine analysis without additional screening of GBP and PGL had been performed in this cohort, GBP would have been under-reported by 57.6% (P < 0.0001) and PGL by 53.7% (P < 0.0001) in deaths. The most common drug group observed with GBP and PGL was non-heroin-related opioids at 60.2% and 64.6%, respectively. In total 354 deceased (9.4%) were heroin users. GBP was positive in 23 (6.5%) of these cases and PGL was positive in 69 (19.5%). The prevalence of PGL in heroin users (19.5%) was 4.1 times greater than in non-heroin users (4.7%) (P < 0.0001). GBP and PGL are being significantly under reported in fatalities. Both drugs are extensively used with opioids. The prevalence of PGL in heroin users is highly significant.

Anesthesia considerations and post-operative pain management in pregnant women with chronic opioid use

The prevalence of opioid use disorder in pregnancy has escalated markedly in recent years. Chronic opioid use during pregnancy poses several challenges for providing adequate analgesia and anesthesia in the peripartum period. These challenges include the potential for withdrawal, opioid tolerance and opioid-induced hyperalgesia. Here we discuss alterations in analgesic pharmacokinetics and pharmacodynamics that are associated with chronic opioid use. In addition, when treating pain in patients with opioid use disorder it is important to distinguish between different subgroups. In this review, we will discuss practical management strategies for parturients with (1) untreated opioid use disorder, (2) parturients on medication-assisted treatment (methadone, buprenorphine) and (3) patients recovering from opioid use disorder that are currently abstinent. Finally, we offer an overview of non-opioid strategies that may be utilized as part of a multimodal approach to providing optimal analgesia in this patient population.

Patterns of gabapentin and pregabalin use and misuse: Results of a population-based cohort study in France

AIMS

The aim of this study was to assess the use and factors associated with the misuse of gabapentin and pregabalin in the general French population, through a cohort study in the EGB (General Sample of Beneficiaries), a national representative sample of the French general population.

METHODS

New users of gabapentin and pregabalin were identified from June 2006 to December 2014, and new users of duloxetine served as control group. Misuse was defined as a use of higher daily doses than recommended. Cox proportional hazard regression models were performed to identify associated factors of misuse.

RESULTS

Misuse was more frequent in the 8692 new users of pregabalin (12.8%) than in the 1963 gabapentin (6.6%) or the 3214 duloxetine new users (9.7%) (P < 0.001). Factors associated with misuse were pregabalin (hazard ratio [HR] 1.48; 95% confidence interval [CI] [1.29-1.69]), age (HR_{[18-45] versus > 70 years} 1.98 [1.70-2.31] and HR_{[58-70] versus > 70 years} 1.25 [1.06-1.47]), multiple prescribers (HR_{2 or 3 versus 1 prescriber} 1.29 [1.15-1.45]; HR_{4 or more versus 1 prescriber} 1.54 [1.30-1.83]), cancer (1.28 [1.11-1.47]), multiple sclerosis (1.53 [1.07-2.18]), neuropathy (1.85 [1.19-2.89]), depression (1.26 [1.07-1.49]) and methadone (2.61 [1.16-5.84]). After this first episode of drug misuse, 11.6% of gabapentin and 10.7% of pregabalin misusers developed a primary addiction.

CONCLUSION

In a cohort of new users, misuse is more likely to occur in new users of pregabalin, with different associated factors of misuse compared to gabapentin and duloxetine. Health professionals and prescribers must be aware of this misuse potential, which could lead to abuse and dependence.

Gabapentin and pregabalin to treat aggressivity in dementia: a systematic review and illustrative case report

AIMS

The prevalence of dementia is rising as life expectancy increases globally. Behavioural and psychological symptoms of dementia (BPSD), including agitation and aggression, are common, presenting a challenge to clinicians and caregivers.

METHODS

Following PRISMA guidelines, we systematically reviewed evidence for gabapentin and pregabalin against BPSD symptoms of agitation or aggression in any dementia, using six databases (Pubmed, CINHL, PsychINFO, HealthStar, Embase, and Web of Science). Complementing this formal systematic review, an illustrative case of a patient with BPSD in mixed Alzheimer's/vascular dementia, who appeared to derive benefits in terms of symptom control and functioning from the introduction of gabapentin titrated up to 3600 mg day^-1 alongside other interventions, is presented.

RESULTS

Twenty-four relevant articles were identified in the systematic review. There were no randomized trials. Fifteen papers were original case series/case reports of patients treated with these compounds, encompassing 87 patients given gabapentin and six given pregabalin. In 12 of 15 papers, drug treatment was effective in the majority of cases. The remaining nine papers were solely reviews, of which two were described as systematic but predated PRISMA guidelines. Preliminary low-grade evidence based on case series and case reviews suggests possible benefit of gabapentin and pregabalin in patients with BPSD in Alzheimer's disease. These benefits cannot be confirmed until well-powered randomized controlled trials are undertaken. Evidence in frontotemporal dementia is lacking.

