Review about gabapentin misuse, interactions, contraindications and side effects

European randomized controlled trial evaluating differential target multiplexed spinal cord stimulation and conventional medical management in subjects with persistent back pain ineligible for spine surgery: 24-month results

BACKGROUND

Differential target multiplexed spinal cord stimulation (DTM SCS) was shown to be superior to conventional SCS for treating chronic low back pain (CLBP) in subjects with persistent spinal pain syndrome with previous spinal surgery (PSPS-T2) or ineligible for it (PSPS-T1). This study reports 24-month efficacy and safety of DTM SCS vs. conventional medical management (CMM) in PSPS-T1 subjects across four European countries.

METHODS

This is a prospective, multicenter, open-label, randomized, controlled trial with optional crossover. Subjects randomized 1:1 to DTM SCS or CMM. Primary endpoint was responder rate (% subjects reporting ≥50% CLBP relief) at 6 months. A superiority test compared responder rates between treatments. CLBP and leg pain levels, functional disability, quality of life (QoL), patient satisfaction and global impression of change were evaluated for 24 months. A Composite Responder Index (CRI) was obtained using CLBP relief, disability and QoL. Incidence of study-related adverse events evaluated safety.

RESULTS

A total of 55 and 57 subjects were randomized to DTM SCS and CMM respectively. DTM SCS was superior, with CLBP responder rates ≥80% and CLBP relief >5.6 cm (>70% reduction) through the 24-month follow-up. Improvements with DTM SCS in other outcomes were sustained. The CRI was >80% for DTM SCS through 24 months. Opioid medication intake decreased in subjects treated with DTM SCS. Most patients treated with DTM SCS felt satisfied and improved at the end of the study. Safety was congruent with other studies.

CONCLUSION

DTM SCS is efficacious and safe during 24 months for the treatment of CLBP and leg pain in PSPS-T1 patients ineligible for spine surgery.

SIGNIFICANCE STATEMENT

This randomized controlled trial shows that Differential Target Multiplexed SCS (DTM SCS) is an effective and safe long-term treatment for PSPS type 1 patients suffering from axial low back pain with or without leg pain and who are ineligible for spinal surgery. Currently, CMM treatments are their only option and provide limited benefits. Besides superior pain relief, DTM SCS provides significant improvements in functional disability, quality of life, high levels of satisfaction and perceived impression of change.

Venom-inspired somatostatin receptor 4 (SSTR4) agonists as new drug leads for peripheral pain conditions

Persistent pain affects one in five people worldwide, often with severely debilitating consequences. Current treatment options, which can be effective for mild or acute pain, are ill-suited for moderate-to-severe persistent pain, resulting in an urgent need for new therapeutics. In recent years, the somatostatin receptor 4 (SSTR 4 ), which is expressed in sensory neurons of the peripheral nervous system, has emerged as a promising target for pain relief. However, the presence of several closely related receptors with similar ligand-binding surfaces complicates the design of receptor-specific agonists. In this study, we report the discovery of a potent and selective SSTR 4 peptide, consomatin Fj1, derived from extensive venom gene datasets from marine cone snails. Consomatin Fj1 is a mimetic of the endogenous hormone somatostatin and contains a minimized binding motif that provides stability and drives peptide selectivity. Peripheral administration of synthetic consomatin Fj1 provided analgesia in mouse models of postoperative and neuropathic pain. Using structure-activity studies, we designed and functionally evaluated several Fj1 analogs, resulting in compounds with improved potency and selectivity. Our findings present a novel avenue for addressing persistent pain through the design of venom-inspired SSTR 4 -selective pain therapeutics.

One Sentence Summary

Venom peptides from predatory marine mollusks provide new leads for treating peripheral pain conditions through a non-opioid target.

The impact of novel inflammation-preserving treatment towards lumbar disc herniation resorption in symptomatic patients: a prospective, multi-imaging and clinical outcomes study

PURPOSE

We performed a prospective one-year multi-imaging study to assess the clinical outcomes and rate of disc resorption in acute lumbar disc herniation (LDH) patients undergoing inflammation-preserving treatment (i.e. no NSAIDS, steroids).

METHODS

All patients received gabapentin to relieve leg pain, 12 sessions of acupuncture. Repeat MRI was performed, every 3 months, after 12 sessions of treatment continued for those without 40% reduction in herniated disc sagittal area. Disc herniations sizes were measured on sagittal T2W MRI sequences, pre-treatment and at post-treatment intervals. Patients were stratified to fast, medium, slow, and prolonged recovery groups in relation to symptom resolution and disc resorption.

RESULTS

Ninety patients (51% females; mean age: 48.6 years) were assessed. Mean size of disc herniation was 119.54 ± 54.34 mm2, and the mean VAS-Leg score was 6.12 ± 1.13 at initial presentation. A total of 19 patients (21.1%) improved at the time of the repeat MRI (i.e. within first 3 months post-treatment). 100% of all patient had LDH resorption within one year (mean: 4.4. months). There was no significant difference at baseline LDH between fast, medium, slow, and prolonged resorption groups. Initial LDH size was weakly associated with degree of leg pain at baseline and initial gabapentin levels. Surgery was avoided in all cases.

CONCLUSION

This is the first study to note inflammation-preserving treatment, without conventional anti-inflammatory and steroid medications, as safe and effective for patients with an acute LDH. Rate of disc resorption (100%) was higher than comparative recent meta-analysis findings (66.7%) and no patient underwent surgery.

Nutraceutical supplementation increases mobility in aged captive non-domesticated felids

BACKGROUND

Musculoskeletal diseases (MSDs) are an increasing issue as the lifespan of captive animals increases. Extracts of green-lipped mussels have been linked to alleviation of MSDs in domestic carnivores. Understanding their efficacy in non-domestic felids could provide another tool to improve the welfare of aged individuals in collections.

METHODS

A within-subject study design quantified steps per minute in each of 18 cats of 13 species before and after the addition of a nutraceutical containing green-lipped mussel extract (Antinol) to their diets. The age structure of four commonly kept subspecies of non-domestic cats was quantified to provide a demographic context to the need for managing aged individuals.

RESULTS

Each of the 18 cats exhibited a higher number of steps per minute after the addition of Antinol to their diet. At the group level, a paired t-test showed that the step rate was significantly increased after the addition of Antinol to the diet.

LIMITATIONS

While our results showed a strong significant increase in step rate following Antinol supplementation, further studies that incorporate a placebo, more individuals and more detailed metrics of mobility would provide a more detailed evidence base for practitioners.

CONCLUSION

Nutraceuticals may yield benefits to aged individual felids, including species kept widely in European collections. Their use warrants further, detailed research in collections.

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.

Efficient and eco-friendly detection of gabapentin using nitrogen-doped carbon quantum dots: an analytical and green chemistry approach

This study presents the development of an eco-friendly and highly selective mitrogen-doped carbon quantum dot based sensor (N-CQDs) for the detection of gabapentin - a commonly misused drug. A detailed characterization of N-CQDs spectral features and their interaction with gabapentin is provided. The optimal conditions for sensing, including pH value, buffer volume, N-CQDs concentration, and incubation time, were established. The results showed excellent fluorescence quenching at 475 nm (λex = 380 nm) due to the dynamic quenching mechanism, and the sensor demonstrated excellent linearity in the 0.5-8.0 μg mL-1 concentration range with correlation coefficients of more than 0.999, a limit of detection (LOD) of 0.160 and limit of quantification (LOQ) of 0.480 μg mL-1. The accuracy of the proposed sensor was acceptable with a mean accuracy of 99.91 for gabapentin detection. In addition, precision values were within the acceptable range, with RSD% below 2% indicating good repeatability and reproducibility of the sensor. Selectivity was validated using common excipients and pooled plasma samples. The proposed sensor accurately estimated gabapentin concentration in commercial pharmaceutical formulations and spiked plasma samples, exhibiting excellent comparability with previously published methods. The 'greenness' of the sensing system was evaluated using the Analytical GREEnness calculator, revealing low environmental impact and strong alignment with green chemistry principles with a greenness score of 0.76. Thus, the developed N-CQDs-based sensor offers a promising, eco-friendly, and effective tool for gabapentin detection in various situations, ranging from clinical therapeutics to forensic science.

