Use of Gabapentin in the Treatment of Substance Use and Psychiatric Disorders: A Systematic Review

Loss of Sigma-2 Receptor/TMEM97 Is Associated with Neuropathic Injury-Induced Depression-Like Behaviors in Female Mice

Previous studies have shown that ligands that bind to sigma-2 receptor/TMEM97 (s2R/TMEM97), a transmembrane protein, have anxiolytic/antidepressant-like properties and relieve neuropathic pain-like effects in rodents. Despite medical interest in s2R/TMEM97, little affective and pain behavioral characterization has been done using transgenic mice, which limits the development of s2R/TMEM97 as a viable therapeutic target. Using wild-type (WT) and global Tmem97 knock-out (KO) mice, we sought to identify the contribution of Tmem97 in modulating affective and pain-like behaviors using a battery of affective and pain assays, including open field, light/dark preference, elevated plus maze, forced swim test, tail suspension test, and the mechanical sensitivity tests. Our results demonstrate that female Tmem97 KO mice show less anxiety-like and depressive-like behaviors in light/dark preference and tail suspension tests but not in an open field, elevated plus maze, and forced swim tests at baseline. We next performed spared nerve injury in WT and Tmem97 KO mice to assess the role of Tmem97 in neuropathic pain-induced anxiety and depression. WT mice, but not Tmem97 KO mice, developed a prolonged neuropathic pain-induced depressive-like phenotype when tested 10 weeks after nerve injury in females. Our results show that Tmem97 plays a role in modulating anxiety-like and depressive-like behaviors in naive animals with a significant change in the presence of nerve injury in female mice. Overall, these data demonstrate that Tmem97 could be a target to alleviate affective comorbidities of pain disorders.

Considerations and limitations of buprenorphine prescribing for opioid use disorder in the intensive care unit setting: A narrative review

PURPOSE

The purpose of this review is to discuss important considerations when prescribing buprenorphine for opioid use disorder (OUD) in the intensive care unit (ICU) setting, recognizing the challenges of providing detailed recommendations in the setting of limited available evidence.

SUMMARY

Buprenorphine is a partial mu-opioid receptor agonist that is likely to be increasingly prescribed for OUD in the ICU setting due to the relaxation of prescribing regulations. The pharmacology and pharmacokinetics of buprenorphine are complicated by the availability of several formulations that can be given by different administration routes. There is no single optimal dosing strategy for buprenorphine induction, with regimens ranging from very low-dose to high dose regimens. Faster induction with higher doses of buprenorphine has been studied and is frequently utilized in the emergency department. In patients admitted to the ICU who were receiving opioids either medically or illicitly, analgesia will not occur until their baseline opioid requirements are covered when their preadmission opioid is either reversed or interrupted. For patients in the ICU who are not on buprenorphine at the time of admission but have possible OUD, there are no validated tools to diagnose OUD or the severity of opioid withdrawal in critically ill patients unable to provide the subjective components of instruments validated in outpatient settings. When prescribing buprenorphine in the ICU, important issues to consider include dosing, monitoring, pain management, use of adjunctive medications, and considerations to transition to outpatient therapy. Ideally, addiction and pain management specialists would be available when buprenorphine is prescribed for critically ill patients.

CONCLUSION

There are unique challenges when prescribing buprenorphine for OUD in critically ill patients, regardless of whether they were receiving buprenorphine when admitted to the ICU setting for OUD or are under consideration for buprenorphine initiation. There is a critical need for more research in this area.

Management of Critically Ill Patients Receiving Medications for Opioid Use Disorder

TOPIC IMPORTANCE

Critical care clinicians are likely to see an increasing number of patients admitted to the ICU who are receiving US Food and Drug Administration-approved medications for opioid use disorder (MOUDs) given the well-documented benefits of these agents. Oral methadone, multiple formulations of buprenorphine, and extended-release naltrexone are the three types of MOUD most likely to be encountered by ICU clinicians; however, these drugs vary with respect to formulations, pharmacokinetics, and adverse effects.

REVIEW FINDINGS

No published clinical practice guidelines or consensus statements are available to guide decision-making in patients admitted to the ICU setting who are receiving MOUDs before admission. Additionally, no randomized trials and limited observational studies have evaluated issues related to MOUD use in the ICU. Therefore, ICU clinicians caring for patients admitted who are taking MOUDs must base their decision-making on data extrapolation from pharmacokinetic, pharmacologic, and clinical studies performed in non-ICU settings.

SUMMARY

Despite the challenges in administering MOUDs in critically ill patients, extrapolation of data from other hospital settings suggests that the benefits of continuing MOUD therapy outweigh the risks in patients able to continue therapy. This article provides guidance for critical care clinicians caring for patients admitted to the ICU already receiving methadone, buprenorphine, or extended-release naltrexone. The guidance includes algorithms to aid clinicians in the clinical decision-making process, recognizing the inherent limitations of the existing evidence on which the algorithms are based and the need to account for patient-specific considerations.

Prediction of adverse events risk in patients with comorbid post-traumatic stress disorder and alcohol use disorder using electronic medical records by deep learning models

BACKGROUND

Identifying co-occurring mental disorders and elevated risk is vital for optimization of healthcare processes. In this study, we will use DeepBiomarker2, an updated version of our deep learning model to predict the adverse events among patients with comorbid post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD), a high-risk population.

METHODS

We analyzed electronic medical records of 5565 patients from University of Pittsburgh Medical Center to predict adverse events (opioid use disorder, suicide related events, depression, and death) within 3 months at any encounter after the diagnosis of PTSD+AUD by using DeepBiomarker2. We integrated multimodal information including: lab tests, medications, co-morbidities, individual and neighborhood level social determinants of health (SDoH), psychotherapy and veteran data.

RESULTS

DeepBiomarker2 achieved an area under the receiver operator curve (AUROC) of 0.94 on the prediction of adverse events among those PTSD+AUD patients. Medications such as vilazodone, dronabinol, tenofovir, suvorexant, modafinil, and lamivudine showed potential for risk reduction. SDoH parameters such as cognitive behavioral therapy and trauma focused psychotherapy lowered risk while active veteran status, income segregation, limited access to parks and greenery, low Gini index, limited English-speaking capacity, and younger patients increased risk.

CONCLUSIONS

Our improved version of DeepBiomarker2 demonstrated its capability of predicting multiple adverse event risk with high accuracy and identifying potential risk and beneficial factors.

Gabapentin Use Among Individuals Initiating Buprenorphine Treatment for Opioid Use Disorder

Importance

Gabapentin prescriptions have drastically increased in the US due to off-label prescribing in settings such as opioid use disorder (OUD) treatment to manage a range of comorbid conditions and withdrawal symptoms, despite a lack of evidence.

Objective

To assess the purpose and associated risks of off-label gabapentin use in OUD treatment.

Design, Setting, and Participants

This retrospective recurrent-event case-control study with a crossover design used administrative claims data from MarketScan Commercial and Multi-State Medicaid databases from January 1, 2006, to December 31, 2016. Individuals aged 12 to 64 years with an OUD diagnosis and filling buprenorphine prescriptions were included in the primary analysis conducted from July 1, 2022, through June 1, 2023. Unit of observation was the person-day.

Exposures

Days covered by filled gabapentin prescriptions.

Main Outcomes and Measures

Primary outcomes were receipt of gabapentin in the 90 days after initiation of buprenorphine treatment and drug-related poisoning. Drug-related poisonings were defined using codes from International Classification of Diseases, Ninth Revision, and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision.

