Gabapentin drug misuse signals: A pharmacovigilance assessment using the FDA adverse event reporting system

Post-marketing safety assessment of constipation drugs: a real-world pharmacovigilance study based on FAERS database

BACKGROUND

Laxatives are widely used in the treatment of constipation, but they also have brought many adverse reactions to patients.

METHODS

We conducted a pharmacovigilance analysis based on the United States Food and Drug Administration Adverse Event Reporting System (FAERS) database to analyze the adverse events of six constipation drugs (linaclotide, lubiprostone, prucalopride, naloxegol, naldemedine, and plecanatide) and to search for clinically meaningful adverse reaction signals. We used disproportionality analysis as the main analysis method to detect pharmacovigilance signals, which includes Frequentist methods and Bayesian methods.

RESULTS

Among the reports of the six drugs, more adverse reactions were reported from females than males, and the number of adverse reactions reported was higher in the group of 60-89 years. Linaclotide had the lowest proportion of serious adverse event reports (4.38%), while naldemedine had the highest proportion of serious adverse event reports (25.57%). According to the classification of system organ classification (SOC), the number of gastrointestinal adverse events (N = 8321) was the largest.

CONCLUSIONS

The adverse reactions of constipation drugs were mainly gastrointestinal symptoms such as diarrhea, abdominal pain and abdominal distension. Linaclotide has the highest safety, and more studies are needed to analyze the cardiovascular safety of lubiprostone.

Evaluating drug withdrawal syndrome risks through food and drug administration adverse event reporting system: a comprehensive disproportionality analysis

Objective

The study aims to identify the drugs associated with drug withdrawal syndrome in the Food and Drug Administration Adverse Event Reporting System (FAERS) and estimate their risks of causing withdrawal syndrome.

Methods

All the data were collected from FAERS from the first quarter of 2004 to the third quarter of 2023. Disproportionality analyses of odds ratio (ROR) and proportional reported ratio were conducted to identify potential adverse effects signal of drug withdrawal syndrome.

Results

A total of 94,370 reports related to withdrawal syndrome from the data. The top 50 drugs with most frequency reported were analyzed, and 29 exhibited a positive signal based on the number of reports. The top three categories of drugs with positive signals included opioids, antidepressant drugs and antianxiety drugs. Other classifications included opioid antagonist, muscle relaxant, antiepileptic drugs, analgesics, hypnotic sedative drugs and antipsychotic drugs.

Conclusion

Our analysis of FAERS data yielded a comprehensive list of drugs associated with withdrawal syndrome. This information is vital for healthcare professionals, including doctors and pharmacists, as it aids in better recognition and management of withdrawal symptoms in patients undergoing treatment with these medications.

Gabapentinoids for the treatment of stroke

ABSTRACT

Gabapentinoid drugs (pregabalin and gabapentin) have been successfully used in the treatment of neuropathic pain and in focal seizure prevention. Recent research has demonstrated their potent activities in modulating neurotransmitter release in neuronal tissue, oxidative stress, and inflammation, which matches the mechanism of action via voltage-gated calcium channels. In this review, we briefly elaborate on the medicinal history and ligand-binding sites of gabapentinoids. We systematically summarize the preclinical and clinical research on gabapentinoids in stroke, including ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, seizures after stroke, cortical spreading depolarization after stroke, pain after stroke, and nerve regeneration after stroke. This review also discusses the potential targets of gabapentinoids in stroke; however, the existing results are still uncertain regarding the effect of gabapentinoids on stroke and related diseases. Further preclinical and clinical trials are needed to test the therapeutic potential of gabapentinoids in stroke. Therefore, gabapentinoids have both opportunities and challenges in the treatment of stroke.

Pharmacovigilance of esketamine nasal spray: an analysis of the FDA adverse event reporting system database

Esketamine nasal spray (ESK-NS) is a new drug for treatment-resistant depression, and we aimed to detect and characterize the adverse events (AEs) of ESK-NS using the Food and Drug Administration (FDA) adverse event reporting system (FAERS) database between 2019 Q1 and 2023 Q4. Reporting odds ratio (ROR), proportional reporting ratio (PRR), and multi-item gamma Poisson shrinker (MGPS) were performed to detect risk signals from the FAERS data to identify potential ESK-NS-AEs associations. A total of 14,606 reports on AEs with ESK-NS as the primary suspected drug were analyzed. A total of 518 preferred terms signals and 25 system organ classes mainly concentrated in psychiatric disorders (33.20%), nervous system disorders (16.67%), general disorders and administration site conditions (14.21%), and others were obtained. Notably, dissociation (n = 1,093, ROR 2,257.80, PRR 899.64, EBGM 876.86) exhibited highest occurrence rates and signal intensity. Moreover, uncommon but significantly strong AEs signals, such as hand-eye coordination impaired, feeling guilty, and feelings of worthlessness, were observed. Additionally, dissociative disorder (n = 57, ROR 510.92, PRR 506.70, EBGM 386.60) and sedation (n = 688, ROR 172.68, PRR 155.53, and EBGM 142.05) both presented strong AE signals, and the former is not recorded in the Summary of Product Characteristics (SmPC). In clinical applications, close attention should be paid to the psychiatric disorders and nervous system disorders, especially dissociation. Meanwhile, clinical professionals should be alert for the occurrence of AEs signals not mentioned in the SmPC and take preventive measures to ensure the safety of clinical use.

