Mechanism of action of alpha2delta ligands: voltage sensitive calcium channel (VSCC) modulators

Electrical stimulation induces anti-tumor immunomodulation via a flexible microneedle-array-integrated interdigital electrode

Immunotherapy has revolutionized cancer therapy, using chemical or biological agents to reinvigorate the immune system. However, most of these agents have poor tumor penetration and inevitable side effects that complicate therapeutic outcomes. Electrical stimulation (ES) is a promising alternative therapy against cancers that does not involve chemical or biological agents but is limited in the fabrication and operation of complex micrometer-scale ES devices. Here, we present an optically microprinted flexible interdigital electrode with a gold-plated polymer microneedle array to generate alternating electric fields for cancer treatment. A flexible microneedle-array-integrated interdigital electrode (FMIE) was fabricated by combining optical 3D microprinting and electroless plating processes. FMIE-mediated ES of cancer cells induced necrotic cell death through mitochondrial Ca2+ overload and increased intracellular reactive oxygen species (ROS) production. This led to the release of damage-associated molecular patterns that activated the immune response and potentiated immunogenic cell death (ICD). FMIE-based ES has an excellent safety profile and systemic anti-tumor effects, inhibiting the growth of primary and distant tumors as well as melanoma lung metastasis. FMIE-based ES-driven cancer immunomodulation provides a new pathway for drug-free cancer therapy.

Gabapentinoids: The rise of a new misuse epidemics?

Gabapentinoids and opioids have in common that they are used in medicine in the treatment of pain, and by addicts in recreational use. In recent years, in the context of the "opioid epidemics", gabapentinoids, which had a reputation for low risk of abuse, have been increasingly prescribed. This was accompanied by increasingly frequent abuses, the patients most at risk being those suffering from opiate addiction. However, gabapentinoids increase the risks associated with opioids or other sedatives, due to a synergy of central depressant effects. This leads to reconsider the framework of their prescription and the management of chronic pain.

Pilot randomized placebo-controlled clinical trial of high-dose gabapentin for alcohol use disorder

BACKGROUND

Despite advances in the development of pharmacotherapy for alcohol use disorder (AUD), there remains a need for medications that can be administered to actively drinking outpatients to promote a reduction in harmful alcohol consumption. The primary aim of this pilot study was to determine whether high-dose gabapentin (3600 mg/daily) is more effective than placebo in reducing harmful alcohol consumption in outpatients with AUD.

METHODS

Forty patients (27 men) who met DSM-IV-TR criteria for alcohol dependence and reporting at least 4 heavy drinking days (HDD) per week were recruited at a single site. Participants were actively drinking at study entry and received double-blind gabapentin (3600 mg/day; n = 19) or placebo (n = 20) for 8 weeks. Study medication was titrated over 5 days and administered in three divided doses (1200 mg three times per day). The proportion of HDD (primary outcome) and percent days abstinent (PDA; secondary outcome) were analyzed using generalized longitudinal mixed models with the predictors being study arm, week, study arm by week interaction, and corresponding baseline drinking measure.

RESULTS

There was a significant interaction between study arm and week for the proportion of HDD per week, F (7, 215) = 3.33, p = 0.002 . There was also a significant interaction between study arm and week for PDA per week, F (7, 215) = 3.11, p = 0.004. The overall retention rate was 67.5% with no significant difference in time-to-dropout between treatment groups. There were no serious adverse events. No participants were removed from the trial due to the development of moderate-to-severe alcohol withdrawal (CIWA-Ar ≥ 13).

CONCLUSIONS

Gabapentin treatment rapidly titrated to a dosage of 3600 mg/day is associated with a reduction in the proportion of HDD per week and an increase in PDA per week in actively drinking outpatients with AUD. High-dose gabapentin is potentially a feasible approach to treating AUD and deserving of further study.

An open-label pilot study of pregabalin pharmacotherapy for alcohol use disorder

Background: There is a need for alcohol use disorder (AUD) pharmacotherapy that can be administered to actively drinking outpatients. Pregabalin, a gabapentoid anticonvulsant, has preliminary evidence supporting effects on alcohol withdrawal and AUD.Objectives: To evaluate the safety, tolerability, and optimal dosing of pregabalin for treating AUD.Methods: In an open-label, 8-week, outpatient trial of eighteen adults (nine women) with AUD, participants were titrated to 600 mg/day (or the maximum tolerated dose) over 3 weeks and then maintained for 5 weeks.Results: The majority (11/14, 78.6%) of participants with at least one-week of medication exposure achieved a maximum dose of 600 mg/day. Mean retention was 6.8 weeks (SD = 2.6). Eighty percent (12/15) of participants with post-enrollment data reported any adverse effects during the trial; and for those reporting adverse effects the most common were drowsiness (33.3%, 4/12), and fogginess (25%, 3/12), dizziness (25%, 3/12), and insomnia (25%, 3/12). Two participants discontinued study medication due to adverse effects and one had a dose reduction. Mean Heavy Drinking Days (HDD)/week decreased significantly by 3.43 days (SD = 2.47; median (IQR) = 4.00 (1.00 to 5.50)); Wilcoxon signed rank test statistic ((S) = 49.5, p = .0006). Mean proportion of HDD significantly decreased on average by 48.7% (SD = 35.1%; median (IQR) = 57.1% (14.3% to 78.6%)). The proportion of abstinent days increased significantly on average by 36.1% (SD = 35.0%; median (IQR) = 17.9% (14.3% to 75.0%); S = 49.5, p = .0005).Conclusions: Pregabalin treatment of AUD appears to be safe and well tolerated in doses up to 600 mg per day.Trial Registration: clinicaltrials.gov identifier: NCT03256253.