Results

A total of 109 407 patients were included in the analysis (mean [SD] age, 34.0 [11.2] years; 60 112 [54.9%] male). Among the 29 967 patients with Medicaid coverage, 299 (1.0%) were Hispanic, 1330 (4.4%) were non-Hispanic Black, 23 112 (77.1%) were non-Hispanic White, and 3399 (11.3%) were other. Gabapentin was significantly less likely to be prescribed to Black or Hispanic patients, and more likely to be prescribed to female patients, those with co-occurring substance use or mood disorders, and those with comorbid physical conditions such as neuropathic pain. Nearly one-third of persons who received gabapentin (4336 [31.1%]) had at least 1 drug-related poisoning after initiating buprenorphine treatment, compared with 13 856 (14.5%) among persons who did not receive gabapentin. Adjusted analyses showed that days of gabapentin use were not associated with hospitalization for drug-related poisoning (odds ratio, 0.98 [95% CI, 0.85-1.13]). Drug-related poisoning risks did not vary based on dosage.

Conclusions and Relevance

Gabapentin is prescribed in the context of a myriad of comorbid conditions. Even though persons receiving gabapentin are more likely to have admissions for drug-related poisoning, these data suggest that gabapentin is not associated with an increased risk of drug-related poisoning alongside buprenorphine in adjusted analyses. More data on the safety profile of gabapentin in OUD settings are needed.

Developing non-opioid therapeutics to alleviate pain among persons with opioid use disorder: a review of the human evidence

The opioid crisis remains a major public health concern, causing significant morbidity and mortality worldwide. Pain is frequently observed among individuals with opioid use disorder (OUD), and the current opioid agonist therapies (OAT) have limited efficacy in addressing the pain needs of this population. We reviewed the most promising non-opioid analgesic therapies for opioid-dependent individuals synthesising data from randomised controlled trials in the Medline database from December 2022 to March 2023. Ketamine, gabapentin, serotoninergic antidepressants, and GABAergic drugs were found to be the most extensively studied non-opioid analgesics with positive results. Additionally, we explored the potential of cannabinoids, glial activation inhibitors, psychedelics, cholecystokinin antagonists, alpha-2 adrenergic agonists, and cholinergic drugs. Methodological improvements are required to advance the development of novel analgesic strategies and establish their safety profile for opioid-dependent populations. We highlight the need for greater integration of experimental pain methods and abuse liability assessments, more granular assessments of prior opioid exposure, greater uniformity of pain types within study samples, and a particular focus on individuals with OUD receiving OAT. Finally, future research should investigate pharmacokinetic interactions between OAT and various non-opioid analgesics and perform reverse translation basic experiments, particularly with methadone and buprenorphine, which remain the standard OUD treatment.

Pregabalin Dependence and Management in a 55-Year-Old Female with Chronic Low Back Pain

This case report explores the complexities of managing chronic pain and the subsequent development of pregabalin dependence in a 55-year-old female patient with a prior history of vertebral fracture. Over a period of 10 years, the patient relied on a combination of Aceclofenac and pregabalin to alleviate her pain. An alternative treatment approach was implemented, involving adjustments to medication dosages and gradual tapering. Throughout the treatment process, interdisciplinary collaboration played a pivotal role in addressing unexpected symptoms such as facial movements and neck swelling. This case report highlights the significance of recognizing and addressing pregabalin dependence in patients with chronic pain.

Gabapentinoid Prescribing Practices at a Large Academic Medical Center

Objective

To evaluate indications for gabapentinoid prescription at an academic medical center.

Patients and Methods

We retrospectively reviewed patients aged 18 years or older who were prescribed gabapentinoids (gabapentin or pregabalin) during the 2019 calendar year at an academic medical center in the US Midwest. Patient demographic characteristics, indications for gabapentinoid prescription, and prescribing clinician specialities were abstracted from a random sample, and the findings were extrapolated to the overall cohort.

Results

A total of 6205 prescriptions for gabapentinoids were initially identified. In the random sample of prescriptions (n=721), 89.5% were for gabapentin and 10.5% were for pregabalin. More women than men were prescribed gabapentinoids, and the mean ± SD patient age was 58.6±16.9 years. The top 5 indications for gabapentinoid prescriptions were neuropathic pain, musculoskeletal pain, restless legs syndrome, anxiety, and headache. A majority (66.7%) of prescriptions had substantial-to-modest evidence, but 29.0% of prescriptions had conflicting or insufficient evidence.

Conclusion

To our knowledge, this study is one of the first to manually review clinical notes from multiple clinical specialities to ascertain indications for gabapentinoid prescriptions. Although most prescriptions had modest evidence to support their use, a high percentage of gabapentinoid prescriptions were issued for indications not supported by robust evidence. This suggests that prescribers are gravitating toward gabapentinoid use for reasons that are currently not fully understood. Clinician intent for off-label gabapentinoid prescriptions at the point of care should be further studied to understand the factors that lead to these clinical decisions.

The Role of Gabapentinoids in the Substance Use Pattern of Adult Germans Seeking Inpatient Detoxification Treatment - A Pilot Study

To shed more light on the addictive power of the gabapentinoids (GPTs) gabapentin and pregabalin, we performed a structured face-to-face interview with GPT-users about DSM-IV-dependence-criteria (sedatives), consume-motives and cessation-needs. Among 100 patients consecutively admitted to a detoxification-ward, fifteen (15%) reported lifetime GPT-use (18-50 years old, 2 females): seven (7%) used gabapentin, twelve (12%) pregabalin and four had lifetime experiences with both GPTs. Of the seven gabapentin-users, three patients were dependent including one person with a spontaneous remission. Of the 12 pregabalin-users, five were dependent, including two persons with a spontaneous remission. Fourteen of fifteen cases reported GPT-use side-by-side with an opioid-use, mostly for sparing opioids. Twelve GPT-users additionally co-used benzodiazepines. In no case, a GPT was the reason for detoxification treatment or reported to be involved in an emergency event. Altogether, every 7^th patient (n = 15) of our inpatient detoxification-seeking sample reported GPT-use including 50% (n = 8) who were dependent. Among them, 35% (3/8) had been already spontaneously remitted. As GPT-users reported no cession-need and the vast majority were primarily affected by co-occurring opioid- and benzodiazepine-addiction, we assume that GPTs more likely played a bystander-role than mediating the addictive behavior of this population with multiple recreational drug use experience.

Understanding motivations and use typologies of gabapentin with opioid agonist medications

BACKGROUND

Prior research suggests a potential relationship between the nonmedical use of gabapentin and use of opioid agonist medications (OAMs), buprenorphine and methadone. However, this research has been limited in scope and understanding despite increases in gabapentin prescribing in opioid use disorder (OUD) treatment settings and increased detection in opioid overdose fatalities.

METHODS

Data were analyzed for 346 participants of a follow-up program to an ongoing national opioid surveillance program of new entrants to treatment for opioid use disorder. Data were sourced from a cross-sectional online survey distributed in July/August 2021.

RESULTS

Lifetime exposure to gabapentin was reported by 60.0 % of the sample, while lifetime history of nonmedical use was reported by 43.2 %. Of those nonmedically using gabapentin, 50.0 % did so while also on a dosage of either buprenorphine or methadone, with 28.4 % engaged in concurrent nonmedical use of both gabapentin and OATs. Motivations for concurrent nonmedical use included high-seeking (38.6 %), self-management of pain/physical symptoms (33.3 %), and self-management of OUD (22.2 %).

CONCLUSIONS

Gabapentin exposure in treatment-seeking persons with OUD appears to be quite common, and use, both medically and nonmedically, frequently occurs alongside OAMs. Motivations for concurrent nonmedical use of gabapentin and OATs mirrors motivations for off-label prescribing by healthcare providers, but may also serve as a form of self-management of OUD when OAM regimens are interrupted, insufficiently prescribed or prescribed at insufficient dosages. Further research should seek to understand the risks versus benefits of gabapentin in OAM treatment settings.

Helpful or Harmful? The Therapeutic Potential of Medications with Varying Degrees of Abuse Liability in the Treatment of Substance Use Disorders

Purpose of Review

This review summarizes recent clinical trial research on pharmacological treatments for substance use disorders, with a specific focus on agents with potential abuse liability.