Direct-To-Definitive Urine and Oral Fluid Test Results for Unscreened and Rarely Screened Drugs in Individuals Applying for Methadone Treatment in 7 U.S. States

The standard protocol in addiction treatment/pain management is to conduct immunoassay screens for major drugs subject to misuse, followed by confirmatory testing of positive results. However, this may miss unscreened or rarely screened drugs that could pose risks, especially to polydrug users. We sought to determine the prevalences of unscreened/rarely screened drugs in a sample of individuals misusing drugs in 7 U.S. states, and to compare the results of urine vs. oral testing for these drugs by direct-to-definitive liquid chromatography/tandem mass spectrometry (LC-MS-MS). The five drugs with the highest prevalences were: gabapentin (16.8%), quetiapine (6.2%), chlorpheniramine (5.3%), hydroxyzine (4.9%), and ephedrine (3.5%). All have clinical significance as indicated by severity of possible side effects, interactions with other drugs, and/or misuse potential. Drugs were generally detected more frequently in oral fluid than urine, but gabapentin was more frequently detected in urine. The prevalences of the included drugs seem high enough, and their clinical significance important enough, to warrant consideration of expanding clinical drug test panels, either by direct-to-definitive testing or the addition of selected immunoassay screens when available. Oral fluid was usually more suitable than urine as the test matrix, given the higher rates of detection in oral fluid for most substances included in this study.

Concurrent Gabapentin and Opioid Use and Risk of Mortality in Medicare Recipients with Non-Cancer Pain

Gabapentin is prescribed for pain and is perceived as safe generally. However, gabapentin can cause respiratory depression, exacerbated by concomitant central nervous system depressants (e.g., opioids), a concern for vulnerable populations. We compared mortality rates among new users of either gabapentin or duloxetine with or without concurrent opioids in the 20% Medicare sample. We conducted a new-user design retrospective cohort study, in Medicare enrollees ages 65-89 years with noncancer chronic pain and no severe illness who filled prescriptions between 2015 and 2018 for gabapentin (n = 233,060) or duloxetine (n = 34,009). Daily opioid doses, estimated in morphine milligram equivalents (MMEs), were classified into none, low (0 < MME < 50), and high (≥ 50 MME), based on Centers for Disease Control and Prevention (CDC) recommendations. The outcomes were all-cause mortality (primary) and out-of-hospital mortality (secondary). We used inverse probability of treatment weighting to adjust for differences between gabapentin and duloxetine users. During 116,707 person-years of follow-up, 1,379 patients died. All-cause mortality rate in gabapentin users was 12.16 per 1,000 person-years vs. 9.94 per 1,000 in duloxetine users. Risks were similar for users with no concurrent opioids (adjusted hazard ratio (aHR) = 1.03, 95% confidence interval (CI): 0.80-1.31) or low-dose daily opioids (aHR = 1.06, 95% CI: 0.63-1.76). However, gabapentin users receiving concurrent high-dose daily opioids had an increased rate of all-cause mortality compared with duloxetine users on high-dose opioids (aHR = 2.03, 95% CI: 1.19-3.46). Out-of-hospital mortality yielded similar results. In this retrospective cohort study of Medicare beneficiaries, concurrent use of high-dose opioids and gabapentin was associated with a higher all-cause mortality risk than that for concurrent use of high-dose opioids and duloxetine.

An enhanced recovery after surgery protocol for facial feminization surgery reduces perioperative opioid usage, pain, and hospital stay

BACKGROUND

Prescription drug misuse in transgender individuals is estimated to be three times higher than that of the general population in the United States, suggesting that opioid-reduction strategies deserve significant consideration in gender-affirming surgeries. In this work, we describe the implementation of an enhanced recovery after surgery (ERAS) protocol to reduce opioid use after facial feminization surgery.

METHODS

A total of 79 patients who underwent single-stage facial feminization surgery before (n = 38) or after (n = 41) ERAS protocol implementation were included. Primary outcomes assessed were perioperative opioid consumption (morphine equivalent dose/kilogram, MED/kg), average patient-reported pain scores, and length of hospital stay. Comparisons between groups and multivariable linear regression analyses were conducted to define the contribution of the ERAS protocol to each of the three primary outcomes.