'Z-trip'? A Comprehensive Overview and a Case-series of Zolpidem Misuse

Although believed safer compared to short-acting benzodiazepines (BZD), in the past few years a growing concern has developed relating to the abuse of Z-drugs, and specifically of zolpidem. Here we aim to review the evidence for the misuse of zolpidem and describe several related cases collected in Italy. A comprehensive overview is here carried by using several databases, and by combining the search strategy of free text terms and exploding a range of MESH headings relating to the topics of Zolpidem and Abuse and/or Misuse as follows: ((Zolpidem[Title/Abstract]) AND (Abuse[Title/Abstract]) OR (Misuse[Title/Abstract])), without time and/or language restrictions. Furthermore, a case series of 8 cases of zolpidem misuse and/or abuse, collected in different Italian psychiatric settings (psychiatric public hospital, psychiatric private rehabilitation clinic, and private practice), have been here described. According to our findings, zolpidem should be prescribed with the same caution as BZDs, especially in patients with a history of drug abuse or in the elderly. Behavioural modifications, including bizarre behaviours, psychomotor agitation, sleep-related complex behaviours have been reported. Monitoring of zolpidem use in selected populations is warranted. Psychiatrists and physicians should be aware of the misuse potential of zolpidem and adopt measures restricting its use.

Vocally disruptive behavior: A case report and literature review

Vocally disruptive behavior (VDB) is a common and particularly difficult symptom to manage in dementia. VDB is usually considered collectively with agitation and aggression as a component of behavioral and psychological symptoms in dementia and is therefore poorly understood as an individual symptom. A review of the literature is described where VDB as a challenging behavior has been individually examined as a symptom. A case of VDB occurring in patient with dementia is described where the patient's repetitive vocalizations responded to treatment with pregabalin. This has not been previously reported in the literature. The prevalence of VDB, the factors associated with it and the current management guidelines for clinicians are outlined with a review of the drug treatment strategies for VDB. Pregabalin with its unique pharmacological profile and excellent tolerability should be considered as a possible treatment for VDB where drug treatment is indicated.

Impact of Cachexia and Opioid Analgesic Cotreatment on Pregabalin Pharmacokinetics and Central Nervous System Symptoms in Cancer Patients

BACKGROUND

Patients with cancer receiving pregabalin potentially have a high incidence of central nervous system (CNS) symptoms. The purpose of this study was to explore clinical factors influencing the incidence of CNS symptoms, including plasma pregabalin exposure, cancer cachexia, and opioid analgesic cotreatment.

METHODS

Sixty-eight patients with cancer receiving twice-daily pregabalin were enrolled. Plasma concentrations of pregabalin, clinical laboratory data, opioid analgesic cotreatment, and the Glasgow Prognostic Score, which is an inflammation-based cachexia score, were considered as clinical factors. The incidence of CNS symptoms was collected from the patients' medical records. The predose plasma concentrations of pregabalin at steady state were determined by ultra-high-performance liquid chromatography.

RESULTS

The steady-state trough plasma pregabalin concentrations showed a large variability with an interquartile range of 0.43-1.2 mg/L per mg/kg and were negatively correlated with an estimated glomerular filtration rate (eGFR). C-reactive protein (standardized partial regression coefficient, β = 0.31) and opioid analgesic cotreatment (β = 0.24) were also identified in addition to eGFR (β = -0.60) in the multiple regression analysis. The incidence of CNS symptoms was significantly increased with opioid analgesic cotreatment and a higher Glasgow Prognostic Score but not with the absolute value of plasma pregabalin concentrations, eGFR, or other clinical laboratory data.

CONCLUSIONS

In patients with cancer, steady-state trough plasma pregabalin concentrations were altered with renal function, systemic inflammation, and opioid analgesic cotreatment. However, a higher incidence of CNS symptoms observed in patients with cancer on pregabalin was more related to cachexia and opioid analgesic cotreatment than to altered pregabalin concentrations.