Recent Findings

Pharmacological treatments for substance use disorders may include gabapentinoids, baclofen, modafinil, ketamine, cannabinoids, gamma-hydroxybutyrate, and psychedelics. Gabapentinoids may decrease negative subjective effects of withdrawal in alcohol and cannabis use disorders. Cannabinoids similarly appear to decrease use and withdrawal symptoms in cannabis use disorder, while research shows stimulant medications may reduce cravings and increase abstinence in cocaine use disorder. Ketamine and psychedelics may help treat multiple substance use disorders. Ketamine may reduce withdrawal symptoms, promote abstinence, and diminish cravings in alcohol and cocaine use disorders and psychedelics may promote remission, decrease use, and reduce cravings in alcohol and opioid use disorders.

Summary

Regardless of current regulatory approval statuses and potentials for abuse, multiple agents should not be dismissed prematurely as possible treatments for substance use disorders. However, further clinical research is needed before effective implementation can begin in practice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40429-022-00432-9.

Breaking Mental Barriers Promotes Recovery After Spinal Cord Injury

Functional recovery after spinal cord injury (SCI) often proves difficult as physical and mental barriers bar survivors from enacting their designated rehabilitation programs. We recently demonstrated that adult mice administered gabapentinoids, clinically approved drugs prescribed to mitigate chronic neuropathic pain, recovered upper extremity function following cervical SCI. Given that rehabilitative training enhances neuronal plasticity and promotes motor recovery, we hypothesized that the combination of an aerobic-based rehabilitation regimen like treadmill training with gabapentin (GBP) administration will maximize recovery in SCI mice by strengthening synaptic connections along the sensorimotor axis. Whereas mice administered GBP recovered forelimb functions over the course of weeks and months following SCI, no additive forelimb recovery as the result of voluntary treadmill training was noted in these mice. To our surprise, we also failed to find an additive effect in mice administered vehicle. As motivation is crucial in rehabilitation interventions, we scored active engagement toward the rehabilitation protocol and found that mice administered GBP were consistently participating in the rehabilitation program. In contrast, mice administered vehicle exhibited a steep decline in participation, especially at chronic time points. Whereas neuroinflammatory gene expression profiles were comparable between experimental conditions, we discovered that mice administered GBP had increased hippocampal neurogenesis and exhibited less anxiety-like behavior after SCI. We also found that an external, social motivator effectively rescues participation in mice administered vehicle and promotes forelimb recovery after chronic SCI. Thus, not only does a clinically relevant treatment strategy preclude the deterioration of mental health after chronic SCI, but group intervention strategies may prove to be physically and emotionally beneficial for SCI individuals.

Sustained drug delivery strategies for treatment of common substance use disorders: Promises and challenges

Substance use disorders (SUDs) are a leading cause of death and other ill health effects in the United States and other countries in the world. Several approaches ranging from detoxification, behavioral therapy, and the use of antagonists or drugs with counter effects are currently being applied for its management. Amongst these, drug therapy is the mainstay for some drug abuse incidences, as is in place specifically for opioid abuse or alcohol dependence. The severity of the havocs observed with the SUDs has triggered constant interest in the discovery and development of novel medications as well as suitable or most appropriate methods for the delivery of these agents. The chronic need of such drugs in users warrants the need for their prolonged or sustained systemic availability. Further, the need to improve patient tolerance to medication, limit invasive drug use and overall treatment outcome are pertinent considerations for embracing sustained release designs for medications used in managing SUDs. This review aims to provide an overview on up-to-date advances made with regards to sustained delivery systems for the drugs for treatment of different types of SUDs such as opioid, alcohol, tobacco, cocaine, and cannabis use disorders. The clinical relevance, promises and the limitations of deployed sustained release approaches along with future opportunities are discussed.

Psychiatric Uses of Gabapentin

OBJECTIVE

This article reviews evidence-based psychiatric uses of gabapentin, along with associated risks.

METHOD OF RESEARCH

An extensive literature review was conducted, primarily of articles searchable in PubMed, relating to psychiatric uses, safety, and adverse effects of gabapentin.

RESULTS

Evidence supports gabapentin as a treatment for alcohol withdrawal and alcohol use disorder. There is sufficient evidence to consider gabapentin as a third-line treatment for social anxiety disorder and severe panic disorder. Evidence does not support the use of gabapentin for bipolar disorder, major depressive disorder (MDD), posttraumatic stress disorder (PTSD), obsessive compulsive disorder (OCD), stimulant use disorder, or opioid withdrawal. Risks of gabapentin use are highest among those with a history of a substance use disorder and those concurrently taking opioids.

CONCLUSION

While gabapentin has a place in psychiatry for a select few indications, the literature does not support its use for many studied diagnoses.

Association between gabapentinoids and oedema treated with loop-diuretics: a pooled sequence symmetry analysis from the United States and Denmark

AIMS

To assess the gabapentinoid-oedema-loop diuretic prescribing cascade in adults using large administrative health care databases from the US and Denmark.

METHODS

This study used a sequence symmetry analysis to assess loop diuretic initiation before and after the initiation of gabapentinoids among patients aged 20 years or older without heart failure or chronic kidney disease. Data from MarketScan Commercial and Medicare Supplemental Claims databases (2005 to 2019) and Danish National Prescription Register (2005 to 2018) were analyzed. Use of loop diuretics associated with initiation of selective norepinephrine reuptake inhibitors (SNRI) was used as a negative control. We assessed the pooled temporality of loop diuretic initiation relative to gabapentinoid or SNRI initiation across the two countries. Secular trend-adjusted sequence ratios (aSRs) with 95% Cis were calculated using data from 90 days before and after initiation of gabapentinoids. Pooled ratio of aSRs were calculated by comparing gabapentinoids to SNRIs.

RESULTS

Among the 1,511,493 gabapentinoid initiators (Denmark [n=338,941]; United States [n=1,172,552]), 20,139 patients had a new loop diuretic prescription 90 days before or after gabapentinoid initiation, resulting in a pooled aSR of 1.33 (95% CI 1.06-1.67). The pooled aSR for the negative control (i.e., SNRI) was 0.84 (95% CI 0.75-0.94), which resulted in a pooled ratio of aSRs of 1.58 (95% CI 1.23-2.04). Pooled estimated incidence of the gabapentinoid-loop diuretic prescribing cascade was 8.14 (95% CI, 1.92-34.49) events per 1000 patient years.

CONCLUSION

We identified evidence of the gabapentinoid-oedema-loop diuretic prescribing cascade in two countries.

Adverse outcomes associated with concurrent gabapentin, opioid, and benzodiazepine utilization: A nested case-control study

Background

Gabapentin, opioids, and/or benzodiazepines are commonly prescribed for a variety of pain and psychiatric conditions. Despite the high likelihood of co-prescription of these medications, little is known about co-utilization of gabapentin (GABA), opioids (OP), and benzodiazepines (BZD) and associated public health outcomes.

Methods

Using Medicare CCW Data, 2013-2016, we conducted a nested case-control study to examine the association between concurrent utilization of GABA, OP, and BZD and respiratory depression, opioid, and substance-related overdose among Medicare disabled beneficiaries. Cases and controls were Fee-for-service disabled beneficiaries who had a diagnosis of acute pain (AP), chronic pain (CP) or mental health conditions (MH) and received GABA, OP or BZD. Cases with respiratory depression, opioid or substance-related overdose were matched with up to 4 controls on socio-demographics, year of cohort entry and disease risk score. Primary exposure was concurrent medication utilization defined as an overlap of at least one day in prescriptions for GABA, OP and BZD.