Can gabapentinoids decrease perioperative opioid requirements in orthopaedic trauma patients? A single-centre retrospective analysis

INTRODUCTION

Perioperative pain control in patients with orthopaedic trauma/extremity fractures has gained a lot of attraction from the scientific community in the last two decades. In addition to multimodal analgesia, the use of non-opioid drugs like gabapentinoids for pain relief is gradually finding its place in several orthopaedic subspecialties like spinal surgery, arthroplasty, and arthroscopic procedures. We envisage investigating the effectiveness of gabapentin in perioperative pain control in patients with extremity fractures undergoing surgical fixation.

METHODOLOGY

This was a retrospective comparative study conducted between January 2020 and January 2022. Patients with isolated fractures of the extremity involving long bones who were treated at our trauma centre, during the study period were divided into two groups based on the analgesics they received. Patients who received gabapentin and paracetamol were placed in group GP and those who received only paracetamol were assigned group NGP. Gabapentin was given in a single dose of 300 mg 4 h before surgery. Postoperatively, they were given 300 mg 12 hourly for 2 days. All patients in our trauma centre are usually managed with parenteral paracetamol administration pre and postoperatively. VAS score was calculated postoperatively at 2, 6, 12, 24 and 48 h. Patients requiring additional analgesics for pain relief were administered intravenous tramadol or a buprenorphine patch was applied. Patients in both groups were compared in terms of pain control, the additional requirement of opioid analgesics, and any adverse event related to medications.

RESULTS

One hundred and nineteen patients were enrolled in the study. Out of 65 patients in the NGP group (non-gabapentin group), 74% of patients received additional opioid analgesics apart from paracetamol. Out of the 54 patients in the GP group (gabapentin group), only 41% required additional opioid analgesia for pain control. There was a significant difference in opioid consumption between the two groups (p < 0.01). VAS scores were not significantly different between the two groups at 2, 4, 6, 12, 24 and 48 h. Gender and fracture morphology did not affect opioid intake in the GP group. However, in the non-gabapentin group, there was a significant difference in opioid requirement in patients with intraarticular fractures (p < 0.01).

CONCLUSION

Analgesic requirements vary from patient to patient depending on the injury's severity and surgery duration. However, there are no strict guidelines for pain relief in limb trauma surgeries which often leads to overuse and opioid-related complications or underuse and chronic pain. Gabapentinoids can supplement the analgesic effect of paracetamol in trauma patients during the perioperative period, decreasing the need for opioids.

Opioid-Sparing Pain Control after Rhinoplasty: Updated Review of the Literature

Rhinoplasty is one of the most performed elective surgeries, and given the opioid crisis, increasing research and studies are focused on successful pain control with multimodality opioid-sparing techniques, such as acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), and gabapentin. Although limiting overuse of opioids is critical, this cannot be at the expense of inadequate pain control, particularly as insufficient pain control can be correlated with patient dissatisfaction and the postoperative experience in elective surgery. There is likely significant opioid overprescription, as patients often report taking less than 50% of their prescribed opioids. Furthermore, excess opioids provide opportunities for misuse and opioid diversion if not disposed of properly. To optimize postoperative pain control and minimize opioid requirements, interventions must occur at the preoperative, intraoperative, and postoperative time points. Preoperative counseling is imperative to set expectations for pain and to screen for predisposing factors for opioid misuse. Intraoperatively, use of local nerve blocks and long-acting analgesia in conjunction with modified surgical techniques can lead to prolonged pain control. Postoperatively, pain should be managed with a multimodal approach, incorporating acetaminophen, NSAIDs, and potentially gabapentin with opioids reserved for rescue analgesia. Rhinoplasty represents a category of short-stay, low/medium pain, and elective procedures highly susceptible to overprescription and consequently, are readily amenable to opioid minimization through standardized perioperative interventions. Recent literature on regimens and interventions to help limit opioids after rhinoplasty are reviewed and discussed here.

Closing the Care Gap: Management of Alcohol Use Disorder in Patients with Alcohol-associated Liver Disease

Alcohol-associated liver disease (ALD)-related morbidity and mortality are rising in the United States. Although effective medications and behavioral interventions are available for the treatment of patients with alcohol use disorder (AUD), patients with ALD are profoundly undertreated for AUD. This article reviews the management of AUD in patients with ALD, with a focus on appropriate screening and diagnosis, management of alcohol withdrawal syndrome, pharmacotherapy for AUD, alcohol biomarkers, and behavioral interventions. Expanding access to AUD treatment is imperative for improving health outcomes in patients with ALD.

Effects of Acute and Chronic Gabapentin Treatment on Cardiovascular Function of Rats

Gabapentin (GBP), a GABA analogue, is primarily used as an anticonvulsant for the treatment of partial seizures and neuropathic pain. Whereas a majority of the side effects are associated with the nervous system, emerging evidence suggests there is a high risk of heart diseases in patients taking GBP. In the present study, we first used a preclinical model of rats to investigate, firstly, the acute cardiovascular responses to GBP (bolus i.v. injection, 50 mg/kg) and secondly the effects of chronic GBP treatment (i.p. 100 mg/kg/day × 7 days) on cardiovascular function and the myocardial proteome. Under isoflurane anesthesia, rat blood pressure (BP), heart rate (HR), and left ventricular (LV) hemodynamics were measured using Millar pressure transducers. The LV myocardium and brain cortex were analyzed by proteomics, bioinformatics, and western blot to explore the molecular mechanisms underlying GBP-induced cardiac dysfunction. In the first experiment, we found that i.v. GBP significantly decreased BP, HR, maximal LV pressure, and maximal and minimal dP/dt, whereas it increased IRP-AdP/dt, Tau, systolic, diastolic, and cycle durations (* p < 0.05 and ** p < 0.01 vs. baseline; n = 4). In the second experiment, we found that chronic GBP treatment resulted in hypotension, bradycardia, and LV systolic dysfunction, with no change in plasma norepinephrine. In the myocardium, we identified 109 differentially expressed proteins involved in calcium pathways, cholesterol metabolism, and galactose metabolism. Notably, we found that calmodulin, a key protein of intracellular calcium signaling, was significantly upregulated by GBP in the heart but not in the brain. In summary, we found that acute and chronic GBP treatments suppressed cardiovascular function in rats, which is attributed to abnormal calcium signaling in cardiomyocytes. These data reveal a novel side effect of GBP independent of the nervous system, providing important translational evidence to suggest that GBP can evoke adverse cardiovascular events by depression of myocardial function.