RESULTS

Age, body mass index, mental health diagnoses, and length of surgery did not differ between pre-ERAS and ERAS groups. Compared to pre-ERAS patients, patients treated under the ERAS protocol consumed less opioids (median [interquartile range, IQR], 0.8 [0.5-1.1] versus 1.5 [1.0-2.1] MED/kg, p < 0.001), reported lower pain scores (2.5 ± 1.8 versus 3.7 ± 1.6, p = 0.002), and required a shorter hospital stay (median [IQR], 27.3 [26.3-49.8] versus 32.4 [24.8-39.1] h, p < 0.001). When controlling for other contributing variables such as previous gender-affirming surgeries, mental health diagnoses, and length of surgery using multivariable linear regression analyses, ERAS protocol implementation independently predicted reduced opioid use, lower pain scores, and shorter hospital stay after facial feminization surgery.

CONCLUSIONS

The current work details an ERAS protocol for facial feminization surgery that reduces perioperative opioid consumption, patient-reported pain scores, and hospital stays.

N-palmitoylethanolamide synergizes the antinociception of morphine and gabapentin in the formalin test in mice

OBJECTIVE

The antinociceptive pharmacological interaction between N-palmitoylethanolamide (PEA) and morphine (MOR), as well as gabapentin (GBP), was investigated to obtain synergistic antinociception at doses where side effects were minimal. In addition, the possible antinociceptive mechanism of PEA + MOR or PEA + GBP combinations was explored.

METHODS

Individual dose-response curves (DRCs) of PEA, MOR and GBP were evaluated in female mice in which intraplantar nociception was induced with 2% formalin. Isobolographic method was used to detect the pharmacological interaction in the combination of PEA + MOR or PEA + GBP.

KEY FINDINGS

The ED50 was calculated from the DRC; the order of potency was MOR > PEA > GBP. The isobolographic analysis was obtained at a 1:1 ratio to determine the pharmacological interaction. The experimental values of flinching (PEA + MOR, Zexp = 2.72 ± 0.2 μg/paw and PEA + GBP Zexp = 2.77 ± 0.19 μg/paw) were significantly lower than those calculated theoretically (PEA + MOR Zadd = 7.78 ± 1.07 and PEA + GBP Zadd = 24.05 ± 1.91 μg/paw), resulting in synergistic antinociception. Pretreatment with GW6471 and naloxone demonstrated that peroxisome proliferator-activated receptor alpha (PPARα) and opioid receptors are involved in both interactions.

CONCLUSIONS

These results suggest that MOR and GBP synergistically enhance PEA-induced antinociception through PPARα and opioid receptor mechanisms. Furthermore, the results suggest that combinations containing PEA with MOR or GBP could be of interest in aiding the treatment of inflammatory pain.

Neonatal withdrawal syndrome following in utero exposure to antidepressants: a disproportionality analysis of VigiBase, the WHO spontaneous reporting database

BACKGROUND

Evidence on neonatal withdrawal syndrome following antidepressant intrauterine exposure is limited, particularly for antidepressants other than selective serotonin reuptake inhibitor (SSRIs).

METHODS

In our case/non-case pharmacovigilance study, based on VigiBase®, the WHO database of suspected adverse drug reactions, we estimated reporting odds ratio (ROR) and the Bayesian information component (IC) with 95% confidence/credibility intervals (CI) as measures of disproportionate reporting of antidepressant-related neonatal withdrawal syndrome. Antidepressants were first compared to all other medications, then to methadone, and finally within each class of antidepressants: SSRIs, tricyclics (TCA) and other antidepressants. Antidepressants were ranked in terms of clinical priority, based on semiquantitative score ratings. Serious v. non-serious reports were compared.

RESULTS

A total of 406 reports of neonatal withdrawal syndrome in 379 neonates related to 15 antidepressants were included. Disproportionate reporting was detected for antidepressants as a group as compared to all other drugs (ROR: 6.18, 95% CI 5.45-7.01, IC: 2.07, 95% CI 1.92-2.21). Signals were found for TCAs (10.55, 95% CI 8.02-13.88), followed by other antidepressants (ROR: 5.90, 95% CI 4.74-7.36) and SSRIs (ROR: 4.68, 95% CI 4.04-5.42). Significant disproportionality emerged for all individual antidepressants except for bupropion, whereas no disproportionality for any antidepressant was detected v. methadone. Eleven antidepressants had a moderate clinical priority score and four had a weak one. Most frequent symptoms included respiratory symptoms (n = 106), irritability/agitation (n = 75), tremor (n = 52) and feeding problems (n = 40).

CONCLUSIONS

Most antidepressants are associated with moderate signals of disproportionate reporting for neonatal withdrawal syndrome, which should be considered when prescribing an antidepressant during pregnancy, irrespective of class.