Findings

Across all cohorts, the majority of cases and controls were under 65, female, dually eligible and had prior histories of pain and mental health conditions. GABA+OP+BZD use was associated with increased odds of respiratory depression [AOR(95%CI)-AP: 1.35 (1.19-1.52), CP:1.24 (1.11-1.38) and MH: 1.16 (1.02-1.32) vs. OP only], opioid-related overdose [AP: 1.43 (1.04-1.98), CP: 1.47 (1.07-2.00) and MH: 1.44 (1.04-2.00) vs. OP only], and substance-related overdose [AP: 1.77 (1.26-2.50), CP: 1.70 (1.24-2.34) and MH: 1.92 (1.31-2.82) vs. GABA only]. While there were cohort differences in the association between GABA+OP and both respiratory depression and opioid-related overdose, GABA+OP and GABA+BZD use were associated with significantly higher odds of substance-related overdose across all clinical cohorts.

Interpretation

Among Medicare disabled beneficiaries, concurrent utilization of gabapentin, opioids, and benzodiazepines is associated with multiple adverse outcomes. Given this, it is imperative that the benefits and risks of co-prescribing these medications be comprehensively examined.

Funding

None.

Analgesic Efficacy of Gabapentin and Pregabalin in Patients Undergoing Laparoscopic Bariatric Surgeries: a Systematic Review and Meta-analysis

This meta-analysis investigated the effect of oral gabapentinoids (i.e., pregabalin and gabapentin) on analgesic consumption (i.e., primary outcome) and pain relief (i.e., secondary outcome) in patients following bariatric surgery. Analysis of five eligible trials published between 2010 and 2019 including 363 participants receiving gabapentinoids revealed a significantly lower morphine consumption [mean difference (MD) =  - 15.1 mg, p = 0.004; evidence certainty: low] and risk of nausea/vomiting [risk ratio (RR) = 0.49, p = 0.002; evidence certainty: high] at postoperative 6-24 h. There was also a lower pain score at postoperative 0-4 h (MD =  - 1.41, p < 0.00001; evidence certainty: low) and 6-12 h (MD =  - 0.9, p = 0.007; evidence certainty: low) compared with controls, while pain severity at postoperative 24 h was comparable between two groups. In summary, preoperative oral gabapentinoids optimized postoperative pain outcomes and reduced risk of nausea/vomiting following bariatric surgery.

How prevalent and severe is addiction on GABAmimetic drugs in an elderly German general hospital population? Focus on gabapentinoids, benzodiazepines, and z-hypnotic drugs

OBJECTIVE

Gabapentinoids (GPT) are reported to be increasingly misused by opioid- and polydrug-users, but the addictive potential of GPT outside of these populations remains understudied. Investigations comparing GPT abuse and dependence liability to that of other commonly prescribed Central Nervous System-acting medications are therefore warranted. We provide a comparison of GPT-abuse/dependence to that of other GABAmimetics within an elderly population.

DESIGN

DSM-IV-TR-based data (previously prospectively collected by SKID-I-interview) from a random sample of elderly patients admitted to a metropolitan German general hospital were reviewed. The prevalence and severity of GPT, benzodiazepine (BDZ), and z-hypnotic drug (ZD)-abuse and -dependence were compared, stratified also by mono-substance (no concurrent current or previous substance use) and de novo-substance (first)-abuse and -dependence states.

RESULTS

Among 400 patients (75 ± 6.4 years old; 63% females), neither current nor past abuse of BDZ, ZD or GPT, nor other illicit substances was observed. Dependence upon BDZ, ZD or GPT was observed among 55 (13.75%) individuals. The related lifetime/12-month prevalence-rates were: dependence condition (BDZ: 7%/2.45%; ZD: 4.25%/4.25%; GPT: 2.75/2.5%); mono-dependence condition (BDZ: 2.25%/0.75%; ZD: 1%/1%, GPT: 0%/0%); de novo-dependence condition (BDZ: 2.75%/1.75%; ZD: 1%/1%, GPT: 0.5%/0.5%). Opioid analgesic-dependence (N = 43/400) was significantly more frequently linked with BDZ than with GPT (p < 0.01) [Correction added on 29 December 2021, after first online publication: In the sentence 'Opioid analgesic-dependence…', the term 'and ZD' has been deleted]. For all three GABAmimetic classes, most mono- and de novo-dependence states were mild-to-moderate and lasted 2-6 years (median).

CONCLUSION

GABAmimetic-dependence was usually mixed with other substance-dependences. Every third to fourth instance of BDZ- or ZD-dependence was a mono-dependence condition, while a pure GPT-dependence was absent in this elderly (and illicit substance-naïve) population.

Peptide LCGA-17 Attenuates Behavioral and Neurochemical Deficits in Rodent Models of PTSD and Depression

We have previously described the LCGA-17 peptide as a novel anxiolytic and antidepressant candidate that acts through the α2δ VGCC (voltage-gated calcium channel) subunit with putative synergism with GABA-A receptors. The current study tested the potential efficacy of acute and chronic intranasal (i.n.) LCGA-17 (0.05 mg/kg and 0.5 mg/kg) in rats on predator odor-induced conditioned place aversion (POCPA), a model of post-traumatic stress disorder (PTSD), and chronic unpredictable stress (CUS) that produce a range of behavioral and physiological changes that parallel symptoms of depression in humans. CUS and LCGA-17 treatment effects were tested in the sucrose preference (SPT) social interaction (SI), female urine sniffing (FUST), novelty-suppressed feeding (NSFT), and forced swim (FST) tests. Analysis of the catecholamines content in brain structures after CUS was carried out using HPLC. The efficacy of i.n. LCGA-17 was also assessed using the Elevated plus-maze (EPM) and FST. Acute LCGA-17 administration showed anxiolytic and antidepressant effects in EPM and FST, similar to diazepam and ketamine, respectively. In the POCPA study, LCGA-17 significantly reduced place aversion, with efficacy greater than doxazosin. After CUS, chronic LCGA-17 administration reversed stress-induced alterations in numerous behavioral tests (SI, FUST, SPT, and FST), producing significant anxiolytic and antidepressant effects. Finally, LCGA-17 restored the norepinephrine levels in the hippocampus following stress. Together, these results support the further development of the LCGA-17 peptide as a rapid-acting anxiolytic and antidepressant.

Gabapentin and pregabalin in bipolar disorder, anxiety states, and insomnia: Systematic review, meta-analysis, and rationale

The gabapentinoids, gabapentin, and pregabalin, target the α₂δ subunits of voltage-gated calcium channels. Initially licensed for pain and seizures, they have become widely prescribed drugs. Many of these uses are off-label for psychiatric indications, and there is increasing concern about their safety, so it is particularly important to have good evidence to justify this usage. We conducted a systematic review and meta-analysis of the evidence for three of their common psychiatric uses: bipolar disorder, anxiety, and insomnia. Fifty-five double-blind randomised controlled trials (RCTs) and 15 open-label studies were identified. For bipolar disorder, four double-blind RCTs investigating gabapentin, and no double-blind RCTs investigating pregabalin, were identified. A quantitative synthesis could not be performed due to heterogeneity in the study population, design and outcome measures. Across the anxiety spectrum, a consistent but not universal effect in favour of gabapentinoids compared to placebo was seen (standardised mean difference [SMD] ranging between -2.25 and -0.25). Notably, pregabalin (SMD -0.55, 95% CI -0.92 to -0.18) and gabapentin (SMD -0.92, 95% CI -1.32 to -0.52) were more effective than placebo in reducing preoperative anxiety. In insomnia, results were inconclusive. We conclude that there is moderate evidence of the efficacy of gabapentinoids in anxiety states, but minimal evidence in bipolar disorder and insomnia and they should be used for these disorders only with strong justification. This recommendation applies despite the attractive pharmacological and genetic rationale for targeting voltage-gated calcium channels.

Patterns of opioid and benzodiazepine use with gabapentin among disabled Medicare beneficiaries - A retrospective cohort study

BACKGROUND

Our goal was to describe specific patterns associated with co-prescriptions of gabapentin, opioids, and benzodiazepines among disabled Medicare beneficiaries.