Involvement of the Spinal Serotonergic System in the Analgesic Effect of [6]-Shogaol in Oxaliplatin-Induced Neuropathic Pain in Mice

Oxaliplatin is a chemotherapy drug that can induce severe acute neuropathy in patients within hours of treatment. In our previous study, 10 mg/kg [6]-shogaol (i.p.) significantly alleviated cold and mechanical allodynia induced by a 6 mg/kg oxaliplatin injection (i.p.); however, the precise serotonin-modulatory effect has not been investigated. In this study, we showed that intrathecal injections of NAN-190 (5-HT1A receptor antagonist, 1 µg) and MDL-72222 (5-HT3 receptor antagonist, 15 µg), but not ketanserin (5-HT2A receptor antagonist, 1 µg), significantly blocked the analgesic effect of [6]-shogaol (10 mg/kg, i.p.). Furthermore, the gene expression of the serotonin-synthesizing enzyme tryptophan hydroxylase 2 (TPH2) and serotonin levels in the spinal cord and serum were significantly downregulated (p < 0.0001 and p = 0.0002) and upregulated (p = 0.0298 and p = 0.0099) after oxaliplatin and [6]-shogaol administration, respectively. Moreover, both the gene and protein expression of the spinal serotonin receptors 5-HT1A and 5-HT3 significantly increased after [6]-shogaol injections (p < 0.0001). Finally, intrathecal injections of both receptor agonists (8-OH-DPAT; 5-HT1A receptor agonist, 10 µg and m-CPBG; 5-HT3 receptor agonist, 15 µg) mimicked the effects of [6]-shogaol in oxaliplatin-injected mice. Taken together, these results demonstrate that [6]-shogaol attenuates oxaliplatin-induced neuropathic pain by modulating the spinal serotoninergic system.

Evaluation of Gabapentin as a Treatment of Breakthrough Cancer Pain Caused by Metastatic Prostate Adenocarcinoma

Introduction

Breakthrough Cancer Pain (BTcP) is defined as a temporary increase in pain that occurs spontaneously. The use of gabapentin is believed to be able to reduce pain complaints in patients with BTcP. However, research to support the efficacy of gabapentin in relieving pain in patients with BTcP is still limited. This study aims to determine the effectiveness of the use of gabapentin in patients with BTcP caused by metastatic prostate adenocarcinoma.

Methods

The study was conducted by analytic study with a prospective approach. The subjects were all patients with metastatic prostate adenocarcinoma at Zainoel Abidin General Hospital during 2022-2023 which fulfilled inclusion and exclusion criteria (30 patients). Data analysis was performed in the form of reduction in pain scale in patients with BTcP caused by metastatic prostate adenocarcinoma using gabapentin and the combination of the opioid gabapentin with T-Test.

Results

The results showed that there was no significant difference between the reduction in posttreatment pain in patients with BTcP caused by metastatic prostate adenocarcinoma taking gabapentin alone or taking the opioid gabapentin combination, either on days 3-4 or on days 5-6 (p > 0.05). However, based on the results of the evaluation on day 3-4, it was found that gabapentin was able to reduce pain by 2.2272, whereas the combination of opioid gabapentin was only able to reduce pain by 1.916. The evaluation on days 5-6 showed that gabapentin was able to reduce pain by 4.1363 and the combination of gabapentin opioids by 3.2083.

Conclusion

The conclusion of this research is that gabapentin is effective in the treatment of BTcP caused by metastatic prostate adenocarcinoma.

Pharmacokinetic, sedative, and physiological effects of oral compounded formulations of trazodone alone or in combination with gabapentin in male cats

Trazodone and gabapentin are common oral sedatives in cats, used alone or combined, but no pharmacokinetic studies exist for trazodone in this species. The objective of this study was to determine the pharmacokinetics of oral trazodone (T) alone, or in combination with gabapentin (G) in healthy cats. Cats (n = 6) were randomly allocated to receive T (3 mg/kg) intravenously (IV), T (5 mg/kg) orally (PO), or T (5 mg/kg) and G (10 mg/kg) PO with a 1-week washout period between treatments. Heart rate, respiratory rate, indirect blood pressure, and level of sedation were assessed, and venous blood samples were collected serially over 24 h. Analysis of plasma trazodone concentration was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Oral T administration resulted in a bioavailability of 54.9(7-96)%, and 17.2(11-25)% when administered with G. Tmax 0.17 (0.17-0.5) and 0.17 (0.17-0.75) h; Cmax 1.67 ± 0.91 and 1.22 ± 0.54 μg/mL, AUC 5.23 (2.0-18.76) and 2.37 (1.17-7.80) h*μg/mL; T1/2 5.12 ± 2.56 and 4.71 ± 1.07 h; for T and TG, respectively. Sedation was significant when compared to baseline in all groups from 20 or 45 min to 8 h indicating some lag between peak plasma concentration and sedative effects. Physiological variables remained within normal limits. This study concludes that oral trazodone is rapidly absorbed in healthy cats. Addition of gabapentin did not result in more profound sedation, showing no clinical advantage of combining these drugs in this study population.

Simultaneous application of lidocaine and ketamine during ambulatory infusion therapy: a retrospective analysis

Background: Infusions with lidocaine or ketamine have been separately established in the treatment of chronic pain. This study aims to retrospectively evaluate the effect of combined infusions of lidocaine and ketamine. Materials & methods: Patient records were screened for receipt of combined ambulatory infusions of lidocaine and ketamine from 2012 through 2021. A scoring system was designed to assess pain response retrospectively. Results: A total of 319 patients were included. Median pain reduction in days was 10.00 (interquartile range: 13.25). Side effects were limited to the acute phase of infusions. A total of 41.4% of patients who received concomitant pain medication reported a dose reduction. Conclusion: Our data support combined infusions as a safe therapy option, with good short-, medium- and long-term reductions in pain and great heterogeneity in treatment response. Clinical trial registration: ClinicalTrials.gov (NCT05103319).

Trigeminal Lipomatosis: A Rare Cause of Intractable Neuralgia

Lipomatosis of nerve, earlier known as fibrolipomatous hamartoma is a rare condition which predominantly affects peripheral nerves, cranial nerve involvement being extremely uncommon. Preoperative consideration of this entity is of paramount importance as its inadvertent complete surgical resection may inevitably result in significant neurological deficit. We report a case of trigeminal lipomatosis in a young patient with trigeminal neuralgia.

Association between chiropractic spinal manipulation and gabapentin prescription in adults with radicular low back pain: retrospective cohort study using US data

OBJECTIVES

Radicular low back pain (rLBP) is often treated off-label with gabapentin or by chiropractors using chiropractic spinal manipulative therapy (CSMT). To date, no studies have examined the association between these interventions. We hypothesised that adults under 50 years of age receiving CSMT for newly diagnosed rLBP would have reduced odds of receiving a gabapentin prescription over 1 year-follow-up.

DESIGN

Retrospective cohort study.

SETTING

US network including linked medical records, medical claims and pharmacy claims of >122 million patients attending large healthcare organisations (TriNetX), queried 15 June 2023, yielding data from 2017 to 2023.

PARTICIPANTS

Adults aged 18-49 were included at their first occurrence of rLBP diagnosis. Exclusions were severe pathology, other spinal conditions, on-label gabapentin indications and gabapentin contraindications. Propensity score matching controlled for variables associated with gabapentin use and receipt of prescription medication over the preceding year.

INTERVENTIONS

Patients were divided into CSMT or usual medical care cohorts based on the care received on the index date of rLBP diagnosis.

PRIMARY AND SECONDARY OUTCOME MEASURES

OR for gabapentin prescription.

RESULTS

After propensity matching, there were 1635 patients per cohort (mean age 36.3±8.6 years, 60% women). Gabapentin prescription over 1-year follow-up was significantly lower in the CSMT cohort compared with the usual medical care cohort, with an OR (95% CI) of 0.53 (0.40 to 0.71; p<0.0001). Sensitivity analyses revealed early divergence in cumulative incidence of prescription; and no significant between-cohort difference in a negative control outcome (gastrointestinal medication) suggesting adequate control for pharmacological care preference.

