Trends in gabapentin and baclofen exposures reported to U.S. poison centers

Non-medical use of baclofen: A case series and review of the literature

BACKGROUND

Baclofen is widely used for spastic disorders and, most recently, for addictive disorders. The first signals of baclofen abuse occurred in the last decade. This study aims to assess the motives, diversion sources, and routes of administration associated with the non-medical use of baclofen and examine health problems related to the non-medical use of baclofen.

METHODS

Spontaneous reports of baclofen abuse reported to the addictovigilance centre of East France were analysed. A literature search was conducted using PubMed®, Web of Sciences®, and Google Scholar® databases. Both investigations were performed in February 2021 without a time limit.

RESULTS

Forty-six cases were analysed (33 from the literature review and 13 from the addictovigilance base). Baclofen's non-medical use mainly affected male subjects with addictive history, but issues of primary abuse in subjects without any substance abuse history were also observed. Euphoria search was the most common reason for misuse. The route of administration included oral, snorting, and sublingual use. Some cases involving illegal sources were also observed. Most patients misusing baclofen presented severe complications, mainly represented by neurological and respiratory disturbances. Physical and psychological dependence on baclofen was observed in three persons.

CONCLUSIONS

Although baclofen abuse remains relatively infrequent or (most likely) underestimated, this study helped confirm baclofen's intrinsic abuse potential and make visible the baclofen-abuse-related health visible harms. Careful consideration and benefit-risk analysis should be employed when prescribing baclofen, and emergency departments should be aware of baclofen dangers in abuse situations.

Drug Safety and Suicidality Risk of Chronic Pain Medications

Chronic pain is one of the main leading causes of disability in the world at present. A variety in the symptomatology, intensity and duration of this phenomenon has led to an ever-increasing demand of pharmacological treatment and relief. This demand for medication, ranging from well-known groups, such as antidepressants and benzodiazepines, to more novel drugs, was followed by a rise in safety concerns of such treatment options. The validity, frequency, and diversity of such concerns are discussed in this paper, as well as their possible effect on future prescription practices. A specific caution is provided towards the psychological safety and toll of these medications, regarding suicidality and suicidal ideation. Most significantly, this paper highlights the importance of pharmacovigilance and underscores the necessity of surveillance programs when considering chronic pain medication.

Long-term Psychoactive Medications, Polypharmacy, and Risk of Suicide and Unintended Overdose Death Among Midlife and Older Women Veterans

BACKGROUND

Rates of suicide and unintended overdose death are high among midlife and older women, yet there is paucity of data identifying women at greatest risk. Psychoactive medications, commonly prescribed and co-prescribed in this population, may serve as salient indicators of risk for these outcomes.

OBJECTIVE

To determine whether long-term psychoactive medications and psychoactive polypharmacy predict risk of suicide and unintended overdose death among midlife and older women Veterans above and beyond other recognized factors.

DESIGN

Longitudinal cohort study PARTICIPANTS: Women Veterans aged ≥ 50 with at least one Veterans Health Administration (VHA) clinical encounter in FY2012-2013.

MAIN MEASURES

Long-term psychoactive medications (opioids, benzodiazepines, sedative-hypnotics, antidepressants, antipsychotics, and antiepileptics, prescribed for ≥ 90/180 days) and psychoactive polypharmacy (overlapping for ≥ 1 day) from VHA pharmacy records; suicide and unintended overdose death through December 31, 2018.

KEY RESULTS

In this national sample of 154,558 midlife and older women Veterans (mean age 63.4, SD 9.3 years), 130 died by suicide and 175 died from unintentional overdose over an average of 5.6 years. In fully adjusted models, long-term opioids (hazard ratio (HR) 2.01, 95% CI 1.21-3.35) and benzodiazepines (HR 2.99, 95% CI 1.82-4.91) were associated with death by suicide; opioids (HR 3.62, 95% CI 2.46-5.34), benzodiazepines (HR 2.77, 95% CI 1.73-4.42), sedative-hypnotics (HR 1.87, 95% CI 1.06-3.29), antidepressants (HR 1.47, 95% CI 1.03-2.12), antipsychotics (HR 1.81, 95% CI 1.02-3.22), and antiepileptics (HR 2.17, 95% CI 1.48-3.19) were associated with unintended overdose death. Women who were co-prescribed ≥ 3 psychoactive medications had over 2-fold increased risk of suicide (HR 2.83, 95% CI 1.65-4.84) and unintended overdose death (HR 2.60, 95% CI 1.72-3.94).