Effects of Novel Calpain Inhibitors in Transgenic Animal Model of Parkinson's disease/dementia with Lewy bodies

Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are neurodegenerative disorders of the aging population characterized by the accumulation of α-synuclein (α-syn). The mechanisms triggering α-syn toxicity are not completely understood, however, c-terminus truncation of α-syn by proteases such as calpain may have a role. Therefore, inhibition of calpain may be of value. The main objective of this study was to evaluate the effects of systemically administered novel low molecular weight calpain inhibitors on α-syn pathology in a transgenic mouse model. For this purpose, non-tg and α-syn tg mice received the calpain inhibitors - Gabadur, Neurodur or a vehicle, twice a day for 30 days. Immunocytochemical analysis showed a 60% reduction in α-syn deposition using Gabadur and a 40% reduction using Neurodur with a concomitant reduction in c-terminus α-syn and improvements in neurodegeneration. Western blot analysis showed a 77% decrease in α-spectrin breakdown products (SBDPs) SBDPs with Gabadur and 63% reduction using Neurodur. There was a 65% reduction in the active calpain form with Gabadur and a 45% reduction with Neurodur. Moreover, treatment with calpain inhibitors improved activity performance of the α-syn tg mice. Taken together, this study suggests that calpain inhibition might be considered in the treatment of synucleinopathies.

Oral pregabalin for acute pain relief after cervicofacial surgery: a systematic review

OBJECTIVE

The objectives of this systematic review were to unify criteria on the effectiveness of oral pregabalin to treat acute post-operative pain after cervicofacial surgery, to establish the most effective dose regimens, and to determine its effect on rescue medicine consumption and its association with adverse effects.

MATERIALS AND METHODS

PubMed/Medline (National Library of Medicine, Washington, DC), Scopus, Web of Science, and Cochrane databases were searched for studies in any language published between January 2000 and September 2016. The following question was posed, in accordance with PRISMA guidelines: Is oral pregabalin effective and safe for the relief of acute pain after cervicofacial surgery? The critical reading of the literature utilized a list of questions prepared by the CASPe Network, applying the Jadad scale for evaluation of the methodological quality of trials.

RESULTS

Eleven randomized controlled clinical trials were selected. The 11 trials obtained a score ≥ 3, considered as Ib evidence level and high quality. A single oral dose of 75-mg pregabalin before or after cervicofacial surgery alleviates pain and lessens the need for rescue analgesia consumption, while the statistical significance of these effects is higher with a single dose of 150-mg pregabalin, either before or after the surgery.

CONCLUSION

Oral pregabalin appears to significantly alleviate post-operative pain and reduce rescue analgesia consumption, with no severe adverse effects. However, the ideal dose and most effective administration regimen remain controversial issues that need to be addressed in further high-quality clinical trials.

CLINICAL RELEVANCE

These findings suggest that pregabalin may be useful for acute pain relief after cervicofacial surgery.

Combination of gabapentin and ramosetron for the prevention of postoperative nausea and vomiting after gynecologic laparoscopic surgery: a prospective randomized comparative study

Background

As a drug originally introduced for its anticonvulsant effects, gabapentin has been recently shown to be effective in the treatment of nausea and vomiting in various clinical settings. This study compared the antiemetic efficacy of oral gabapentin, intravenous ramosetron and gabapentin plus ramosetron in patients receiving fentanyl-based patient-controlled analgesia after laparoscopic gynecologic surgery.

Methods

One hundred and thirty two patients undergoing laparoscopic gynecologic surgery under general anesthesia were allocated randomly into three groups: group G received 300 mg oral gabapentin 1 h before anesthesia, group R received 0.3 mg intravenous ramosetron at the end of surgery, and group GR received a combination of 300 mg oral gabapentin 1 h before anesthesia and 0.3 mg intravenous ramosetron at the end of surgery. Postoperative nausea, retching, vomiting, rescue antiemetic drug use, pain, rescue analgesic requirements and adverse effects were assessed at 0–2, 2–24 and 24–48 h after surgery. Postoperative nausea and vomiting (PONV) was defined as the presence of nausea, retching or vomiting.

Results

The incidence of complete response (no PONV and no rescue antiemetics up to 48 h postoperatively) was significantly higher in group GR (26/40, 65%) than group G (16/40, 40%; P = 0.025) and group R (18/44, 41%; P = 0.027), whereas there was no significant difference between group G and group R (P = 0.932). There were no significant between-group differences in the incidence of emetic episodes, use of rescue antiemetics, severe emesis, use of rescue analgesics or any adverse effects. Postoperative pain scores were also similar among groups.

Conclusions

The combination with gabapentin and ramosetron is superior to either drug alone for prevention of PONV after laparoscopic gynecologic surgery.

Trial registration

ClinicalTrials.gov NCT02617121, registered November 25, 2015.

Comparing Gabapentin with Clonazepam for Residual Sleeping Problems following Antidepressant Therapy in Patients with Major Depressive Disorder: A Randomized Clinical Trial

BACKGROUND AND OBJECTIVE

Residual sleeping disturbances after improvement of depression in major depressed patients are associated with more functional problems, increased relapses and more risk of becoming resistant to treatment. The aim of this study was to compare the efficacy of gabapentin with clonazepam for treating residual sleeping disturbances.