CONCLUSIONS

Our findings suggest that US adults receiving CSMT for newly diagnosed rLBP have significantly reduced odds of receiving a gabapentin prescription over 1-year follow-up compared with those receiving usual medical care. Results may not be generalisable and should be replicated in other healthcare settings and corroborated by a prospective study to reduce confounding.

GIP receptor agonism blocks chemotherapy-induced nausea and vomiting

OBJECTIVE

Nausea and vomiting remain life-threatening obstacles to successful treatment of chronic diseases, despite a cadre of available antiemetic medications. Our inability to effectively control chemotherapy-induced nausea and vomiting (CINV) highlights the need to anatomically, molecularly, and functionally characterize novel neural substrates that block CINV.

METHODS

Behavioral pharmacology assays of nausea and emesis in 3 different mammalian species were combined with histological and unbiased transcriptomic analyses to investigate the beneficial effects of glucose-dependent insulinotropic polypeptide receptor (GIPR) agonism on CINV.

RESULTS

Single-nuclei transcriptomics and histological approaches in rats revealed a topographical, molecularly distinct, GABA-ergic neuronal population in the dorsal vagal complex (DVC) that is modulated by chemotherapy but rescued by GIPR agonism. Activation of DVCGIPR neurons substantially decreased behaviors indicative of malaise in cisplatin-treated rats. Strikingly, GIPR agonism blocks cisplatin-induced emesis in both ferrets and shrews.

CONCLUSION

Our multispecies study defines a peptidergic system that represents a novel therapeutic target for the management of CINV, and potentially other drivers of nausea/emesis.

The association between Gabapentin or Pregabalin use and the risk of dementia: an analysis of the National Health Insurance Research Database in Taiwan

Objective: Previous studies have shown that gabapentin or pregabalin use is associated with cognitive decline. Herein, we aimed to evaluate the association between gabapentin or pregabalin use and the risk of dementia. Methods: In this retrospective, population-based matched cohort study, all research data were collected from the 2005 Longitudinal Health Insurance Database, which contains data of 2 million people randomly selected from the National Health Insurance Research Database of Taiwan in 2005. The study extracted data from 1 January 2000, to 31 December 2017. Adult patients taking gabapentin or pregabalin were included in the exposure group, and patients not using gabapentin or pregabalin matched to exposure subjects in a 1:5 ratio by propensity scores composed of age, sex and index date were included in the non-exposure group. Results: A total of 206,802 patients were enrolled in the study. Of them, 34,467 gabapentin- or pregabalin-exposure and 172,335 non-exposure patients were used for analysis. The mean follow-up day (±standard deviation) after the index date was 1724.76 (±1282.32) and 1881.45 (±1303.69) in the exposure and non-exposure groups, respectively; the incidence rates of dementia were 980.60 and 605.48 per 100,000 person-years, respectively. The multivariate-adjusted hazard ratio of risk of dementia for gabapentin or pregabalin exposure versus the matched non-exposed group was 1.45 (95% confidence interval [CI], 1.36-1.55). The risk of dementia increased with higher cumulative defined daily doses during the follow-up period. Moreover, the stratification analysis revealed that the risk of dementia associated with gabapentin or pregabalin exposure was significant in all age subgroups; however, it was higher in younger patients (age <50) than in the older patients (hazard ratio, 3.16; 95% CI, 2.23-4.47). Conclusion: Patients treated with gabapentin or pregabalin had an increased risk of dementia. Therefore, these drugs should be used with caution, particularly in susceptible individuals.

Provider-directed analgesia for dental pain

INTRODUCTION

Extraction of impacted molar teeth is a common procedure performed by oral surgeons and general dentists, with postoperative pain being a significant adverse event post-surgery. If mismanaged, pain can lead to complications that impact oral and systemic health. The current scourge of the opioid epidemic has ushered in a new era of provider-directed analgesic (PDA) therapy in dentistry.

AREAS COVERED

This article provides an in-depth review on the major pharmacological and therapeutic properties of established and alternative analgesics used to manage dental pain.

EXPERT OPINION

Substantial evidence-based literature shows combination of a non-steroidal anti-inflammatory drug (NSAID; e.g. ibuprofen) and acetaminophen provides superior pain relief than single-agent or combination opioid regimens. However, there are clinical scenarios (e.g. severe pain) when short-course opioid prescription is appropriate in select patients, in which a 2-3-day treatment duration is typically sufficient. Alternative agents (e.g. caffeine, gabapentin, phytotherapies), typically in combination with established agents, can mitigate postoperative dental pain. Some evidence suggests preemptive therapies (e.g. corticosteroids, NSAIDs) reduce amounts of postsurgical analgesic consumption and might lessen opioid prescription burden. In summary, this comprehensive review provides an opportune update on the evolving landscape of pharmacotherapy for acute postsurgical dental pain, informing best practices for PDA in the dental setting.

Efficacy of Prophylactic High-Dose Gabapentin and Venlafaxine on Reducing Oral Mucositis Pain Among Patients Treated With Chemoradiation for Head and Neck Cancer: A Single-Institution, Phase 2, Randomized Clinical Trial

PURPOSE

Given the paucity of level 1 evidence, the optimal regimen to control oral mucositis pain remains unclear. Although national guidelines allow consideration of prophylactic gabapentin, prior trials showed improved pain control with venlafaxine among patients with diabetic neuropathy. We sought to investigate the role of prophylactic high-dose gabapentin with venlafaxine to reduce oral mucositis pain among patients with head and neck cancer.

METHODS AND MATERIALS

We performed a single-institution, phase 2 randomized trial on nonmetastatic squamous cell carcinoma of the head and neck treated with chemoradiation. Patients were randomized to either prophylactic gabapentin (3600 mg daily) with or without venlafaxine (150 mg daily). Primary endpoint was differences in pain levels at the end of chemoradiation. Secondary endpoint was toxicity profiles, quality of life changes, opioid use, and feeding tube placement. Differences between the 2 arms at multiple time points were evaluated using a generalized linear mixed regression model with Sidak correction.

RESULTS

Between May 2018 and March 2021, a total of 62 patients were enrolled and evaluable for analysis (n = 32 for the gabapentin alone arm, n = 30 for the gabapentin + venlafaxine arm). Over 90% of patients tolerated gabapentin well. Head and neck pain level showed a mean value of 45 (standard deviation, 23) and 43 (standard deviation, 21) for the gabapentin alone and the gabapentin + venlafaxine arms, respectively (P = .65). No statistically significant differences were observed in adverse events, opioid use, feeding tube placement, or quality of life.

CONCLUSIONS

The addition of venlafaxine to prophylactic gabapentin did not result in improvements in pain control and quality of life among patients with head and neck cancer.

A Retrospective Study of the Adjunctive Use of Gabapentin With Benzodiazepines for the Treatment of Benzodiazepine Withdrawal

Benzodiazepine withdrawal is a widespread problem with potentially severe and deadly consequences. Currently, the only medications available for treating benzodiazepine withdrawal are short-acting and long-acting benzodiazepines. Identifying other drugs to help in treating benzodiazepine withdrawal is necessary. Gabapentin, an anxiolytic drug that is also used off-label to treat alcohol withdrawal, is a potential candidate for modulating benzodiazepine withdrawal. Using electronic records from a large inpatient psychiatric facility, a retrospective study of 172 patients presenting with benzodiazepine withdrawal was conducted to determine if the coincidental use of gabapentin for other medical conditions was associated with better outcomes of benzodiazepine withdrawal (N=57 gabapentin, N=115 no gabapentin). The primary outcomes were hospital length of stay and total amount of benzodiazepines given (lorazepam milligram equivalent). In this retrospective analysis of electronic medical record data, the patients experiencing benzodiazepine withdrawal who received gabapentin as an adjunct to the use of benzodiazepines were administered a smaller amount of benzodiazepines and had a shorter length of hospital stay relative to the comparison group who did not receive adjunctive gabapentin. These results suggest the potential use of gabapentin as an adjunct to the use of benzodiazepines for treating benzodiazepine withdrawal. The limitations of this study included a small sample size and variability in medication management strategies across the sample.