CONCLUSIONS

Long-term psychoactive medications and psychoactive medication polypharmacy were important indicators of risk for death by suicide and death by unintended overdose among midlife and older women Veterans, even after accounting for psychiatric and substance use disorders.

Manual plasma exchange to treat an accidental overdose of intravenous lipid emulsion in a dog with baclofen toxicosis

CASE DESCRIPTION

An approximately 2-year-old sexually intact male German Shorthair Pointer was presented for treatment of baclofen toxicosis.

CLINICAL FINDINGS

The dog had signs of severe baclofen toxicosis (no gag reflex, intermittent vocalization, and stupor) and received intravenous lipid emulsion (142 mL/kg) as a constant rate infusion over 11 hours. Severe hypertriglyceridemia (29,221 mg/dL; reference interval, 19 to 133 mg/dL) developed, followed by cardiovascular depression (poor peripheral perfusion, hyperlactatemia, and hypertension), severe hypoglycemia (26 mg/dL), acute kidney injury (serum creatinine, 3.6 mg/dL), intravascular hemolysis, and coagulopathy (hypocoagulable thromboelastogram and marked bilateral epistaxis).

TREATMENT AND OUTCOME

Therapeutic plasma exchange was performed in 4 stages to treat the hypertriglyceridemia. For each stage, an approximately 500-mL aliquot of blood (22 mL/kg) was removed and centrifuged, and the patient’s RBCs and allogenic fresh-frozen plasma were returned to the dog. Approximately 1.2 times the dog’s plasma volume was exchanged, reducing the serum triglyceride concentration to 1,349 mg/dL and improving the dog’s cardiovascular function and coagulation. Hours after the procedure was completed, the dog regurgitated and developed acute respiratory distress as a result of presumptive aspiration pneumonia, and the owner elected to have the dog euthanized.

CLINICAL RELEVANCE

Veterinarians should be aware of possible complications associated with administration of intravenous lipid emulsion, and veterinary-specific guidelines for the maximum dose of intravenous lipid emulsion should be developed to help prevent adverse effects. TPE appears to be an effective method for treating iatrogenic hypertriglyceridemia in dogs.

Central nervous system polytherapy among veterans with posttraumatic stress disorder: changes across a decade

OBJECTIVE

The study objectives were to investigate rates and patterns of polytherapy among veterans with PTSD across time (in 2009 and 2019), describe features of polytherapy prescribing, and identify demographic and clinical factors associated with polytherapy.

METHODS

Veterans Affairs (VA) administrative data were used to build cohorts of all VA-served veterans with PTSD in 2009 (N = 458,620) and 2019 (N = 877,785). Frequency of CNS active drug classes, rates of polytherapy (≥5 concurrent CNS drugs), clinical features associated with polytherapy, number of prescribers, and patterns of co-prescribed medications were examined.

RESULTS

The 12-month period prevalence of CNS polytherapy declined from 12.1% in 2009 to 6.9% in 2019. However, polytherapy rates increased from 3.3% in 2009 to 4.1% in 2019, when opioids and benzodiazepines were excluded. In multivariable regression analysis, CNS polytherapy was more common among women, White people, middle-age veterans (45-64 years), rural residents, veterans receiving care at a medical center, and those with psychiatric comorbidities. CNS polytherapy regimens involved a mean of 2.3 prescribers and the majority (86.6%) included at least one medication commonly prescribed for pain management.

CONCLUSIONS

CNS polytherapy declined among veterans with PTSD from 2009 to 2019 and was wholly attributable to decreases in opioid and benzodiazepine prescribing.