METHODS

This comparative trial was designed as a randomized, controlled, double-blind study. Sixty-three patients with a DSM-IV diagnosis of major depressive disorder (MDD) who had been treated with one of the selective serotonin reuptake inhibitors (SSRIs; fluoxetine, citalopram or sertraline) were included in the study. The patients' depression had improved [Hamilton Depression Rating Scale (HDRS) <10] but they were complaining of sleeping problems [Pittsburgh Sleep Quality Index (PSQI) >5; Insomnia Severity Index (ISI) >8]. Patients were randomized to receive a flexible dose of gabapentin (100-600 mg/day) or clonazepam (0.5-2 mg/day) beside their current antidepressant medication for a period of 4 weeks. Outcome measures were PSQI, ISI and Clinical Global Impression (CGI).

RESULTS

Our results demonstrated that similar to the clonazepam group, sleeping problems improved significantly in the gabapentin group at the end of the trial (PSQI: P = 0.001, Z = 3.549; ISI: P = 0.001, Z = 3.347). The two groups did not show a significant difference in treating residual sleep disturbances (PSQI: P = 0.234, Z = 1.432; ISI: P = 0.456, Z = 1.347).

CONCLUSION

This study revealed that gabapentin is comparable to clonazepam for treating sleeping problems associated with major depression.

The Effect of Preoperative Gabapentin on Postoperative Nausea and Vomiting: A Meta-Analysis

BACKGROUND

Preoperative gabapentin has been shown to improve postoperative pain and limit reliance on opioid analgesia. On the basis of an alternative mechanism, our group investigated the ability of preoperative gabapentin to prevent postoperative nausea and vomiting (PONV).

METHODS

We performed a meta-analysis of trials that reported outcomes on the effect of preoperative gabapentin on PONV end points in patients undergoing general anesthesia. In our primary analysis, we calculated the pooled antiemetic effects of preoperative gabapentin in studies with PONV as the primary end point. In our secondary analysis, we calculated the pooled effects in trials involving preoperative gabapentin that reported on the side effects, nausea and vomiting.

RESULTS

Among the trials designed with PONV as a primary end point (8 trials; n = 838), preoperative gabapentin was associated with a significant reduction in PONV (risk ratio [RR] = 0.60; 99% confidence interval [CI], 0.50-0.72; P < 0.0001), nausea (RR = 0.34; 99% CI, 0.20-0.56; P < 0.0001), and vomiting (RR = 0.34; 99% CI, 0.19-0.61; P = 0.0002) at 24 hours. Among all included trials (44 trials; n = 3489) that reported on the side effects, nausea and vomiting, similar reductions were noted in PONV with preoperative gabapentin administration. Subgroup analysis of trials excluding repeat dosing, thiopental induction, and nitrous oxide maintenance and including high-risk surgery resulted in similar PONV efficacy. Preoperative gabapentin is also associated with significantly increased rates of postoperative sedation (RR = 1.22; 95% CI, 1.02-1.47; P = 0.03) compared with control.

CONCLUSIONS

Preoperative gabapentin is associated with a significant reduction in PONV among studies designed to investigate this end point. Preoperative gabapentin should be considered not only as part of a multimodal approach to postoperative analgesia, but also for prevention of PONV.

Gabapentin prophylaxis for postoperative nausea and vomiting in abdominal surgeries: a quantitative analysis of evidence from randomized controlled clinical trials

INTRODUCTION

Postoperative nausea and vomiting (PONV) is frequently encountered in the surgical recovery room. Abdominal surgery is one important risk factor for increased incidence of PONV. Gabapentin, an anticonvulsant with known postoperative analgesic properties, has shown some activity against PONV. Results from clinical trials evaluating the anti-emetic efficacy of gabapentin are conflicting. The present meta-analysis was performed to examine this issue.

METHODS

Seventeen randomized placebo-controlled trials reporting PONV with preoperative gabapentin administration in patients undergoing abdominal surgery were included for analysis. Outcomes evaluated were nausea, vomiting, composite PONV and the use of rescue anti-emetic medication in the postoperative period.

RESULTS

The pooled relative risk (RR), estimated using the random effects model of the metafor package for R, was 0.76 (95% CI 0.58-0.98) for nausea, 0.62 (0.45-0.85) for vomiting, 0.71 (0.39-1.28) for data represented as composite PONV (possibly biased by a single study, as observed in the sensitivity analysis), and 0.6 (0.41-0.89) for rescue anti-emetic use. There was a significant RR reduction for nausea and vomiting when propofol was not used as induction and/or maintenance for anaesthesia. In the abdominal hysterectomy subgroup, there was a significant RR reduction for vomiting but not for nausea.

DISCUSSION

The present analysis provides evidence supporting preoperative gabapentin as a pharmacotherapy for prevention of PONV in patients undergoing abdominal surgeries. Future studies comparing preoperative gabapentin with 5HT3 antagonists are needed to precisely define its role in PONV.