Early Optimized Pharmacological Treatment in Patients With Depression and Chronic Pain

Major depressive disorder (MDD) is the leading cause of disability worldwide. Patients with MDD have high rates of comorbidity with mental and physical conditions, one of which is chronic pain. Chronic pain conditions themselves are also associated with significant disability, and the large number of patients with MDD who have chronic pain drives high levels of disability and compounds healthcare burden. The management of depression in patients who also have chronic pain can be particularly challenging due to underlying mechanisms that are common to both conditions, and because many patients with these conditions are already taking multiple medications. For these reasons, healthcare providers may be reluctant to treat such patients. The Canadian Network for Mood and Anxiety Treatments (CANMAT) guidelines provide evidence-based recommendations for the management of MDD and comorbid psychiatric and medical conditions such as anxiety, substance use disorder, and cardiovascular disease; however, comorbid chronic pain is not addressed. In this article, we provide an overview of the pathophysiological and clinical overlap between depression and chronic pain and review evidence-based pharmacological recommendations in current treatment guidelines for MDD and for chronic pain. Based on clinical experience with MDD patients with comorbid pain, we recommend rapidly and aggressively treating depression according to CANMAT treatment guidelines, using antidepressant medications with analgesic properties, while addressing pain with first-line pharmacotherapy as treatment for depression is optimized. We review options for treating pain symptoms that remain after response to antidepressant treatment is achieved.

Detailed Kinetic and Mechanistic Study for the Preparation of Silver Nanoparticles by a Chemical Reduction Method in the Presence of a Neuroleptic Agent (Gabapentin) at an Alkaline pH and its Characterization

For the very first time, a detailed kinetic study for the preparation of silver nanoparticles (silver NPs) by neuroleptic agent gabapentin (GBP) in the absence of a stabilizer has been reported in this investigation. This paper is devoted to the preparation of silver nanoparticles by a chemical reduction method in which gabapentin acts as both a reductant and a stabilizer, and AgNO₃ is used as a source of Ag⁺ ions and NaOH for maintaining the alkaline medium. A UV-visible spectrophotometer is used to monitor the progress of the reaction kinetics in an aqueous medium by changing the concentration of different variables such as AgNO₃, NaOH, and gabapentin at 40 °C. It is found that the reaction rate follows a pseudo-first-order reaction. The thermodynamic activation parameters were also studied at five different temperatures (303, 308, 313, 318, and 323 K) and used in the support of the proposed mechanistic scheme for the formation of silver nanoparticles. The prepared silver nanoparticles were characterized using different techniques: UV-visible spectrophotometry, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and powder X-ray diffraction. The average particle size was observed in the range of 5-45 nm.

Drug Delivery Challenges in Brain Disorders across the Blood-Brain Barrier: Novel Methods and Future Considerations for Improved Therapy

Due to the physiological and structural properties of the blood-brain barrier (BBB), the delivery of drugs to the brain poses a unique challenge in patients with central nervous system (CNS) disorders. Several strategies have been investigated to circumvent the barrier for CNS therapeutics such as in epilepsy, stroke, brain cancer and traumatic brain injury. In this review, we summarize current and novel routes of drug interventions, discuss pharmacokinetics and pharmacodynamics at the neurovascular interface, and propose additional factors that may influence drug delivery. At present, both technological and mechanistic tools are devised to assist in overcoming the BBB for more efficient and improved drug bioavailability in the treatment of clinically devastating brain disorders.

Randomized Phase 3, Double-blind, Placebo-controlled Study of Prophylactic Gabapentin for the Reduction of Oral Mucositis Pain During the Treatment of Oropharyngeal Squamous Cell Carcinoma

PURPOSE

The purpose of this paper is to determine whether prophylactic gabapentin usage in patients undergoing definitive concurrent chemotherapy and radiation therapy (chemoRT) for oropharyngeal cancer (OPC) improves treatment-related oral mucositis pain, opioid use, and feeding tube (FT) placement.

METHODS AND MATERIALS

This double-blind, randomized phase 3 study for patients with locally advanced OPC undergoing chemoRT randomly allocated patients to prophylactic gabapentin (600 mg thrice daily) or placebo. The primary endpoint was change in Patient-Reported Oral Mucositis Symptom (PROMS) scores over the entire treatment period (baseline to 6 weeks post-radiation therapy [RT] follow-up) with higher scores indicating worse outcomes. Opioid requirements, FT placement, and other patient-reported quality of life (QOL) metrics (Functional Assessment of Cancer Therapy-Head and Neck [FACT-HN] and Patient-Reported Outcomes version of the National Cancer Institute Common Terminology Criteria for Adverse Events [PRO-CTCAE]) were assessed. Lower scores suggested poorer QOL with the FACT-HN questionnaire, and higher scores suggested worse outcomes with the PRO-CTCAE questionnaire. Questionnaires were administered at baseline, weekly during RT, and at 6 weeks post-RT follow-up. Repeated measures analysis of variance was used to detect differences in PROMS scores and change in opioid use from baseline. Wilcoxon rank sum tests were used to compare averages for the other secondary endpoints. A P value less than .05 was considered statistically significant.

RESULTS

Treatment arms were well balanced overall, including T and N staging and dosimetric variables. There were 58 patients analyzed. No significant difference was found in PROMS scores (mean 29.1, standard deviation [SD] 22.5 vs 20.1, SD 16.8 for gabapentin vs placebo, respectively, P = .11). The FACT-HN functional well-being index had a significant decrease in scores from baseline to follow-up in the gabapentin arm (median -6, interquartile range [IQR] -10.0 to -0.5 vs -1, IQR -5.5 to 3.0, P = .03). PRO-CTCAE scores increased significantly at follow-up for gabapentin (median 6.5, IQR 3.5-11.8 vs 1, IQR -2.0 to 6.0, P = .01). There was no significant difference in average or change in opioid use. FT placement was significantly higher in the gabapentin arm (62.1% vs 20.7%, P < .01).

CONCLUSIONS

This study suggests that prophylactic gabapentin is not effective in improving treatment-related oral mucositis symptoms in a select population of patients with OPC undergoing definitive chemoRT.

Consuming illicit opioids during a drug overdose epidemic: Illicit fentanyls, drug discernment, and the radical transformation of the illicit opioid market

BACKGROUND

North America continues to face an opioid overdose epidemic, driven by persistent increases in illicit fentanyls and fluctuations in potency leading to uncertainty for consumers. This qualitative study was conducted to better understand how people who inject drugs (PWID) came to recognize fentanyl as a growing adulterant of heroin and the subsequent sensory discernment strategies they employed to continue injecting. Our main objective was to investigate how observations and knowledge are combined as homegrown techniques for detecting fentanyl and minimizing risk. Secondary objectives were to examine the impact of growing fentanyl adulteration on individual drug use behavior.

METHODS

Between April and May 2019, 28 PWID (18 men, 10 women; average age = 38.43 years, SD = 9.26) were purposely recruited from a needle services program in Greensboro, North Carolina. Study participants were interviewed in-person using a qualitative, semi-structured instrument. Interviews were analyzed with a general inductive approach using NVivo12.