METHODS

Using 2013-2015 Medicare data, we conducted a retrospective cohort study among fee-for-service disabled beneficiaries continuously enrolled in Medicare Parts A, B, and D. The index date was defined as the earliest fill date for a gabapentin, opioid, or benzodiazepine prescription. Monotherapy, dual therapy, and tri-therapy were defined as utilization of one, two, and three medication classes, respectively. Augmentation was defined as a prescription for a different medication class in addition to prescription for initial medication; switching referred to a change in prescription for a different medication class with no subsequent fills of initial medication. We used descriptive statistics, Kaplan Meier analyses and Cox proportional hazards to examine the association between initial therapy and monotherapy, dual therapy, tri-therapy, switching and augmentation.

RESULTS

Among 151,552 disabled beneficiaries, gabapentin initiators were more likely to augment therapy (50.1%) when compared to opioid (28.7%) and benzodiazepine (38.7%) users. When compared to opioid initiators, the risk of augmentation (HR[95%CI]: 1.85[1.82-1.89]) and switching (1.62 [1.51-1.73]) was significantly higher among gabapentin initiators. Risk of augmentation was also significantly higher among beneficiaries with co-morbid pain and mental health conditions (p < 0.01). Overall, the majority of beneficiaries augmented and switched within 2-months and 4-months after initiating therapy, respectively.

CONCLUSIONS

Given safety concerns associated with gabapentin, opioids, and benzodiazepines, it is imperative that the benefits and risks of co-prescribing these medications be examined comprehensively, especially for those in vulnerable sub-groups.

Results from a randomized, double-blind, placebo-controlled, crossover, multimodal-MRI pilot study of gabapentin for co-occurring bipolar and cannabis use disorders

Disrupted brain gamma-aminobutyric acid (GABA)/glutamate homeostasis is a promising target for pharmacological intervention in co-occurring bipolar disorder (BD) and cannabis use disorder (CUD). Gabapentin is a safe and well-tolerated medication, FDA-approved to treat other neurological diseases, that restores GABA/glutamate homeostasis, with treatment studies supporting efficacy in treating CUD, as well as anxiety and sleep disorders that are common to both BD and CUD. The present manuscript represents the primary report of a randomized, double-blind, placebo-controlled, crossover (1-week/condition), multimodal-MRI (proton-MR spectroscopy, functional MRI) pilot study of gabapentin (1200 mg/day) in BD + CUD (n = 22). Primary analyses revealed that (1) gabapentin was well tolerated and adherence and retention were high, (2) gabapentin increased dorsal anterior cingulate cortex (dACC) and right basal ganglia (rBG) glutamate levels and (3) gabapentin increased activation to visual cannabis cues in the posterior midcingulate cortex (pMCC, a region involved in response inhibition to rewarding stimuli). Exploratory evaluation of clinical outcomes further found that in participants taking gabapentin versus placebo, (1) elevations of dACC GABA levels were associated with lower manic/mixed and depressive symptoms and (2) elevations of rBG glutamate levels and pMCC activation to cannabis cues were associated with lower cannabis use. Though promising, the findings from this study should be interpreted with caution due to observed randomization order effects on dACC glutamate levels and identification of statistical moderators that differed by randomization order (i.e. cigarette-smoking status on rBG glutamate levels and pMCC cue activation). Nonetheless, they provide the necessary foundation for a more robustly designed (urn-randomized, parallel-group) future study of adjuvant gabapentin for BD + CUD.

Clinical evaluation of the effects of a single oral dose of gabapentin on fear-based aggressive behaviors in cats during veterinary examinations

OBJECTIVE

To investigate the effects of a single oral dose of gabapentin on fear-based aggressive behaviors (FABs) in cats during veterinary examinations.

ANIMALS

55 healthy pet cats (26 with and 29 without a history of FAB during veterinary visits [FAB and untreated control groups, respectively]).

PROCEDURES

A standardized 9-step clinical examination protocol (with patient compliance scored from 0 to 9 according to the highest completed step) was tested on untreated control group cats. The protocol was then used in a double-blind, randomized, placebo-controlled, crossover-design trial in which FAB-group cats received owner-administered gabapentin (100 or 200 mg/cat) or placebo capsules 2 hours before the first of 2 veterinary visits and received the alternate treatment before the second visit ≥ 1 day later. Ease of administration (scored from 1 [very difficult] to 4 [very easy]) and adverse effects were recorded. Compliance scores were compared between treatments for the FAB group and between FAB and untreated control groups. Changes in scores between treatments for the FAB group were used to investigate associations between selected variables and the outcome of interest.

RESULTS

FAB group compliance scores after gabapentin administration (median, 9; range, 0 to 9) were significantly higher than scores after placebo administration (median 0.5; range, 0 to 7) and did not differ from scores for the untreated control group. Owner scores indicated capsule administration was easy. Adverse effects (most commonly drowsiness, myorelaxation, and ataxia) resolved ≤ 10 hours after detection.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested oral administration of gabapentin to cats 2 hours before a veterinary visit can reduce FAB during physical examination, enabling more complete evaluation.

Bipolar Disorder and Comorbid Use of Illicit Substances

Substance use disorders (SUD) are highly prevalent in bipolar disorder (BD) and significantly affect clinical outcomes. Incidence and management of illicit drug use differ from alcohol use disorders, nicotine use of behavioral addictions. It is not yet clear why people with bipolar disorder are at higher risk of addictive disorders, but recent data suggest common neurobiological and genetic underpinnings and epigenetic alterations. In the absence of specific diagnostic instruments, the clinical interview is conducive for the diagnosis. Treating SUD in bipolar disorder requires a comprehensive and multidisciplinary approach. Most treatment trials focus on single drugs, such as cannabis alone or in combination with alcohol, cocaine, or amphetamines. Synopsis of data provides limited evidence that lithium and valproate are effective for the treatment of mood symptoms in cannabis users and may reduce substance use. Furthermore, the neuroprotective agent citicoline may reduce cocaine consumption in BD subjects. However, many of the available studies had an open-label design and were of modest to small sample size. The very few available psychotherapeutic trials indicate no significant differences in outcomes between BD with or without SUD. Although SUD is one of the most important comorbidities in BD with a significant influence on clinical outcome, there is still a lack both of basic research and clinical trials, allowing for evidence-based and specific best practices.

Outpatient Off-Label Gabapentin Use for Psychiatric Indications Among U.S. Adults, 2011-2016

OBJECTIVE

Gabapentin is widely prescribed off label in medical practice, including psychiatry. The U.S. Food and Drug Administration (FDA) warned of risks associated with gabapentin combined with central nervous system depressant (CNS-D) drugs, which are commonly prescribed in psychiatric treatment. This study examined off-label outpatient gabapentin use for psychiatric indications and concomitant CNS-D medication use.

METHODS

National Ambulatory Care Medical Survey data (2011-2016) were used to identify encounters involving gabapentin (gabapentin visits) for adults (ages ≥18) (N=5,732). FDA-approved uses and off-label psychiatric use indications were identified with ICD-9-CM and ICD-10-CM diagnosis codes. CNS-D drugs examined were opioids, benzodiazepines, sedatives-hypnotics, antidepressants, antipsychotics, first-generation antihistamines, and skeletal muscle relaxants. Concomitance was prescription of one or more CNS-D medications at the same visit. Visits were stratified by provider type and specialty.

RESULTS

Between 2011 and 2016, 2.8% of visits listed gabapentin prescriptions (weighted estimate of 129.6 million visits). A small proportion (<1%) listed an FDA-approved indication. Among off-label gabapentin visits, 5.3% listed a depressive disorder, 3.5% an anxiety disorder, and 1.8% bipolar disorder. Over 6 years, 58.4% of off-label gabapentin visits listed one or more concomitant CNS-D medications, most frequently antidepressants (24.3%), opioids (22.9%), and benzodiazepines (17.3%). Most gabapentin visits were with primary care providers (34.9%) and other provider specialties (i.e., not primary care, neurology, or psychiatry) (48.1%).