Pregabalin for the management of neuropathic pain in spinal cord injury

SUMMARY Pregabalin is the only US FDA-approved drug to date for neuropathic pain in spinal cord injured patients. Pregabalin is a novel GABA analog whose primary mechanism of action involves binding at the α2-δ subunit of voltage-sensitive calcium channels. Efficacy is noted within the first several days of administration. Dosing is typically initiated at 150 mg/day in divided doses, but may be started at even lower doses. Dosing can be increased gradually to a recommended maximum of 600 mg per day in divided dosing. Adverse events include somnolence, dizziness and dry mouth, and typically manifest within the first 2 weeks of treatment. Pregabalin is generally safe to use in combination with other pain medications or antidepressants, but safety in pregnant patients has not been established.

Epilepsy, cognition, and neuropsychiatry (Epilepsy, Brain, and Mind, part 2)

Epilepsy is, of course, not one disease but rather a huge number of disorders that can present with seizures. In common, they all reflect brain dysfunction. Moreover, they can affect the mind and, of course, behavior. While animals too may suffer from epilepsy, as far as we know, the electrical discharges are less likely to affect the mind and behavior, which is not surprising. While the epileptic seizures themselves are episodic, the mental and behavioral changes continue, in many cases, interictally. The episodic mental and behavioral manifestations are more dramatic, while the interictal ones are easier to study with anatomical and functional studies. The following extended summaries complement those presented in Part 1.

Pregabalin- and topiramate-mediated regulation of cognitive and motor impulsivity in DBA/2 mice

BACKGROUND AND PURPOSE

Impulsivity is a core symptom in many neuropsychiatric disorders. The main objective of this study was to evaluate the effects of topiramate and pregabalin on the modulation of different impulsivity dimensions in DBA/2 mice.

EXPERIMENTAL APPROACH

The effects of acute and chronic administration of pregabalin (10, 20 and 40 mg·kg(-1) ) and topiramate (12.5, 25 and 50 mg·kg(-1) ) were evaluated in the light-dark box (LDB), hole board test (HBT) and delayed reinforcement task (DRT). α(2A) -Adrenoceptor, D(2) -receptor and TH gene expression were evaluated by real-time PCR in the prefrontal cortex (PFC), accumbens (ACC) and ventral tegmental area (VTA), respectively.

KEY RESULTS

Acute pregabalin administration showed a clear anxiolytic-like effect (LDB) but did not modify novelty-seeking behaviour (HBT). In contrast, topiramate produced an anxiolytic effect only at the highest dose, whereas it reduced novelty seeking at all doses tested. In the DRT, acute pregabalin had no effect, whereas topiramate only reduced motor impulsivity. Chronically, pregabalin significantly increased motor impulsivity and topiramate diminished cognitive impulsivity. Pregabalin decreased α(2A) -adrenoceptor and D(2) -receptor gene expression in the PFC and ACC, respectively, and increased TH in the VTA. In contrast, chronic administration of topiramate increased α(2A) -adrenoceptor and D(2) -receptor gene expression in the PFC and ACC, respectively, and also increased TH in the VTA.

CONCLUSIONS AND IMPLICATIONS

These results suggest that the usefulness of pregabalin in impulsivity-related disorders is related to its anxiolytic properties, whereas topiramate modulates impulsivity. These differences could be linked to their opposite effects on α(2A) -adrenoceptor and D(2) -receptor gene expression in the PFC and ACC, respectively.

Effects of anxiolytic treatment on potentiated startle during aversive image anticipation

OBJECTIVE

Heightened anticipation of future events has been characterized as a feature of certain anxiety disorders. In functional magnetic resonance imaging studies, anticipation of fearful/threatening images has been shown to robustly activate the insular cortex and amygdala in healthy subjects, in subjects with high trait anxiety, and in some with anxiety disorders. Blood oxygenation level dependent activation in response to negative image anticipation is also sensitive to anxiolytic treatment, suggesting that image anticipation probes anxiety systems. It is not clear, however, if behavioral responses to image anticipation are also sensitive to anxiolytics. This study tested the hypothesis that anxiety behaviors during anticipation of negative images are sensitive to anxiolytic treatment.

METHOD

This study examined the effects of alprazolam and pregabalin treatment on potentiated startle during affective image anticipation.

RESULTS

There was an effect of anticipation type (negative versus neutral versus positive) on startle reactivity and subjective ratings, suggesting that the task was effective in assaying negative anticipatory arousal. Both treatments significantly reduced overall startle magnitude. However, neither treatment specifically affected potentiated startle during aversive anticipation.

CONCLUSION

These data suggest that potentiated startle in response to anticipation of aversive images is not sensitive to anxiolytic treatments in a healthy population, limiting its use as a predictive model of anxiolytic activity. This article is a US Government work and is in the public domain in the USA.

Efficacy and safety of pregabalin in the treatment of alcohol withdrawal syndrome: a randomized placebo-controlled trial

AIMS

The objective of this study was to collect preliminary data on the efficacy and safety of pregabalin in attenuating the severity of alcohol withdrawal symptoms during detoxification treatment in alcohol dependence.