RESULTS

Participants described methods for detecting fentanyl in illicit opioids. Sudden increases in the potency of the 'rush' and sharp decreases in the length of the 'high' were chief indicators along with changes in drug color and texture. Heavy sedation was associated with fentanyl use and histamine-releasing effects characterized as 'pins and needles' were ascribed to injecting fentanyl as a component of the rush. Fentanyl's short high helped explain higher injection frequency and heavy sedation was the leading reason for co-using fentanyl with cocaine/crack or methamphetamine.

CONCLUSION

PWID have the capacity to recognize changes to the illicit opioid supply. Study participants navigated unpredictable fluctuations in the illicit opioid market by employing homegrown discernment techniques, modifying drug use behavior, and co-using non-opioid drugs. Researchers and policymakers should involve PWID as subject matter experts to help modernize harm reduction for the fentanyl age with practical strategies to boost resiliency and save lives.

Pharmacological evaluation of the gabapentin salicylaldehyde derivative, gabapentsal, against tonic and phasic pain models, inflammation, and pyrexia

Gabapentinoids are effective drugs in most animal models of pain and inflammation with variable effects in humans. The current study evaluated the pharmacological activity of gabapentin (GBP) and its salicylaldehyde derivative (gabapentsal; [2-(1-(((2-hydroxybenzylidene) amino) methyl) cyclohexyl) acetic acid]; GPS) in well-established mouse models of nociceptive pain, inflammatory edema, and pyrexia at doses of 25-100 mg/kg. GPS allayed tonic visceral pain as reflected by acetic acid-induced nociception and it also diminished thermally induced nociception as a mimic of phasic thermal pain. Antagonism of GPS-induced antinociceptive activities by naloxone (NLX, 1.0 mg/kg, subcutaneously, s.c), beta-funaltrexamine (β-FNT, 5.0 mg/kg, s.c), naltrindole (NT, 1.0 mg/kg, s.c), and nor-binaltorphimine (NOR-BNI, 5.0 mg/kg, s.c), and pentylenetetrazole (PTZ-15 mg/kg, intraperitoneally, i.p) implicated an involvement of both opioidergic and GABAergic mechanisms. Tail immersion test was conducted in order to delineate the mechanistic insights of antinociceptive response. Inflammatory edema induced by carrageenan, histamine, or serotonin was also effectively reversed by GPS in a fashion analogous to aspirin (150 mg/kg, i.p), chlorpheniramine (1.0 mg/kg, i.p), and mianserin (1.0 mg/kg, i.p), respectively. Additionally, yeast-induced pyrexia was decreased by GPS in a comparable manner to acetaminophen (50 mg/kg, i.p). These observations suggest that GPS possesses ameliorative properties in tonic, phasic, and tail immersion tests of nociception via opioidergic and GABAergic mechanisms, curbs inflammatory edema, and is antipyretic in nature.

Pharmacokinetic Drug-Drug Interactions among Antiepileptic Drugs, Including CBD, Drugs Used to Treat COVID-19 and Nutrients

Anti-epileptic drugs (AEDs) are an important group of drugs of several generations, ranging from the oldest phenobarbital (1912) to the most recent cenobamate (2019). Cannabidiol (CBD) is increasingly used to treat epilepsy. The outbreak of the SARS-CoV-2 pandemic in 2019 created new challenges in the effective treatment of epilepsy in COVID-19 patients. The purpose of this review is to present data from the last few years on drug–drug interactions among of AEDs, as well as AEDs with other drugs, nutrients and food. Literature data was collected mainly in PubMed, as well as google base. The most important pharmacokinetic parameters of the chosen 29 AEDs, mechanism of action and clinical application, as well as their biotransformation, are presented. We pay a special attention to the new potential interactions of the applied first-generation AEDs (carbamazepine, oxcarbazepine, phenytoin, phenobarbital and primidone), on decreased concentration of some medications (atazanavir and remdesivir), or their compositions (darunavir/cobicistat and lopinavir/ritonavir) used in the treatment of COVID-19 patients. CBD interactions with AEDs are clearly defined. In addition, nutrients, as well as diet, cause changes in pharmacokinetics of some AEDs. The understanding of the pharmacokinetic interactions of the AEDs seems to be important in effective management of epilepsy.

The ocular adverse effects of oral drugs

Some commonly prescribed drugs have ocular adverse effects. Many parts of the eye can be affected by oral drugs. Some ocular adverse effects may be reversed with medical or surgical intervention whereas other drugs may cause irreversible loss of vision

The risk of visual loss can be reduced by a number of approaches, including monitoring for ocular toxicity, reducing the drug dose, or stopping the drug and looking for an alternative. This can be supported by good communication between the prescribing clinician and ophthalmologist

Infrequent or delayed ocular adverse effects may not be identified in clinical trials of new drugs. Reporting adverse events is therefore important

Green Light Antinociceptive and Reversal of Thermal and Mechanical Hypersensitivity Effects Rely on Endogenous Opioid System Stimulation

Benefits of phototherapy were characterized in multiple diseases including depression, circadian rhythm disruptions, and neurodegeneration. Studies on migraine and fibromyalgia patients revealed that green light-emitting diodes (GLED) exposure provides a pragmatic and safe therapy to manage chronic pain. In rodents, GLED reversed hypersensitivity related to neuropathic pain. However, little is known about the underlying mechanisms of GLED efficacy. Here, we sought to understand how green light modulates the endogenous opioid system. We first characterized how exposure to GLED stimulates release of β-endorphin and proenkephalin in the central nervous system of male rats. Moreover, by individually editing each of the receptors, we found that µ- and δ-opioid receptors are required for green light's antinociceptive effect in naïve rats and a model of HIV-induced peripheral neuropathy. We investigated how GLED could increase pain thresholds, and explored its potential in reversing hypersensitivity in a model of HIV-related neuropathy. Through behavioral and gene editing approaches, we identified that green light provides antinociception via modulation of the endogenous opioid system in the spinal cord. This work identifies a previously unknown mechanism by which GLED can improve pain management. Clinical translation of these results will advance the development of an innovative therapy devoid of adverse effects. PERSPECTIVE: Development of new pain management therapies, especially for HIV patients, is crucial as long-term opioid prescription is not recommended due to adverse side effects. Green light addresses this necessity. Characterizing the underlying mechanisms of this potentially groundbreaking and safe antinociceptive therapy will advance its clinical translation.

Clinical Remission Using Personalized Low-Dose Intravenous Infusions of N-acetylcysteine with Minimal Toxicities for Interstitial Cystitis/Bladder Pain Syndrome

Interstitial Cystitis or Bladder Pain Syndrome (IC/BPS) is a heterogeneous condition characterized by elevated levels of inflammatory cytokines, IL-1β, IL-6, IL-8, IL-10, TNF-α, and is associated with debilitating symptoms of pelvic pain and frequent urination. A standard of care for IC/BPS has not been established, and most patients must undergo a series of different treatment options, with potential for severe adverse events. Here, we report a patient with a 26-year history of IC/BPS following treatment with multiple therapies, including low doses of etodolac, amitriptyline and gabapentin, which she was unable to tolerate because of adverse effects, including headaches, blurred vision and cognitive impairment. The patient achieved a complete clinical remission with minimal adverse events after 16 cycles of N-acetylcysteine (NAC) intravenous (IV) infusions over a period of 5 months, and pro-inflammatory cytokine levels were reduced when compared to measurements taken at presentation. Personalized low dose NAC IV infusion therapy represents an effective, safe, anti-inflammatory therapy administered in the outpatient setting for IC/BPS, and warrants further investigation.