Duloxetine, Gabapentin, and the Risk for Acute Myocardial Infarction, Stroke, and Out-of-Hospital Death in Medicare Beneficiaries With Non-Cancer Pain

OBJECTIVE

Duloxetine is a serotonin-norepinephrine reuptake inhibitor prescribed for musculoskeletal and other forms of chronic pain. Its dual pharmacologic properties have the potential to either raise or lower cardiovascular risk: adrenergic activity may increase the risk for acute myocardial infarction (AMI) and stroke, but antiplatelet activity may decrease risk. Gabapentin is another nonopioid medication used to treat pain, which is not thought to have adrenergic/antiplatelet effects. With the current emphasis on the use of nonopioid medications to treat patients with chronic pain, assessing cardiovascular risks associated with these medications among high-risk patients is important.

MATERIALS AND METHODS

We conducted a retrospective cohort study among a 20% sample of Medicare enrollees, aged 65 to 89, with chronic pain who were new users between 2015 and 2018 of either duloxetine (n = 34,009) or gabapentin (n = 233,060). We excluded individuals with cancer or other life-threatening conditions at study drug initiation. The primary outcome was a composite of AMI, stroke, and out-of-hospital mortality. We adjusted for comorbidity differences with time-dependent inverse probability of treatment weighting.

RESULTS

During 115,668 person-years of follow-up, 2361 patients had the composite primary outcome; the rate among new users of duloxetine was 16.7/1000 person-years compared with new users of gabapentin (21.1/1000 person-years), adjusted hazard ratio = 0.98 (95% CI: 0.83, 1.16). Results were similar for the individual components of the composite outcome as well as in analyses stratified by demographic and clinical characteristics.

DISCUSSION

In summary, cohort Medicare patients with non-cancer pain beginning treatment with duloxetine had rates of AMI, stroke, and out-of-hospital mortality comparable to those who initiated gabapentin.

An algorithm to identify gabapentin misuse and/or abuse in administrative claims data

BACKGROUND

Despite gabapentin's misuse and abuse potential and associated adverse events, few algorithms are available to detect gabapentin misuse and/or abuse in claims data. This study aims to develop an algorithm to identify gabapentin misuse and/or abuse in administrative claims data.

METHODS

We developed an algorithm to identify gabapentin misuse and/or abuse over a 12-month period based on input from 21 clinical experts. We implemented the algorithm among 334,128 patients with at least one dispensed prescription of gabapentin between December 1, 2017 and December 1, 2018 in the IBM® MarketScan® Research Databases. We described the characteristics of patients who potentially misused and/or abused gabapentin and assessed factors associated with misuse and/or abuse using logistic regression.

RESULTS

The algorithm identified 17.6% of patients with gabapentin use who potentially misused and/or abused gabapentin. Factors associated with potential gabapentin misuse and/or abuse included men (adjusted odds ratio (aOR): 1.08; 95% confidence interval (CI): 1.06-1.10), comorbid conditions (e.g., drug and alcohol dependence (aOR: 1.31; 95% CI: 1.24-1.39); bipolar disorder (aOR: 1.34; 95% CI: 1.27-1.41)), and medication use (e.g., opioids (aOR: 1.23; 95% CI: 1.20-1.26), muscle relaxants (aOR: 1.24; 95% CI: 1.21-1.27), or serotonin-norepinephrine reuptake inhibitors (aOR: 1.33; 95% CI: 1.29-1.36)).

CONCLUSIONS

Approximately one in six patients with gabapentin use potentially misused and/or abused gabapentin in a large commercial claims database. Multiple comorbidities and drug use were associated with gabapentin misuse and/or abuse. Monitoring requirements and individualized safety measures should be put in place for patients at elevated risks of gabapentin misuse and/or abuse.

Pharmacovigilance Signals of the Opioid Epidemic over 10 Years: Data Mining Methods in the Analysis of Pharmacovigilance Datasets Collecting Adverse Drug Reactions (ADRs) Reported to EudraVigilance (EV) and the FDA Adverse Event Reporting System (FAERS)