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.

Extracorporeal Treatment for Gabapentin and Pregabalin Poisoning: Systematic Review and Recommendations From the EXTRIP Workgroup

Toxicity from gabapentin and pregabalin overdose is commonly encountered. Treatment is supportive, and the use of extracorporeal treatments (ECTRs) is controversial. The EXTRIP workgroup conducted systematic reviews of the literature and summarized findings following published methods. Thirty-three articles (30 patient reports and 3 pharmacokinetic studies) met the inclusion criteria. High gabapentinoid extracorporeal clearance (>150mL/min) and short elimination half-life (<5 hours) were reported with hemodialysis. The workgroup assessed gabapentin and pregabalin as "dialyzable" for patients with decreased kidney function (quality of the evidence grade as A and B, respectively). Limited clinical data were available (24 patients with gabapentin toxicity and 7 with pregabalin toxicity received ECTR). Severe toxicity, mortality, and sequelae were rare in cases receiving ECTR and in historical controls receiving standard care alone. No clear clinical benefit from ECTR could be identified although major knowledge gaps were acknowledged, as well as costs and harms of ECTR. The EXTRIP workgroup suggests against performing ECTR in addition to standard care rather than standard care alone (weak recommendation, very low quality of evidence) for gabapentinoid poisoning in patients with normal kidney function. If decreased kidney function and coma requiring mechanical ventilation are present, the workgroup suggests performing ECTR in addition to standard care (weak recommendation, very low quality of evidence).

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.

Coprescription of Opioids With Other Medications and Risk of Opioid Overdose

Polypharmacy is common among patients taking prescription opioids long-term, and the codispensing of interacting medications may further increase opioid overdose risk. To identify nonopioid medications that may increase opioid overdose risk in this population, we conducted a case-crossover-based screening of electronic claims data from IBM MarketScan and Optum Clinformatics Data Mart spanning 2003 through 2019. Eligible patients were 18 years of age or older and had at least 180 days of continuous enrollment and 90 days of prescription opioid use immediately before an opioid overdose resulting in an emergency room visit or hospitalization. The main analysis quantified the odds ratio (OR) between opioid overdose and each nonopioid medication dispensed in the 90 days immediately before the opioid overdose date after adjustment for prescription opioid dosage and benzodiazepine codispensing. Additional analyses restricted to patients without cancer diagnoses and individuals who used only oxycodone for 90 days immediately before the opioid overdose date. The false discovery rate (FDR) was used to account for multiple testing. We identified 24,866 individuals who experienced opioid overdose. Baclofen (OR 1.56; FDR < 0.01; 95% confidence interval (CI), 1.29 to 1.89), lorazepam (OR 1.53; FDR < 0.01; 95% CI, 1.25 to 1.88), and gabapentin (OR 1.16; FDR = 0.09; 95% CI, 1.04 to 1.28), among other nonopioid medications, were associated with opioid overdose. Similar patterns were observed in noncancer patients and individuals who used only oxycodone. Interventions may focus on prescribing safer alternatives when a potential for interaction exists.

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.

Classics in Chemical Neuroscience: Baclofen

Baclofen, β-(4-chlorophenyl)-γ-aminobutyric acid, holds a unique position in neuroscience, remaining the only U.S. Food and Drug Administration (FDA) approved GABA_B agonist. While intended to be a more brain penetrant, i.e, ability to cross the blood-brain barrier (BBB), version of GABA (γ-aminobutyric acid) for the potential treatment of epilepsy, baclofen's highly efficacious muscle relaxant properties led to its approval, as a racemate, for the treatment of spasticity. Interestingly, baclofen received FDA approval before its receptor, GABA_B, was discovered and its exact mechanism of action was known. In recent times, baclofen has a myriad of off-label uses, with the treatment for alcohol abuse and drug addiction garnering a great deal of attention. This Review aims to capture the >60 year legacy of baclofen by walking through the history, pharmacology, synthesis, drug metabolism, routes of administration, and societal impact of this Classic in chemical neuroscience.