Considerations for single- versus multiple-drug pharmacotherapy in the management of painful diabetic neuropathy

INTRODUCTION

The efficacy of monotherapy to reduce pain from diabetic peripheral neuropathy (DPN) is frequently not satisfactory and guidelines do not provide unanimous treatment options. In this context, multiple drug pharmacotherapy may provide benefit.

AREAS COVERED

The aim of the present review is to describe the clinical trials addressing the pharmacotherapy of painful DPN. Studies discussing efficacy and tolerability of pharmacological agents that were assessed in monotherapy and in combination treatment are reported and discussed.

EXPERT OPINION

Several clinical trials have reported benefit of multiple-drug pharmacotherapy. Nevertheless, untoward effects of combination treatment are of concern. Importantly, some trials were restricted to comparison with placebo and other compared only with active comparator(s). Only limited clinical trials assessed selected cohorts of individuals experiencing different stages of painful DPN. Despite current limitations, some evidence of studies implicating a comparison to all active comparators points to safety and effectiveness of the combination of oxycodone with pregabalin and that of pregabalin with the 5% lidocaine plaster but future, clear-cut studies are required to drive evidence-based decisions in the clinical setting.

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.

Vitamin E protects against gabapentin-induced chronic hepatic and renal damage associated with the inhibition of apoptosis and tissue injury in rats

AIMS

This study aimed to investigate the potential protective effects of vitamin E against gabapentin-induced chronic liver and kidney injury associated with the inhibition of biomarkers of apoptosis and tissue injury.

MATERIALS AND METHODS

Four groups of adult male rats were included; control, gabapentin (100 mg/kg/day), Vitamin E (80 mg/kg/day), and a combination of gabapentin and Vitamin E for 90 days. Serum levels of AST, ALT, LDH, ALP, urea, and creatinine were measured in addition to malondialdehyde (MDA), and reduced glutathione (GSH) tissue levels. P53 gene expression, histological, and immunohistochemical examinations were performed in liver and kidney tissue samples.

KEY FINDINGS

Gabapentin increased AST, ALT, LDH, ALP, urea, creatinine, MDA, and p53 gene expression and it reduced GSH. Moreover, gabapentin administration caused structural changes in the hepatic and renal architecture with a weak Periodic acid-Schiff (PAS) reaction that reflects glycogen deposition in the liver and kidney and a positive immunoreaction for BCL2-associated X protein (BAX) that reflects activated apoptosis. Vitamin E significantly (p<0.05) reversed the biochemical alterations associated with chronic gabapentin administration and improved the histopathological picture of hepatic and renal tissue with a partial inhibition of BAX.

SIGNIFICANCE

Chronic administration of gabapentin causes hepatic and renal impairments, which is ameliorated by Vitamin E; possibly due to the inhibition of biomarkers of apoptosis and tissue injury.

Quetiapine-Induced Place Preference in Mice: Possible Dopaminergic Pathway

Quetiapine, an atypical antipsychotic, is effective in the management of schizophrenia, depression, and anxiety. Although quetiapine overdosage and misuse have been reported, its abuse potential has not been investigated in animals. In this study, the abuse potential of quetiapine was assessed based on the conditioned place preference (CPP) paradigm of drug addiction in a mouse model. First, mice received intraperitoneal injections of quetiapine (40, 80, or 120 mg/kg) every other day during the conditioning phase. In the second experiment, mice were pretreated with 0.03 mg/kg SKF-35866, a D1 receptor antagonist, before receiving saline or quetiapine (120 mg/kg) during the conditioning phase. No significant changes in time spent in the quetiapine-paired chamber were observed compared with time spent in the saline-paired chamber in mice treated with 40 or 80 mg/kg. In contrast, the preference to the quetiapine-paired chamber was significantly increased in mice treated with 120 mg/kg quetiapine, and this effect was blocked by SKF-35866 pretreatment. These results demonstrated, for the first time, the abuse potential of quetiapine in an animal model of drug addiction. Interestingly, this CPP-inducing effect was likely mediated by activating D1 receptors.

Trends in unintentional polysubstance overdose deaths and individual and community correlates of polysubstance overdose, North Carolina, 2009-2018

BACKGROUND

Polysubstance involvement is increasing among fatal drug overdoses. However, little is known about the epidemiology of polysubstance drug overdoses. This paper describes emerging trends in unintentional polysubstance overdose deaths in North Carolina (NC) and examines associations with individual and community factors.

METHODS

Using 2009-2018 NC death certificate data, we identified unintentional drug overdose deaths and commonly involved substances (opioids, stimulants, benzodiazepines, alcohol, and antiepileptics). We examined polysubstance combinations, comparing opioid and non-opioid involved deaths. We examined individual level correlates from death certificate data and community level correlates from the American Community Survey and Robert Wood Johnson Foundation County Health Rankings to quantify associations.

RESULTS

From 2009-2018, 53 % of opioid and 19 % of non-opioid overdose deaths involved multiple substances. During this period, polysubstance overdose death increased dramatically, from 2.9 to 12.1 per 100,000 persons, with the greatest increases among drug combinations involving stimulants. The most common polysubstance combinations were: opioids and stimulants (12.1 % of overdose deaths); opioids and benzodiazepines (9.0 %); opioids and alcohol (5.1 %); opioids, stimulants, and benzodiazepines (3.1 %); and opioids, benzodiazepines, and antiepileptics (2.2 %). Compared to overdoses involving opioids alone, overdoses involving combinations of opioids, stimulants, and benzodiazepines involved younger individuals (53.7 % in 15-34 years of age vs. 40.7 %). Men comprised two-thirds of overdoses involving opioids alone, however, overdoses involving opioids, benzodiazepines, and antiepileptics were predominantly among women (60.6 %).

CONCLUSIONS

Polysubstance involvement has increased among overdose deaths in NC. These findings can be used to inform public health interventions addressing polysubstance deaths and associated individual and community level factors.

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

BACKGROUND

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

OBJECTIVE

Update previous SR and describe new insights regarding gabapentinoid abuse.

METHODS

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

RESULTS

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

CONCLUSION

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

New Methods Used in Pharmacokinetics and Therapeutic Monitoring of the First and Newer Generations of Antiepileptic Drugs (AEDs)

The review presents data from the last few years on bioanalytical methods used in therapeutic drug monitoring (TDM) of the 1st-3rd generation and the newest antiepileptic drug (AEDs) cenobamate in patients with various forms of seizures. Chemical classification, structure, mechanism of action, pharmacokinetic data and therapeutic ranges for total and free fractions and interactions were collected. The primary data on bioanalytical methods for AEDs determination included biological matrices, sample preparation, dried blood spot (DBS) analysis, column resolution, detection method, validation parameters, and clinical utility. In conclusion, the most frequently described method used in AED analysis is the LC-based technique (HPLC, UHPLC, USLC) combined with highly sensitive mass detection or fluorescence detection. However, less sensitive UV is also used. Capillary electrophoresis and gas chromatography have been rarely applied. Besides the precipitation of proteins or LLE, an automatic SPE is often a sample preparation method. Derivatization was also indicated to improve sensitivity and automate the analysis. The usefulness of the methods for TDM was also highlighted.