In the past twenty years, the consumption of opioid medications has reached significant proportions, leading to a rise in drug misuse and abuse and increased opioid dependence and related fatalities. Thus, the purpose of this study was to determine whether there are pharmacovigilance signals of abuse, misuse, and dependence and their nature for the following prescription opioids: codeine, dihydrocodeine, fentanyl, oxycodone, pentazocine, and tramadol. Both the pharmacovigilance datasets EudraVigilance (EV) and the FDA Adverse Events Reporting System (FAERS) were analyzed to identify and describe possible misuse-/abuse-/dependence-related issues. A descriptive analysis of the selected Adverse Drug Reactions (ADRs) was performed, and pharmacovigilance signal measures (i.e., reporting odds ratio, proportional reporting ratio, information component, and empirical Bayesian geometric mean) were computed for preferred terms (PTs) of abuse, misuse, dependence, and withdrawal, as well as PTs eventually related to them (e.g., aggression). From 2003 to 2018, there was an increase in ADR reports for the selected opioids in both datasets. Overall, 16,506 and 130,293 individual ADRs for the selected opioids were submitted to EV and FAERS, respectively. Compared with other opioids, abuse concerns were mostly recorded in relation to fentanyl and oxycodone, while tramadol and oxycodone were more strongly associated with drug dependence and withdrawal. Benzodiazepines, antidepressants, other opioids, antihistamines, recreational drugs (e.g., cocaine and alcohol), and several new psychoactive substances, including mitragynine and cathinones, were the most commonly reported concomitant drugs. ADRs reports in pharmacovigilance databases confirmed the availability of data on the abuse and dependence of prescription opioids and should be considered a resource for monitoring and preventing such issues. Psychiatrists and clinicians prescribing opioids should be aware of their misuse and dependence liability and effects that may accompany their use, especially together with concomitant drugs.

A Focus on Abuse/Misuse and Withdrawal Issues with Selective Serotonin Reuptake Inhibitors (SSRIs): Analysis of Both the European EMA and the US FAERS Pharmacovigilance Databases

Despite increasing reports, antidepressant (AD) misuse and dependence remain underestimated issues, possibly due to limited epidemiological and pharmacovigilance evidence. Thus, here we aimed to determine available pharmacovigilance misuse/abuse/dependence/withdrawal signals relating to the Selective Serotonin Reuptake Inhibitors (SSRI) citalopram, escitalopram, paroxetine, fluoxetine, and sertraline. Both EudraVigilance (EV) and Food and Drug Administration-FDA Adverse Events Reporting System (FAERS) datasets were analysed to identify AD misuse/abuse/dependence/withdrawal issues. A descriptive analysis was performed; moreover, pharmacovigilance measures, including the reporting odds ratio (ROR), the proportional reporting ratio (PRR), the information component (IC), and the empirical Bayesian geometric mean (EBGM) were calculated. Both datasets showed increasing trends of yearly reporting and similar signals regarding abuse and dependence. From the EV, a total of 5335 individual ADR reports were analysed, of which 30% corresponded to paroxetine (n = 1592), 27% citalopram (n = 1419), 22% sertraline (n = 1149), 14% fluoxetine (n = 771), and 8% escitalopram (n = 404). From FAERS, a total of 144,395 individual ADR reports were analysed, of which 27% were related to paroxetine, 27% sertraline, 18% citalopram, 16% fluoxetine, and 13% escitalopram. Comparing SSRIs, the EV misuse/abuse-related ADRs were mostly recorded for citalopram, fluoxetine, and sertraline; conversely, dependence was mostly associated with paroxetine, and withdrawal to escitalopram. Similarly, in the FAERS dataset, dependence/withdrawal-related signals were more frequently reported for paroxetine. Although SSRIs are considered non-addictive pharmacological agents, a range of proper withdrawal symptoms can occur well after discontinuation, especially with paroxetine. Prescribers should be aware of the potential for dependence and withdrawal associated with SSRIs.

The Impact of Regulatory Restrictions on Pregabalin use in Saudi Arabia: An Interrupted Time series Analysis

PURPOSE

The Saudi Food and Drug Authority (SFDA) added pregabalin to the list of controlled substances in December 2017 to minimize the risk of its possible abuse and misuse. This study was aimed at assessing the impact of this decision on the overall use of pregabalin in Saudi Arabia and in comparison, with drugs prescribed to treat neuropathic pain therapy (i.e. vs. gabapentin, tramadol, duloxetine, and amitriptyline).

METHODS

This was an interrupted time-series analysis of the Saudi quarterly sale data of the study drugs from October/2015 to September/2020. These data were obtained from IQVIA and were converted into use estimates (defined daily dose per 1000 inhabitant-days [DDD/TID]). Segmented regression models were conducted to assess the direct (level) and prolonged (trend) changes in use data after the decision. All analyses were completed using RStudio Version 1.4.1103.

RESULTS

Before the SFDA's decision, there was an increased quarter-to-quarter use of pregabalin (DDD/TID: 0.16; 95% confidence interval [CI] 0.04 to 0.28). Pregabalin overall use dropped sharply by -1.85 DDD/TID (95%CI -2.71 to -0.99) directly after the decision with a prolonged quarter-to-quarter declining effect (DDD/TID: -0.22, CI to -0.37 to -0.05). The decision was associated with a direct increase in the use of gabapentin by 0.62 DDD/TID (95%CI 0.52 to 0.72) without any impact on the use of other drugs.