CONCLUSION

In this nationally representative sample, <1% of outpatient gabapentin use was for approved indications. High concomitant use of CNS-D drugs and off-label gabapentin for psychiatric diagnoses underlines the need for improved communication about safety.

Effects of Gabapentin on Dorsal Anterior Cingulate Cortex GABA and Glutamate Levels and Their Associations With Abstinence in Alcohol Use Disorder: A Randomized Clinical Trial

OBJECTIVE

Although gabapentin has demonstrated efficacy in mitigating alcohol withdrawal symptoms and preventing relapse drinking in individuals with alcohol use disorder (AUD), the neurobiological mechanisms of action underlying these therapeutic effects remain unknown. The present study evaluated changes in GABA and glutamate levels in the dorsal anterior cingulate cortex (dACC) as candidate mechanisms of action.

METHODS

In a 16-week randomized clinical trial, 68 adults with AUD, including a history of alcohol withdrawal syndrome, received 1,200 mg/day of gabapentin (N=37) or placebo (N=31) and nine medical management visits after ≥72 hours of abstinence. Proton MR spectroscopy (¹H-MRS) estimates of dACC levels of GABA (N=67) and glutamate (N=64) were acquired before start of treatment and again approximately 14 days after randomization. Percent days abstinent was reported via timeline followback interview.

RESULTS

The effects of gabapentin on GABA and glutamate levels were significantly associated with participants' percent days abstinent during early treatment. Specifically, gabapentin was associated with greater increases in glutamate and greater decreases in GABA levels in participants who remained mostly or entirely abstinent, and yet the opposite in participants who drank on more than half of the days preceding the second scan. Furthermore, gabapentin-treated participants with greater increases in glutamate levels during early treatment had significantly more percent days abstinent across the remainder of the study, relative to placebo-treated participants.

CONCLUSIONS

In addition to providing insight into the mechanisms through which gabapentin may promote abstinence in individuals with AUD, this study also provides evidence for a biomarker of efficacious treatment that may be used to evaluate other glutamatergic or GABAergic medications for AUD and related conditions.

In silico Screening and Behavioral Validation of a Novel Peptide, LCGA-17, With Anxiolytic-Like Properties

The aim of the study was to develop better anxiolytics and antidepressants. We focused on GABA_A receptors and the α2δ auxiliary subunit of V-gated Ca²⁺ channels as putative targets because they are established as mediators of efficacious anxiolytics, antidepressants, and anticonvulsants. We further focused on short peptides as candidate ligands because of their high safety and tolerability profiles. We employed a structural bioinformatics approach to develop novel tetrapeptides with predicted affinity to GABA_A receptors and α2δ. In silico docking studies of one of these peptides, LCGA-17, showed a high binding score for both GABA_A receptors and α2δ, combined with anxiolytic-like properties in a Danio rerio behavioral screen. LCGA-17 showed anxiolytic-like effects in the novel tank test, the light–dark box, and the social preference test, with efficacy comparable to fluvoxamine and diazepam. In binding assays using rat brain membranes, [³H]-LCGA-17 was competed more effectively by gabapentinoid ligands of α2δ than ligands of GABA_A receptors, suggesting that α2δ represents a likely target for LCGA-17. [³H]-LCGA-17 binding to brain lysates was unaffected by competition with ligands for GABA_B, glutamate, dopamine, serotonin, and other receptors, suggesting specific interaction with α2δ. Dose-finding studies in mice using acute administration of LCGA-17 (i.p.) demonstrated anxiolytic-like effects in the open field test, elevated plus maze, and marble burying tests, as well as antidepressant-like properties in the forced swim test. The anxiolytic effects were effectively blocked by bicuculline. Therefore, LCGA-17 is a novel candidate anxiolytic and antidepressant that may act through α2δ, with possible synergism by GABA_A receptors.

Electroacupuncture prevents cocaine-induced conditioned place preference reinstatement and attenuates ΔFosB and GluR2 expression

Acupuncture has been used for treating drug addiction since the 1970s, but little is known about the mechanisms by which acupuncture affects drug cue-induced relapse. The transcription factor delta-FosB (ΔFosB) plays a critical role in behavior and pathology after chronic use of cocaine. ΔFosB regulates glutamate receptor signaling and dendritic spine morphology in animal models. This experimental study compared the effects of electroacupuncture (EA) at acupoints LI4 and LI11 with those of another potentially beneficial intervention, gabapentin (GBP), alone or in combination, on reinstatement of cocaine-induced conditioned place preference (CPP) and levels of ΔFosB and glutamate receptor subunit 2 (GluR2) expression in the nucleus accumbens (NAc). EA at LI4 and LI11 significantly prevented cue-induced cocaine CPP reinstatement, whereas needle insertion without electrical stimulation at these acupoints had no such effect. EA also significantly attenuated cocaine-induced increases in ΔFosB and GluR2 expression in the NAc. Unexpectedly, these effects were reversed when GBP was combined with EA. Treatment with EA at LI4 and LI11 prevented cocaine-induced increases in dendritic spine density in the NAc core and shell. Our results suggest that EA at LI4 and LI11 may prevent cocaine relapse by modulating ΔFosB and GluR2 expression, as well as dendritic spine density.

Drug-drug Interactions between COVID-19 Treatments and Antidepressants, Mood Stabilizers/Anticonvulsants, and Benzodiazepines: Integrated Evidence from 3 Databases

INTRODUCTION

The SARS-CoV-2 pandemic with psychiatric comorbidities leads to a scenario in which the use of psychotropic drugs may be required. This requires the support of evidence-based medicine to take into account possible interactions between antidepressants, mood stabilizers, benzodiazepines, and coronavirus infection treatments.

METHODS

Three databases were consulted: (a) Lexicomp Drug Interactions, (b) Micromedex Solutions Drugs Interactions, (c)Liverpool Drug Interaction Group for COVID-19 therapies. The CredibleMeds QTDrugs List was also queried. Hydroxychloroquine, chloroquine, azithromycin, lopinavir-ritonavir, remdesivir, favipiravir, tocilizumab, baricitinib, anakinra, and dexamethasone - drugs used for SARS-CoV-2 - were analyzed, and consensus recommendations are made.

RESULTS

The potential interactions of agomelatine, desvenlafaxine, duloxetine, milnacipran, and vortioxetine with COVID-19 treatments shall be considered less risky. Antidepressant interactions with hydroxychloroquine, chloroquine, and azithromycin enhance the risk of QT prolongation, and ECG monitoring is advised for most antidepressants. Antidepressants with lopinavir/ritonavir involve multiple CYP enzyme interactions (except with milnacipran). Gabapentin, oxcarbazepine, pregabalin, topiramate, and zonisamide are safe treatment options that have no significant interactions with COVID-19 treatments. Lithium is contraindicated with hydroxychloroquine, chloroquine, and azithromycin. Precaution should be taken in using valproic acid with lopinavir-ritonavir. The use of benzodiazepines does not present a risk of drug interaction with COVID-19 treatments, except lopinavir/ritonavir.

CONCLUSIONS

Clinicians prescribing antidepressants, mood stabilizers/anticonvulsants, and benzodiazepines, should be aware of the probable risk of drug-drug interaction with COVID-19 medications and may benefit from heeding these recommendations for use to ensure patient safety.

Pharmacotherapy of Anxiety Disorders: Current and Emerging Treatment Options

(Appeared originally in Frontiers in Psychiatry 2020 Dec 23; 11:595584)

Effects of a single oral dose of gabapentin on storm phobia in dogs: A double-blind, placebo-controlled crossover trial

BACKGROUND

Storm phobia in companion dogs is a common disorder that significantly impacts dogs' welfare. Gabapentin, the action of which is only partially understood, is widely used for its antiepileptic and analgesic properties. Only recently, the veterinary community began to use gabapentin to address phobia and anxiety in dogs. This study tested gabapentin to lower fear responses of dogs during a thunderstorm event.