METHODS

Forty-two alcohol-dependent patients with an alcohol withdrawal syndrome (AWS) were included in the prospective randomized double-blind placebo-controlled trial during inpatient alcohol detoxification. For 6 days, participants either received pregabalin or placebo according to a fixed dose schedule starting with 300 mg/day. Depending on the score of the AWS Scale (AWSS), diazepam was additionally administered as a rescue medication. The primary endpoint was the total amount of diazepam required from Day 2 to 6 of detoxification treatment in each of the two groups. Secondary outcome variables were the difference in AWSS and Clinical Institute Withdrawal Assessment for Alcohol (CIWA-Ar) scores between Day 2 and 6, tolerability and safety data, drop-out rates as well as changes in the neuropsychological scales.

RESULTS

Pregabalin and placebo were equally safe and well tolerated. However, no statistically significant difference was found comparing the total amount of additional diazepam medication required in the two study groups. Pregabalin and placebo also showed similar efficacy according to alterations of scores of the AWSS, CIWA-Ar and neuropsychological scales. The frequency of adverse events and drop-outs did not differ between the both treatment groups.

CONCLUSIONS

The study demonstrates the relative safety of pregabalin in the treatment of AWS. However, the results do not provide evidence in favor of pregabalin compared with placebo concerning its efficacy in the treatment of AWS.

A meta-analysis of the efficacy of pregabalin in the treatment of generalized anxiety disorder

OBJECTIVE

Generalized anxiety disorder (GAD) is a chronic anxiety disorder that leads to significant functional impairment and reduced quality of life. Pregabalin is a novel analogue of the inhibitory neurotransmitter gamma amino butyric acid, which has been proposed as a treatment for a range of conditions including GAD. This study examined the efficacy of pregabalin for GAD across published trials, using a meta-analytic method.

METHOD

This study examined the 7 published placebo-controlled trials of GAD using pregabalin, and, using meta-analytic techniques, we calculated the effect size of treatment with pregabalin (compared with placebo) on a total of 1352 people.

RESULTS

The overall effect size of pregabalin in the treatment of GAD was Hedges' g = 0.364, with an effect size of 0.349 on psychic anxiety symptoms and of 0.239 on somatic anxiety symptoms.

CONCLUSION

Pregabalin is an efficacious therapy for GAD, although effect sizes are smaller than those from earlier studies. Limitations and future research directions are discussed.

Pregabalin in zolpidem dependence and withdrawal

Several recent reports attest to zolpidem's strong potential for abuse, dependence, and severe withdrawal symptoms upon its discontinuation. We report, for the first time, on 1 case of heavy zolpidem abuse and dependence with severe withdrawal symptoms twice treated safely and successfully with pregabalin, a newer antiepileptic agent devoid of known strong potential for abuse and dependence.

Part 2: Design, synthesis and evaluation of hydroxyproline-derived α2δ ligands

Conformational constraint has been used to design a potent series of α(2)δ ligands derived from the readily available starting material (2S,4R)-hydroxy-l-proline. The ligands have improved physicochemistry and potency compared to their linear counterparts (described in our earlier publication) and the lead compound has been progressed to clinical development.

Akathisia Induced by Gabapentin Withdrawal

OBJECTIVE:

To report a case of akathisia in a patient with type 2 diabetes after abrupt discontinuation of gabapentin.

CASE SUMMARY:

A 76-year-old female with type 2 diabetes was admitted for change in mental status, agitation, and restless limb movements. She had been taking gabapentin 3600 mg daily for approximately 1 month for diabetic neuropathy. Her other home medications were glyburide 10 mg twice daily, oxycodone/acetaminophen 5 mg/325 mg every 6 hours as needed for leg pain, and zolpidem 5 mg at bedtime. She had taken none of these drugs for 4 days prior to admission because she was unable to have the prescriptions refilled. Subsequently, the patient exhibited repeated arm and leg motions in response to an inner restlessness. Upon admission to the emergency department, she was agitated and restless; all vital signs and results of laboratory studies were within normal limits. Gabapentin was restarted at the original dosage and the symptoms resolved within 8 hours. Because the patient developed lethargy, the gabapentin dosage was reduced and titrated to the original level over 2 days. After 3 days, the patient was well oriented and experienced no further symptoms. She was discharged on the original dosage of gabapentin.

DISCUSSION:

To our knowledge, this is the first reported cases of akathisia induced by gabapentin withdrawal. Available case reports suggest that gabapentin withdrawal can occur at doses ranging from 400-8000 mg/day. Patients experienced symptoms similar to those that develop with benzodiazepine withdrawal and were taking gabapentin for as little as 3 weeks to as long as 5 years. This is the first case report to describe akathisia induced by gabapentin withdrawal. The Naranjo probability scale revealed a probable relationship between akathisia and gabapentin withdrawal.

CONCLUSIONS:

If gabapentin discontinuation is desired, it is prudent to gradually taper the dose to avoid withdrawal symptoms, which may occur after as little as 1 month of treatment. Should the patient experience withdrawal symptoms, the optimal treatment is to restart gabapentin.