CONCLUSIONS

The results of our study showed that the SFDA decision was associated with a decrease in the overall use of pregabalin, which may help minimize the risk of its abuse and misuse. This article is protected by copyright. All rights reserved.

State-level response to gabapentin misuse in the United States: Implications and future direction

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

Gabapentin misuse is on the rise and has forced many US states to mobilize policies to address this public health concern. The purpose of this manuscript is to update state-level gabapentin misuse-related policies in the US through September 1, 2021, discuss the benefits and risks of current measures, and highlight gaps in national response.

METHODS

Identification of state and federal district policy changes and deliberations related to gabapentin were searched via internet for all 50 states and 1 federal district (n = 51). Only results from state regulatory bodies, such as the board of pharmacy, or state legislative bodies, such as the senate, were considered for inclusion.

RESULTS

Results showed that 22 states and federal districts (43.1%) tightened regulation, while another 2 (3.9%) are considering doing so. Of the 22 states and federal districts with policy changes, 15 (68.2%) enrolled gabapentin into their prescription drug monitoring program, while 7 (31.8%) reclassified gabapentin as a Schedule V controlled substance (C-V).

CONCLUSION

Absent of federal guidance surrounding gabapentin misuse, the onus has fallen on individual states; thus, approaches have ranged from no intervention to reclassification as a C-V. These measures aim to reduce medication supply but fall short of addressing patient outcomes and reducing harm. Therefore, harm reduction-informed public health policies must be implemented to positively impact patient outcomes and enhance safety.

Managing the misuse potential and risk of psychological harm from gabapentinoids in primary care in New Zealand

Gabapentinoid prescribing is increasing in New Zealand. International evidence suggests that this prescribing trend is followed by increasing harms, including misuse, dependence, overdose, and psychological harms including suicidal thoughts or behaviours. However, there is limited guidance for prescribers on how to manage these potential harms. Here, we summarise the current international literature and identify three main risk factors that can be used for screening purposes when considering prescribing a gabapentinoid, to identify patients that may be at greater risk of harm. Based on current knowledge of harms, we provide guidance to prescribers on monitoring patients taking gabapentinoids. Finally, we summarise the evidence regarding tapering, and highlight key knowledge gaps including other interventions, referral, and data from primary care populations.

Post-Marketing Safety Concerns with Esketamine: A Disproportionality Analysis of Spontaneous Reports Submitted to the FDA Adverse Event Reporting System

INTRODUCTION

Esketamine nasal spray received approval for treatment-resistant depression in March 2019.

OBJECTIVE

Using the FDA Adverse Event Reporting System (FAERS) database (March 2019-March 2020), we analysed esketamine-related adverse events (AEs) to detect and characterize relevant safety signals.

METHODS

We used the consolidated case/non-case approach to estimate the reporting odds ratio (ROR) and information component (IC) with relevant confidence intervals (95% CI) for esketamine-related AEs with ≥4 counts. Comparisons between serious and non-serious AEs were performed using non-parametric tests.

RESULTS

The FAERS database contained 962 cases of esketamine-related AEs, with signals detected for several AEs, such as dissociation (ROR = 1,612.64, 95% CI = 1,354.63, 1,919.79; IC = 8.19, 95% CI = 7.96, 8.35), sedation (ROR = 238.46, 95% CI = 202.98, 280.15; IC = 7, 95% CI = 6.75, 7.18), feeling drunk (ROR = 96.17, 95% CI = 61.42, 150.57; IC = 4.84, 95% CI = 4.09, 5.36), suicidal ideation (ROR = 24.03, 95% CI = 18.72, 30.84; IC = 4.31, 95% CI = 3.9, 4.61), and completed suicide (ROR = 5.75, 95% CI = 3.18, 10.41; IC = 2.25, 95% CI = 1.23, 2.94). Signals for suicidal and self-injurious ideation, but not suicide attempt and completed suicide, remained when comparing esketamine to venlafaxine. Females and patients receiving antidepressant polypharmacy, co-medication with mood stabilizers, antipsychotics, benzodiazepines, or somatic medications were more likely to suffer from serious versus non-serious AEs (χ2 = 125.29, p < 0.001, χ2 = 9.08, p = 0.003, χ2 = 8.14, p = 0.004, χ2 = 19.48, p < 0.001, χ2 = 25.62, p < 0.001, and χ2 = 16.79, p < 0.001, respectively).

CONCLUSIONS

Esketamine may carry a clear potential for serious AEs, which deserves urgent clarification by means of further prospective studies.

Application and Clinical Value of Definitive Drug Monitoring in Pain Management and Addiction Medicine

OBJECTIVE

To assess routine application and clinical value of definitive urine drug monitoring (UDM) for drug detection, inconsistent drug use and prescription adherence, along with a comparison to immunoassay screening (IAS).