METHODS

Eighteen dogs suffering from storm phobia completed our double-blind, placebo-controlled crossover trial. Each dog's behaviour was evaluated twice by his owner: once under placebo, once under gabapentin. The treatment was orally administered at least 90 min before the exposure. Gabapentin was given at a dose ranging from 25 to 30 mg/kg.

RESULTS

Our results indicate a significant reduction of the fear responses of dogs under gabapentin. The adverse effects were rare, and the most frequent amongst them was ataxia.

CONCLUSION

In this trial, gabapentin appears to be an efficient and safe molecule that should be considered as part of the treatment plan of storm phobia in dogs.

Gabapentin attenuates somatic signs of precipitated THC withdrawal in mice

Cannabis is the most frequently used federally illicit substance in the United States. However, there are currently no FDA-approved pharmacotherapies to mitigate the withdrawal symptoms associated with cessation in heavy users. A promising, readily available, non-cannabinoid therapy are the gabapentinoids. Although currently approved for epilepsy and neuropathic pain, gabapentinoids are increasingly used for their "off-label" efficacy in treating various psychiatric conditions and substance abuse. Gabapentin (GBP) synergizes with cannabinoid agonism in neuropathic pain models, substitutes for Δ⁹-tetrahydrocannabinol (THC) in drug discrimination procedures, and reduced withdrawal symptoms in an outpatient clinical trial. However, there are limited data on the biological plausibility of the therapeutic action of gabapentinoids in cannabinoid withdrawal in preclinical models. The purpose of the current study was to determine the efficacy of GBP on attenuating THC withdrawal in mice, using an array of tests targeting withdrawal-induced and withdrawal-suppressed behaviors. Separate cohorts of male and female mice were administered THC (10 mg/kg, s.c.) or vehicle for 5.5 days, and withdrawal was precipitated by the CB₁ antagonist rimonabant (2 or 3 mg/kg, i.p.) on the sixth day. GBP (≥10 mg/kg) reduced somatic signs of withdrawal (i.e., paw tremors and head twitches), but had no effect in locomotor activity or conditioned place preference. GBP (50 mg/kg) also restored withdrawal-suppressed responding on a progressive ratio reinforcement schedule. However, GBP (50 mg/kg) had no effect in withdrawal-suppressed marble burying or tail suspension struggling and did not normalize the stress response induced by THC withdrawal, as indicated by plasma corticosterone. These data suggest gabapentin may be effective at treating cannabinoid withdrawal symptoms including somatic and affective symptoms but may act independently of endocrine stress activation.

Risk factors for natural cause mortality in a cohort of 1494 persons with serious mental illness

Persons with serious mental illness die on average more than 10 years younger than those in the overall population, mostly due to natural causes. Previous studies have identified predictors of natural cause mortality in this population but few have been prospective studies using clinical variables from in-person evaluations. A cohort of 1494 individuals with schizophrenia, bipolar disorder, or major depressive disorder were assessed at baseline and mortality status was determined from the US National Death Index after up to 20 years of follow-up. Analyses included multivariate Cox proportional hazard models to determine independent predictors of natural cause mortality. A total of 125 (8.4%) individuals died of natural causes. In multivariate models, the strongest predictor of mortality after age was tobacco smoking at baseline with a dose-related effect. Having diabetes, a cardiovascular condition, particularly hypertension, and lower cognitive functioning were also significant risks, along with divorced/separated status. The receipt of gabapentin or fluoxetine also significantly increased mortality risk. Premature death can be reduced by smoking cessation and the improved management of conditions such as hypertension and diabetes.

Assessment of gabapentin misuse using prescription drug monitoring program data

BACKGROUND

Gabapentin is an anticonvulsant medication with potential misuse reported in case reports and population studies, highlighting the need to reexamine its abuse liability. The purpose of this study was to describe gabapentin dispensing patterns and assess potential misuse. Methods: We used data from Ohio's Prescription Drug Monitoring Program (PDMP) from December 1, 2016 to March 31, 2017 and restricted the population to adults who filled at least one gabapentin prescription (N = 379,372). Gabapentin dispensing patterns are described and multiple strategies were used to assess potential misuse, including Lorenz-1 curve analysis. Supratherapeutic dosing, number of prescribers and number of pharmacies used were compared for individuals who were co-dispensed medications for opioid use disorder (MOUD) and those who were not. Results: More than one million gabapentin prescriptions were dispensed during the 4-month period, with a mean dose of 1103.8 mg. While few individuals received supratherapeutic dosing, exceptionally high doses were observed. Half of the individuals (50.9%) were co-dispensed gabapentin and opioids. The Lorenz-1 value for gabapentin (5.5%) did not exceed the threshold for misuse potential. Individuals co-dispensed MOUD were more likely to have supratherapeutic dosing; however, they had a lower Lorenz-1 value compared to individuals not co-dispensed MOUD. Conclusions: Among Ohio residents dispensed gabapentin, there was no evidence of misuse using PDMP data based on the Lorenz-1 value, yet supratherapeutic dosing of gabapentin was observed and was associated with OUD. New strategies may be needed to identify the non-medical use of gabapentin.

Gabapentinoid Benefit and Risk Stratification: Mechanisms Over Myth

INTRODUCTION

Recent years have seen a dramatic escalation of off-label prescribing for gabapentin and pregabalin (gabapentinoids) owing in part to generic versions of each being released over the past two decades, but also in part as a response to increasing calls for multimodal and non-opioid pain management strategies. In this context, several recent articles have been published alleging widespread misuse, with speculations on the unappreciated addictive potential of the gabapentinoid class of drugs. Reports of a 1% population-level abuse prevalence stem from a single internet survey in the UK, and the vanishingly small adverse event outcomes data do not support such frequency. In this targeted narrative review, we aim to disabuse pain physicians and other clinicians, pharmacists, and policymakers of both the positive and negative myths concerning gabapentinoid medications.

RESULTS

Gabapentinoids inhibit the joint action of voltage-gated calcium channel (VGCC) α2δ subunits in conjunction with the n-methyl-D-aspartate (NMDA) receptor, with subsequent downregulation of VGCC expression and excitatory neurotransmitter release, and possibly synaptogenesis as well, through actions on thrombospondins. These activities reduce the likelihood of central sensitization, which explains in part the efficacy of the gabapentinoids in the management of neuropathic pain. Gabapentinoids also facilitate slow-wave sleep, a relatively rare phenomenon among central nerve system-acting agents, which is also thought to explain some of the therapeutic benefit of the class in conditions such as fibromyalgia. The number needed to treat to see benefit overlaps that of the nonsteroidal anti-inflammatory drugs, but with a considerably improved safety profile. Along these lines, in the context of over 50 million prescriptions per year in the USA alone, the gabapentinoids display remarkably low risk, including risks of misuse, abuse, and dependence. Furthermore, the neurobiology of these agents does not lend plausibility to the allegations, as they have never been shown to elicit dopaminergic activity within the nucleus accumbens, and in addition likely confer a "negative-feedback loop" for habituation and dependence by serving as functional NMDA antagonists, possibly through their actions on thrombospondins. Clinical and epidemiological addictionology studies corroborate the lack of any significant addictive potential of the gabapentinoids, and these drugs are increasingly being used in the treatment of addiction to other substances, with excellent results and no evidence of cross-addiction. However, among individuals with other substance use disorders and, in particular opioid use disorder, there are consistent data showing misuse of gabapentinoids in up to 20% of this population. Although there are allegations of using gabapentinoids to amplify the hedonic effects of opioids, the vast majority of misuse events appear to occur in an attempt to ameliorate opioid withdrawal symptoms. Furthermore, rare but potentially serious respiratory depression may occur, again amplified in the context of opioid or other sedative use. Careful risk:benefit assessment and stratification are warranted when prescription of a gabapentinoid is under consideration, in particular among individuals using opioids.