Effective dose of peri-operative oral pregabalin as an adjunct to multimodal analgesic regimen in lumbar spinal fusion surgery

STUDY DESIGN

A prospective, randomized, controlled, and double-blind trial.

OBJECTIVE

To evaluate the effects of 2 different doses of perioperative pregabalin administration, twice on the day of surgery, on acute postoperative pain after spinal surgery.

SUMMARY OF BACKGROUND DATA

Besides its well-established role on neuropathic pain, pregabalin seems to be a promising adjunct to multimodal analgesic regimen following surgery. No comprehensive data exist regarding the optimal dosage of pregabalin on reducing postoperative pain and opioid consumption in spinal surgery.

METHODS

Patients were randomly assigned to 1 of 3 groups. The placebo group (n = 28) received placebo capsules 1 hour before the anesthetic induction and 12 hours after surgery. The pregabalin groups received pregabalin 75 mg (P75 group, n = 28) or 150 mg (P150 group, n = 28), respectively at the same points. Assessed variables were total amount of administered fentanyl-based intravenous patient-controlled analgesia, pain intensity, and the frequency of rescue analgesic administered during the first 48 hours after surgery, subdivided into the following 4 periods: on arrival of patient to the postanesthesia care unit, 1 to 6 hours, 6 to 24 hours, and 24 to 48 hours. RESULTS.: The amount of patient-controlled analgesia volume infused until 24 hours (P 5 0.025) and 48 hours (P 5 0.028) after surgery was significantly less in the P150 group compared with the control group. The frequency of additional anodynes administered until 6 hours (P 5 0.049) and 24 hours (P 5 0.045) after surgery was significantly less in the P150 group compared with the control group.

CONCLUSION

Perioperative administration of pregabalin 150 mg before and 12 hours after surgery, but not 75 mg, significantly reduced opioid consumption and the use of additional pain rescue for 48 hours after surgery without significant side effects in patients undergoing spinal fusion surgery.

Pregabalin in the treatment of alcohol and benzodiazepines dependence

We review all available studies on the use of the newer anticonvulsant drug pregabalin (PGB) in the treatment of both alcohol dependence (AD) and benzodiazepine dependence (BD). In AD, the available evidence includes one open-label and one double-blind randomized studies, whereas in BD, only a few case reports and one open-label study are as yet available. In both conditions, PGB was found efficacious with significant improvement in withdrawal symptoms at the dosage ranges of 150-450 mg/day (AD) and 225-900 mg/day (BD). Moreover, its side effects were mild and transient. Despite the limited quality of the studies design, their findings suggest that PGB might constitute a novel efficacious and safe option in the treatment of both AD and BD.

Synthesis and in vivo evaluation of 3-substituted gababutins

A range of 3-alkylated five-membered ring derivatives of Gabapentin were synthesized and several were found to have good levels of potency against the alpha2delta calcium subunit of a voltage-gated calcium channel. Two compounds were profiled in in vivo models of pain and anxiety.

Gabapentin-induced delirium and dependence

Gabapentin (Neurontin) is approved by the US Food and Drug Administration for treatment of epilepsy and post-herpetic neuralgia. Despite lack of strong evidence, gabapentin is also often prescribed off-label for psychiatric conditions. The case described here involved a 38-year-old male physician with substance intoxication delirium and psychoactive substance dependence due to high self-administered doses of gabapentin, which had been prescribed at lower doses in combination with buspirone and bupropion for depression and anxiety. This unusual case of gabapentin dependence and abuse involved toxic delirium, intense cravings, and a prolonged post-withdrawal confusional state reminiscent of benzodiazepine withdrawal. Gabapentin is a central nervous system inhibitory agent with likely gamma-aminobutyric acid (GABA)-ergic and non-GABAergic mechanisms of action. The similarity between benzodiazepine withdrawal and what this patient experienced with gabapentin suggests a common role for GABA-related effects. The case reported here suggests the need for heightened concern regarding the off-label prescription of this drug to vulnerable individuals with psychiatric conditions.

Validating a human model for anxiety using startle potentiated by cue and context: the effects of alprazolam, pregabalin, and diphenhydramine

BACKGROUND

Fear-potentiated startle has been suggested as a translational model for evaluating efficacy of anxiolytic compounds in humans. Several known anxiolytic compounds have been tested as well as several putative anxiolytics. Because results of these studies have been equivocal, the aim of the present study was to examine another pharmacological permutation of the human potentiated startle model by comparing two anxiolytic agents to a non-anxiolytic sedative and placebo.

METHODS

Twenty healthy volunteers participated in a double-blind, placebo-controlled, cross-over study with four sessions in which they received single doses of the anxiolytics alprazolam (1 mg) and pregabalin (200 mg), as well as diphenhydramine (50 mg) as a non-anxiolytic sedative control and placebo. The design included a cued shock condition that presumably evokes fear and an unpredictable shock context condition presumably evoking anxiety.