METHODS

Direct-to-definitive UDM performance was analyzed retrospectively in 5,000 patient specimens. Drug findings, medication inconsistencies and detection sensitivity were assessed, and definitive UDM versus IAS monitoring was studied.

RESULTS

Definitive testing resulted in 18,793 drug findings with 28,403 positive drug and metabolite tests. Definitive testing expanded monitoring with 11,396 drug findings that would not be tested by IAS. The opioids accounted for the highest frequency of inconsistent positive drug-use findings, at 12%. Conversely, inconsistent negative drug findings, used as an index of prescription non-adherence, were determined in 1,751 of 15,409 monitored medications and included a high frequency of antidepressants and antipsychotics inconsistencies. Direct comparison of definitive UDM and IAS showed false-positives by IAS as well as a high rate of false-negatives that would be missed using current confirmation protocols.

CONCLUSIONS

Results from routine application of direct-to-definitive UDM demonstrate the clinical value of drug-use identification and objective evaluation of inconsistencies in drug misuse and medication adherence in pain management and addiction medicine practice. Without conversion to direct-to-definitive UDM, continuing use of IAS will limit the scope of drugs being tested, will result in an indeterminate rate of false negatives and will require confirmation testing to eliminate the reporting of false positive IAS tests. The findings in this study provide evidence-based support for recommended use of a direct-to-definitive drug testing protocol.

The gabapentinoid drugs and their abuse potential

The gabapentinoid drugs, gabapentin and pregabalin, are first-line treatments for neuropathic pain. The epidemics of chronic pain and opioid misuse have given rise to the widespread use of non-opioid drugs such as the gabapentinoids for treatment. Unfortunately, the widespread use of gabapentinoid drugs has resulted in reports of misuse and abuse. Here we summarize the clinical reports of gabapentinoid abuse in different patient populations to help inform clinical practice of chronic pain management.

The Role of Advanced Technologies Supplemented with Traditional Methods in Pharmacovigilance Sciences

BACKGROUND

The immediate automatic systemic monitoring and reporting of adverse drug reactions, improving the efficacy is the utmost need of the medical informatics community. The venturing of advanced digital technologies into the health sector has opened new avenues for rapid monitoring. In recent years, data shared through social media, mobile apps, and other social websites has increased manifolds requiring data mining techniques.

OBJECTIVE

The objective of this report is to highlight the role of advanced technologies together with the traditional methods to proactively aid in the early detection of adverse drug reactions concerned with drug safety and pharmacovigilance.

METHODS

A thorough search was conducted on papers and patents regarding pharmacovigilance. All articles with respect to the relevant subject were explored and mined from public repositories such as Pubmed, Google Scholar, Springer, ScienceDirect (Elsevier), Web of Science, etc. Results: The European Union's Innovative Medicines Initiative WEB-RADR project has emphasized the development of mobile applications and social media data for reporting adverse effects. Only relevant data has to be captured through the data mining algorithms (DMAs) as it plays an important role in timely prediction of risk with high accuracy using two popular approaches; the frequentist and Bayesian approach. Pharmacovigilance at the pre-marketing stage is useful for the prediction of adverse drug reactions in the early developmental stage of a drug. Later, post-marketing safety reports and clinical data reports are important to be monitored through electronic health records, prescription-event monitoring, spontaneous reporting databases, etc. Conclusion: The advanced technologies supplemented with traditional technologies are the need of the hour for evaluating a product's risk profile and reducing risk in population especially with comorbid conditions and on concomitant medications.

Dimethyl Trisulfide Diminishes Traumatic Neuropathic Pain Acting on TRPA1 Receptors in Mice

Pharmacotherapy of neuropathic pain is still challenging. Our earlier work indicated an analgesic effect of dimethyl trisulfide (DMTS), which was mediated by somatostatin released from nociceptor nerve endings acting on SST₄ receptors. Somatostatin release occurred due to TRPA1 ion channel activation. In the present study, we investigated the effect of DMTS in neuropathic pain evoked by partial ligation of the sciatic nerve in mice. Expression of the mRNA of Trpa1 in murine dorsal-root-ganglion neurons was detected by RNAscope. Involvement of TRPA1 ion channels and SST₄ receptors was tested with gene-deleted animals. Macrophage activity at the site of the nerve lesion was determined by lucigenin bioluminescence. Density and activation of microglia in the spinal cord dorsal horn was verified by immunohistochemistry and image analysis. Trpa1 mRNA is expressed in peptidergic and non-peptidergic neurons in the dorsal root ganglion. DMTS ameliorated neuropathic pain in Trpa1 and Sstr4 WT mice, but not in KO ones. DMTS had no effect on macrophage activity around the damaged nerve. Microglial density in the dorsal horn was reduced by DMTS independently from TRPA1. No effect on microglial activation was detected. DMTS might offer a novel therapeutic opportunity in the complementary treatment of neuropathic pain.