Median Nerve Stimulation as a Nonpharmacological Approach to Bypass Analgesic Tolerance to Morphine: A Proof-of-Concept Study in Mice

Analgesic tolerance to opioids contributes to the opioid crisis by increasing the quantity of opioids prescribed and consumed. Thus, there is a need to develop non-opioid-based pain-relieving regimens as well as strategies to circumvent opioid tolerance. Previously, we revealed a non-opioid analgesic mechanism induced by median nerve electrostimulation at the overlaying PC6 (Neiguan) acupoint (MNS-PC6). Here, we further examined the efficacy of MNS-PC6 in morphine-tolerant mice with neuropathic pain induced by chronic constriction injury (CCI) of the sciatic nerve. Daily treatments of MNS-PC6 (2 Hz, 2 mA), but not electrostimulation at a nonmedian nerve-innervated location, for a week post-CCI induction significantly suppressed established mechanical allodynia in CCI-mice in an orexin-1 (OX₁) and cannabinoid-1 (CB₁) receptor-dependent fashion. This antiallodynic effect induced by repeated MNS-PC6 was comparable to that induced by repeated gabapentin (50 mg/kg, i.p.) or single morphine (10 mg/kg, i.p.) treatments, but without tolerance, unlike repeated morphine-induced analgesia. Furthermore, single and repeated MNS-PC6 treatments remained fully effective in morphine-tolerant CCI-mice, also in an OX₁ and CB₁ receptor-dependent fashion. In CCI-mice receiving escalating doses of morphine for 21 days (10, 20 and 50 mg/kg), single and repeated MNS-PC6 treatments remained fully effective. Therefore, repeated MNS-PC6 treatments induce analgesia without tolerance, and retain efficacy in opioid-tolerant mice via a mechanism that involves OX₁ and CB₁ receptors. This study suggests that MNS-PC6 is an alternative pain management strategy that maybe useful for combatting the opioid epidemic, and opioid-tolerant patients receiving palliative care. PERSPECTIVE: Median nerve stimulation relieves neuropathic pain in mice without tolerance and retains efficacy even in mice with analgesic tolerance to escalating doses of morphine, via an opioid-independent, orexin-endocannabinoid-mediated mechanism. This study provides a proof of concept for utilizing peripheral nerve stimulating devices for pain management in opioid-tolerant patients.

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

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

Changes in Psychotropic Prescribing for Patients With Dementia, 2014-2016: Potential implications for Pharmacists

OBJECTIVE

To assess changes in psychotropic pharmacotherapy for patients with dementia over a three-year period.<br/> SETTING: National Ambulatory Medical Care Survey, physician office visits from 2014 to 2016.<br/> PRACTICE DESCRIPTION: Retrospective analysis of publicly available, nationally representative data on patient characteristics; diagnoses, including comorbidities; and treatments, including medications. Included were patients with a diagnosis of Alzheimer's disease or dementia who were 18 years of age or older. No sample exclusions were applied.<br/> INTERVENTION: Time period, comparing calendar year (CY) 2014 versus the calendar years 2015 and 2016 using Pearson chi-square tests.<br/> MAIN OUTCOME MEASURE(S): Prescribing rates of psychotropic medications, grouped by therapy class.<br/> RESULTS: The sample included 647 patients (337 in 2014 and 310 in 2015-2016). A majority (69.5%) of the patients were 75 years of age or older; 62.4% were female. Prescribing rates remained relatively stable for antipsychotics (15.1% in 2014 to 12.9% in 2015-16; P = 0.607); antidepressants (35.0% to 27.7%; P = 0.263); acetylcholinesterase inhibitors (38.6% to 33.9%; P = 0.446); and memantine (19.4% to 16.8%; P = 0.551). Significant increases were noted for sedatives (11.9% to 21.7%; P = 0.037) and anticonvulsants (10.0% to 27.6%, P = 0.001).<br/> CONCLUSION: Clinically significant increases in the prescribing of anticonvulsants and sedatives suggest the possibility that these agents are used to combat behavioral and psychological symptoms of dementia in patients with dementia. Further research is required to assess the rationale, efficacy, and safety of these uses.

Management of Insomnia and Anxiety in Myasthenia Gravis

Myasthenia gravis is a neuroimmunological disorder leading to skeletal muscle weakness. Common symptoms of the disease, such as anxiety, depression, and insomnia, can cause significant distress in patients. Unfortunately, selecting an appropriate medication for treatment of psychiatric comorbidities can prove to be challenging for providers given the unique pharmacologic constraints that myasthenia gravis presents. The authors present the following clinical vignette and accompanying discussion in an attempt to highlight the special considerations that must be taken into account when treating anxiety and insomnia in patients with myasthenia gravis, as well as to provide an overview of available medication options through the lens of existing constraints.

Gabapentin attenuates intestinal inflammation: Role of PPAR-gamma receptor

Gabapentin is an anticonvulsant drug that is also used for post-herpetic neuralgia and neuropathic pain. Recently, gabapentin showed anti-inflammatory effect. Nuclear factor kappa B (NFκB) is a regulator of the inflammatory process, and Peroxisome Proliferator-activated Receptor gamma (PPAR-gamma) is an important receptor involved in NFκB regulation. The aim of the present work was to study the potential role of PPAR-gamma receptor in gabapentin-mediated anti-inflammatory effects in a colitis experimental model. We induced colitis in rats using trinitrobenzenosulfonic acid and treated them with gabapentin and bisphenol A dicyldidyl ether (PPAR-gamma inhibitor). Macroscopic lesion scores, wet weight, histopathological analysis, mast cell count, myeloperoxidase, malondialdehyde acid, glutathione, nitrate/nitrite, and interleukin levels in the intestinal mucosa were determined. In addition, western blots were performed to determine the expression of Cyclooxygenase-2 (COX-2) and NFκB; Nitric Oxide Inducible Synthase (iNOS) and Interleukin 1 beta (IL-1β) levels were also determined. Gabapentin was able to decrease all inflammatory parameters macroscopic and microscopic in addition to reducing markers of oxidative stress and cytokines such as IL-1β and Tumor Necrosis Factor alpha (TNF-α) as well as enzymes inducible nitric oxide synthase and cyclooxygenase 2 and inflammatory genic regulator (NFκB). These effect attributed to gabapentin was observed to be lost in the presence of the specific inhibitor of PPAR-gamma. Gabapentin inhibits bowel inflammation by regulating mast cell signaling. Furthermore, it activates the PPAR-gamma receptor, which in turn inhibits the activation of NFκB, and consequently results in reduced activation of inflammatory genes involved in inflammatory bowel diseases.

Respiratory concerns of gabapentin and pregabalin: What does it mean to the pharmacovigilance systems in developing countries?

Gabapentin and pregabalin, commonly known as gabapentinoids, have been widely used globally. This paper highlights the serious breathing problems due to using gabapentin and pregabalin which was warned by the United States Food and Drug Administration on December, 2019. In this article, we tried to recommend suggestions for controlling these adverse drug reactions (ADRs). Safety reports of gabapentin and pregabalin should be obtained from concerned manufacturers and reviewed for respiratory depression effects. There should be strict prescription monitoring and drug use evaluation studies. Concurrent use of gabapentin and pregabalin with other respiratory depressants such as opioids should be strictly monitored. Educating patients can help in the early detection of ADRs due to gabapentin and pregabalin. Anecdotal reports on these medications should be encouraged.

Respiratory concerns of gabapentin and pregabalin: What does it mean to the pharmacovigilance systems in developing countries?

Gabapentin and pregabalin, commonly known as gabapentinoids, have been widely used globally. This paper highlights the serious breathing problems due to using gabapentin and pregabalin which was warned by the United States Food and Drug Administration on December, 2019. In this article, we tried to recommend suggestions for controlling these adverse drug reactions (ADRs). Safety reports of gabapentin and pregabalin should be obtained from concerned manufacturers and reviewed for respiratory depression effects. There should be strict prescription monitoring and drug use evaluation studies. Concurrent use of gabapentin and pregabalin with other respiratory depressants such as opioids should be strictly monitored. Educating patients can help in the early detection of ADRs due to gabapentin and pregabalin. Anecdotal reports on these medications should be encouraged.