CONCLUSION

Gabapentin and pregabalin could be considered for BPSD when medications having stronger evidence bases (risperidone, other antipsychotics, carbamazepine and citalopram) have been ineffective or present unacceptable risks of adverse outcomes.

Benefits and harms of pregabalin in the management of neuropathic pain: a rapid review and meta-analysis of randomised clinical trials

OBJECTIVE

To assess the benefits and harms of pregabalin in the management of neuropathic pain.

DESIGN

Rapid review and meta-analysis of phase III, randomised, placebo-controlled trials.

PARTICIPANTS

Adults aged 18 years and above with neuropathic pain defined according to the International Association for the Study of Pain criteria.

INTERVENTIONS

Pregabalin or placebo.

PRIMARY AND SECONDARY OUTCOME MEASURES

Our primary outcomes were pain (as measured using validated scales) and adverse events. Our secondary outcomes were sleep disturbance, quality of life, Patient Global Impression of Change, Clinician Global Impression scale, anxiety and depression scores, overall discontinuations and discontinuations because of adverse events.

RESULTS

We included 28 trials comprising 6087 participants. The neuropathic pain conditions studied were diabetic peripheral neuropathy, postherpetic neuralgia, herpes zoster, sciatica (radicular pain), poststroke pain and spinal cord injury-related pain. Patients who took pregabalin reported significant reductions in pain (numerical rating scale (NRS)) compared with placebo (standardised mean difference (SMD) -0.49 (95% CI -0.66 to -0.32, p<0.00001), very low quality evidence). Pregabalin significantly reduced sleep interference scores (NRS) compared with placebo (SMD -0.38 (95% CI -0.50 to -0.26, p<0.00001), moderate quality evidence. Pregabalin significantly increased the risk of adverse events compared with placebo (RR 1.33 (95% CI 1.23 to 1.44, p<0.00001, low quality evidence)). The risks of experiencing weight gain, somnolence, dizziness, peripheral oedema, fatigue, visual disturbances, ataxia, non-peripheral oedema, vertigo and euphoria were significantly increased with pregabalin. Pregabalin was significantly more likely than placebo to lead to discontinuation of the drug because of adverse events (RR 1.91 (95% CI 1.54 to 2.37, p<0.00001), low quality evidence).

CONCLUSION

Pregabalin has beneficial effects on some symptoms of neuropathic pain. However, its use significantly increases the risk of a number of adverse events and discontinuation due to adverse events. The quality of the evidence from journal publications is low.

Patterns and history of prescription drug use among opioid-related drug overdose cases in British Columbia, Canada, 2015-2016

BACKGROUND

British Columbia is the epicenter of the current fentanyl-related overdose crisis in Canada. Our study characterizes prescribing histories of people who had an opioid-related overdose compared to matched controls.

METHODS

We examined linked administrative data for individuals who overdosed between January 1, 2015 and November 30, 2016. Past prescriptions over five years were assessed for opioids for pain, opioid agonist therapy, benzodiazepines/z-drugs, antidepressants, antipsychotics, gabapentinoids, mood stabilizers and anti-epileptics, muscle relaxants, and other sedating medications. Prescribing history of 9964 cases was compared with that of 49,820 matched controls.

RESULTS

Overdose cases were more likely to be prescribed opioids for pain and to have used prescription opioids on a long-term basis in the previous five years compared to controls. However, at the time of overdose, 92% of men and 86% of women did not have an active opioid for pain prescription, and approximately half had not filled one in the past five years. Those who overdosed tended to have more prescriptions for psychotropic substances than controls. Fewer than 10% of cases had an active prescription for opioid agonist therapy and most were not on treatment in the past.

CONCLUSIONS

Low prevalence of active prescriptions for opioids for pain at the time of overdose suggests that opioid prescribing plays a limited short-term impact in the current fentanyl-related crisis of overdoses. While liberal opioid prescribing practices may have contributed to the development of the current overdose crisis, regulation and enforcement of clinicians' prescribing practices will likely have limited impact in reducing overdoses.

Psychopharmacology: From serendipitous discoveries to rationale design, but what next?

Psychopharmacology really developed as a discipline from the mid-20th century with the discovery of a number of new classes of psychoactive drugs which could modify behaviour. These drugs were discovered as a consequence of clinical observations of patients, often being treated for other conditions. These serendipitous discoveries were the start of an era of drug development which has led to the antidepressants, antipsychotics, anxiolytics and mood stabilisers used today. Subsequent research focused on understanding why these drugs were effective, and used this information to develop a second generation of drugs that were more selective for their therapeutic targets, and therefore had reduced side effects and improved safety and tolerability. After a period of decline in new discoveries and withdrawal of the majority of the major pharmaceutical companies from active development programmes in psychiatry, new avenues are emerging fuelling renewed interest in this area.