[Pharmacotherapy of alcohol withdrawal: update and new developments]

Bislang sind nur wenige Medikamente zur pharmakologischen Rückfallprophylaxe der Alkoholabhängigkeit zugelassen. Neben dem in Deutschland nicht mehr vertriebenen Disulfiram sind es die Opioidantagonisten Naltrexon und Nalmefen sowie das vermutlich über glutamaterge Neurone wirkende Acamprosat. Baclofen und γ‑Hydroxybutyrat (GHB) sind in einzelnen Ländern zugelassen. Wirkstoffe wie z. B. Vareniclin, Gabapentin und Topiramat können für die Rückfallprophylaxe der Alkoholabhängigkeit von Interesse sein, jedoch ist bislang keine Zulassung erfolgt. Vor dem Hintergrund der zur Revision anstehenden S3-Leitlinie zur Diagnose und Behandlung alkoholbezogener Störungen wird der heutige Kenntnisstand zur Pharmakotherapie der Alkoholabhängigkeit dargestellt.

Characterization of gabapentin use in Kentucky after reclassification as a Schedule V controlled substance

BACKGROUND

Owing to increasing concern over the potential for gabapentin misuse, gabapentin was reclassified as a schedule V controlled substance in Kentucky (July 2017).

OBJECTIVE

This study aimed to characterize gabapentin use among Kentucky residents in the first year after its scheduling.

METHODS

This study used Kentucky All Schedule Prescription Electronic Reporting data (2018). Gabapentin use was defined as having at least 1 dispensed gabapentin prescription, and high-dose gabapentin use was defined as an average daily dose of more than 3600 mg at the patient level. The prevalence of gabapentin use, concurrent use of gabapentin with opioid analgesics (OAs) (gabapentin-OA), and gabapentin with OAs and benzodiazepines (BDZs) (gabapentin-OA-BDZ) were assessed. Estimated prevalence rate ratio and its 95% CI were reported to compare gabapentin use rates across different demographic groups.

RESULTS

A total of 16% of all 2018 controlled substance prescriptions were for gabapentin, and approximately 20% of Kentucky residents with controlled substance prescriptions received gabapentin at least once in 2018. The overall prevalence of gabapentin use was 63 per 1000 residents, with the highest rates among residents aged 55-64 years (126.9 per 1000). The prevalence of gabapentin use was higher in females (74.6 per 1000) versus males (50.6 per 1000) and in residents living in the Appalachian region (88.57 per 1000) versus Central (51.78 per 1000) and Delta (66.41 per 1000) regions. Among gabapentin users, 1% were high-dose users; 27.4% and 11.9% received gabapentin-OA or gabapentin-OA-BDZ concurrently, respectively. As the average daily dose increased from less than 900 mg to high-dose, the percentage of concurrent gabapentin-OA use increased from 13.4% to 50.7%.

CONCLUSION

Gabapentin is widely prescribed in Kentucky, with higher rates of use observed in females, those older than 55 years and individuals living in the Appalachian region. Concurrent use of gabapentin and OAs is common, especially in those receiving high-dose gabapentin. Future studies are needed to assess the risks associated with gabapentin use.

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.

Factors Associated with Gabapentin Misuse among People Who Inject Drugs in Appalachian Kentucky

Gabapentin is misused to potentiate the euphoric effects of opioids, self-treat physical pain, and moderate opioid withdrawal symptoms. Because examinations of gabapentin misuse among people who inject drugs (PWID) are scant, the aim of this study is to identify factors associated with gabapentin misuse among this population. Methods: Data are drawn from a study examining the uptake of syringe service programs (SSPs) in Appalachian Kentucky. The sample includes 324 PWID who were age 18 and over and reported past month drug injection. Logistic regression models were constructed to examine recent (past 90 days) gabapentin misuse. Results: Participants are female (50.0%); Hispanic (2.2%), Black (1.5%), white (90.7%), and other race/ethnicity (4.6%). Mean age is 37. Participants reporting gabapentin misuse had higher odds of reporting (mis)use of marijuana, cocaine, methamphetamine, prescription opioids, benzodiazepines, prescription stimulants, fentanyl, and buprenorphine (p < .042); severe substance use disorder (p < .000); and recent physical pain (p < .003). In multivariable models, findings related to misuse of prescription opioids and buprenorphine; severe substance use disorder; and recent physical pain or discomfort, remained significant (p < .042). Conclusions: This is one of the first studies to examine gabapentin misuse among PWID. It is possible that individuals reporting recent gabapentin misuse are attempting to self-treat physical pain when healthcare is limited. Gabapentin may also be misused to achieve desired central nervous system effects and to potentiate opioid highs. Syringe service programs can educate PWID about the potential dangers of polydrug use involving gabapentin and to connect PWID with needed healthcare services.