CONCLUSIONS

Gabapentinoids remain a vital tool in the pain physician's multimodal armamentarium, but these drugs may not be effective in every clinical situation. Individuals with central sensitization and pain associated with slow-wave sleep deficits and potentially persons with comorbid addictions may benefit the most. The gabapentinoids appear to possess no addictive potential on their own, based on laboratory and clinical data, but they may be abused by persons with opioid use disorders; consequently, cautious risk stratification must take place.

Gabapentin for Post-Hospitalization Alcohol Relapse Prevention; Should Gabapentin Be Considered for FDA Approval in the Treatment of Alcohol Use Disorder?: A Case Presentation and Literature Review

Alcohol use disorder (AUD), a chronic condition that affects many people worldwide, is characterized most commonly by a preoccupation with alcohol, an irresistible craving for or the inability to control the consumption of alcohol, and the marked resultant disturbance it bestows upon one’s life. Although a difficult and time-consuming condition to attempt to treat, there are currently three FDA-approved medications for AUD, including naltrexone, acamprosate, and disulfiram. However, literature points towards another agent, gabapentin, that may be efficacious in preventing relapse symptoms and cravings with enhanced effectivity in reducing post-hospitalization alcohol consumption behaviors. In this paper, we discuss a case presentation and literature review demonstrating the role of gabapentin in treating AUD and symptoms associated with alcohol withdrawal, along with its potential use in relapse prevention.

Efficacy of Gabapentin for the Treatment of Alcohol Use Disorder in Patients With Alcohol Withdrawal Symptoms: A Randomized Clinical Trial

IMPORTANCE

Although an estimated 30 million people meet criteria for alcohol use disorder (AUD), few receive appropriate pharmacotherapy. A more personalized, symptom-specific, approach might improve efficacy and acceptance.

OBJECTIVE

To examine whether gabapentin would be useful in the treatment of AUD, especially in those with the most alcohol withdrawal symptoms.

DESIGN, SETTING, AND PARTICIPANTS

This double-blind randomized clinical trial conducted between November 2014 and June 2018 evaluated gabapentin vs placebo in community-recruited participants screened and treated in an academic outpatient setting over a 16-week treatment period. A total of 145 treatment-seeking individuals who met Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) criteria for AUD and were not receiving other AUD intervention were screened, and 96 who also met recent alcohol withdrawal criteria were randomized to treatment after 3 abstinent days. Daily drinking was recorded, and percentage of disialo carbohydrate-deficient transferrin in the blood, a heavy drinking marker, was collected at baseline and monthly during treatment.

INTERVENTIONS

Gabapentin up to 1200 mg/d, orally, vs placebo along with 9 medical management visits (20 minutes each).

MAIN OUTCOMES AND MEASURES

The percentage of individuals with no heavy drinking days and those with total abstinence were compared between treatment groups and further evaluated based on prestudy alcohol withdrawal symptoms.

RESULTS

Of 96 randomized individuals, 90 were evaluable (44 in the gabapentin arm and 46 in the placebo arm), with a mean (SD) age of 49.6 (10.1) years; 69 were men (77%) and 85 were white (94%). The evaluable participants had 83% baseline heavy drinking days (4 or more drinks/day for women, 5 or more for men) and met 4.5 alcohol withdrawal criteria from the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition). More gabapentin-treated individuals had no heavy drinking days (12 of 44 participants [27%]) compared with placebo (4 of 46 participants [9%]), a difference of 18.6% (95% CI, 3.1-34.1; P = .02; number needed to treat [NNT], 5.4), and more total abstinence (8 of 44 [18%]) compared with placebo (2 of 46 [4%]), a difference of 13.8% (95% CI, 1.0-26.7; P = .04; NNT, 6.2). The prestudy high-alcohol withdrawal group had positive gabapentin effects on no heavy drinking days (P < .02; NNT, 3.1) and total abstinence (P = .003; NNT, 2.7) compared with placebo, while within the low-alcohol withdrawal group, there were no significant differences. These findings were similar for other drinking variables, where gabapentin was more efficacious than placebo in the high-alcohol withdrawal group only. Gabapentin caused more dizziness, but this did not affect efficacy.

CONCLUSIONS AND RELEVANCE

These data, combined with others, suggest gabapentin might be most efficacious in people with AUD and a history of alcohol withdrawal symptoms. Future studies should evaluate sleep changes and mood during early recovery as mediators of gabapentin efficacy.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02349477.

Pharmacotherapy of Anxiety Disorders: Current and Emerging Treatment Options

Anxiety disorders are the most prevalent psychiatric disorders and a leading cause of disability. While there continues to be expansive research in posttraumatic stress disorder (PTSD), depression and schizophrenia, there is a relative dearth of novel medications under investigation for anxiety disorders. This review's first aim is to summarize current pharmacological treatments (both approved and off-label) for panic disorder (PD), generalized anxiety disorder (GAD), social anxiety disorder (SAD), and specific phobias (SP), including selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), azapirones (e.g., buspirone), mixed antidepressants (e.g., mirtazapine), antipsychotics, antihistamines (e.g., hydroxyzine), alpha- and beta-adrenergic medications (e.g., propranolol, clonidine), and GABAergic medications (benzodiazepines, pregabalin, and gabapentin). Posttraumatic stress disorder and obsessive-compulsive disorder are excluded from this review. Second, we will review novel pharmacotherapeutic agents under investigation for the treatment of anxiety disorders in adults. The pathways and neurotransmitters reviewed include serotonergic agents, glutamate modulators, GABAergic medications, neuropeptides, neurosteroids, alpha- and beta-adrenergic agents, cannabinoids, and natural remedies. The outcome of the review reveals a lack of randomized double-blind placebo- controlled trials for anxiety disorders and few studies comparing novel treatments to existing anxiolytic agents. Although there are some recent randomized controlled trials for novel agents including neuropeptides, glutamatergic agents (such as ketamine and d-cycloserine), and cannabinoids (including cannabidiol) primarily in GAD or SAD, these trials have largely been negative, with only some promise for kava and PH94B (an inhaled neurosteroid). Overall, the progression of current and future psychopharmacology research in anxiety disorders suggests that there needs to be further expansion in research of these novel pathways and larger-scale studies of promising agents with positive results from smaller trials.

Review: Does Gabapentin Relieve Opioids, Cannabis and Methamphetamines Addictions?

The study reviews the suitability of using Gabapentin for treating opioid, cannabis and methamphetamine use disorders. This revision consists of 61 biographical references based on a PubMed database search (January of 1983-May of 2018). Gabapentin displayed respectively 50% and 66.7% of success for treating methamphetamine dependence and opioid withdrawal symptoms. Furthermore, a few research studies have reported Gabapentin´s efficacy for alleviating cannabis dependence (two studies), and cannabis withdrawal symptoms (one study). Similarly, a single study reported Gabapentin reduction of opioid consumption during the detoxification process. Based on the revision, we can conclude that: (a) Gabapentin is useful for treating opioid withdrawal symptoms, (b) additional studies are necessary for elucidating the effectiveness of Gabapentin for treating methamphetamine dependence, cannabis dependence and its withdrawal symptoms, and (c) more studies are necessary to confirm the efficacy of Gabapentin in reducing opioid consumption during detoxification.

Epileptic Spikes in EEG and Migraine Attacks in the Course of Cannabis Withdrawal: A Case Report

In psychiatry, routine EEGs are often abnormal and not very specific, raising questions about the clinical relevance and consequences of potential anomalies. One such question is whether the administration of anticonvulsants would be useful if epileptic discharges are detected in patients without any clinical correlates. With regard to this question, we present a case study in which abnormal EEG patterns were observed in a patient with chronic migraine and cannabis addiction. The patient was a 34-year-old woman with a 14-year history of cannabis abuse who, during withdrawal, showed epileptic spikes, without any corresponding clinical symptoms, and migraine attacks of increasing intensity and frequency. This case study is in line with the new DSM-5 diagnostic tool that for the first time includes the diagnosis of cannabis withdrawal.