RESULTS

None of the treatments reliably reduced either fear- or anxiety-potentiated startle. Alprazolam and diphenhydramine reduced overall baseline startle. Alprazolam was found to only affect contextual anxiety in a statistical significant way after two subjects who failed to show a contextual anxiety effect in the placebo condition were excluded from the analysis. Pregabalin did not significantly affect any of the physiological measures.

DISCUSSION

The negative findings from this study are discussed in terms of methodological differences between designs and in variability of startle both between and within study participants.

CONCLUSION

Even though fear-potentiated startle may be used to translate preclinical evidence to human populations, methodological issues still hamper the application of this model to early screening of putative anxiolytic drugs.

Efficacy and tolerability of pregabalin in partial epilepsy

Pregabalin, the most recently approved antiepileptic drug, is a structural analog of GABA with a favorable pharmacokinetic profile. Pregabalin binds to the alpha2-delta subunit of a neuronal voltage-gated calcium channel and is believed to exert its anticonvulsant effect by modulating the release of specific neurotransmitters from hyperexcited presynaptic neurons. Animal models of epilepsy have suggested that this drug will be efficacious against partial-onset and generalized tonic-clonic seizures. Four pivotal, add-on clinical trials conducted in patients with partial-onset seizures demonstrated that pregabalin at daily doses of 150-600 mg is efficacious and associated with dose-dependent adverse events. Meta-analyses of efficacy and tolerability indicated that pregabalin is an efficacious and relatively well-tolerated antiepileptic drug.

Enriched enrollment: definition and effects of enrichment and dose in trials of pregabalin and gabapentin in neuropathic pain. A systematic review

AIMS

Enriched enrollment study designs have been suggested to be useful for proof of concept when only a proportion of the diseased population responds to a treatment intervention. We aim to investigate whether this really is the case in trials of pregabalin and gabapentin in neuropathic pain.

METHODS

We defined 'complete', 'partial' and 'non-enriched' enrollment, and examined pregabalin and gabapentin trials for the extent of enrichment and for effects of enrichment on efficacy and adverse event outcomes.

RESULTS

There were no studies using complete enriched enrollment; seven trials used partial enriched enrollment and 14 non-enriched enrollment. In pregabalin trials the maximum extent of enrichment was estimated at about 12%. Partial enriched enrollment did not change estimates of efficacy or harm. Over 150-600 mg maximum daily dose there was strong dose dependence for pregabalin.

CONCLUSIONS

A benefit of partial over non-enriched enrollment could not be demonstrated because the degree of enrichment was rather small, and possibly because enrichment produced little enhancement of treatment effect. Whether a greater degree of enrichment would result in important differences is unknown. Researchers reporting clinical trials with any enrichment must describe both process and extent of enrichment. As things stand, the effects of enriched enrollment remain unknown for neuropathic pain trials.

A randomized double-blind pilot trial of gabapentin versus placebo to treat alcohol dependence and comorbid insomnia

BACKGROUND

Insomnia and other sleep disturbances are common, persistent, and associated with relapse in alcohol-dependent patients. The purpose of this pilot study was to compare gabapentin versus placebo for the treatment of insomnia and prevention of relapse in alcohol-dependent patients.

METHODS

Twenty-one subjects, including 10 women who met study criteria for alcohol dependence and insomnia and expressed a desire to abstain from alcohol, were recruited to the study. During a 1 to 2 week placebo lead-in and screening phase, a complete medical history, physical exam, blood tests, urine drug test, and structured interviews were performed to determine eligibility and patterns of alcohol use and sleep. Insomnia due to intoxication or acute withdrawal, psychiatric or medical illness, medications, and other sleep disorders were ruled out. Subjects were then randomized to either placebo (n = 11) or gabapentin (n = 10) for 6 weeks and titrated over a 10-day period to 1,500 mg or 5 pills at bedtime. After a 4-day taper, subjects were reassessed 6 weeks after ending treatment.

RESULTS

Gabapentin significantly delayed the onset to heavy drinking, an effect which persisted for 6 weeks after treatment ended. Insomnia improved in both treatment groups during the medication phase, but gabapentin had no differential effects on sleep as measured by either subjective report or polysomnography.

CONCLUSION

Because gabapentin is a short-acting medication that was taken only at nighttime in this study, it may possibly exert a nocturnal effect that prevents relapse to heavy drinking by a physiological mechanism not measured in this pilot study.

Pregabalin in the discontinuation of long-term benzodiazepines' use

OBJECTIVE

Tolerance, dependence, and adverse effects on cognitive functions are well-known consequences of long-term use of benzodiazepines (BDZ), especially at high doses, raising thorny therapeutic problems in their discontinuation. One promising pharmacological agent in BDZ discontinuation might be the newer anti-epileptic pregabalin, already successfully tested in the treatment of anxiety disorders.

METHODS

We report on a sample of 15 patients with long-term, mostly high-dose dependence from BDZ, treated with pregabalin in an open-label study at doses 225-900 mg.

RESULTS

All patients discontinued successfully BDZ in 3-14 weeks, moreover with a significant reduction of their previous anxiety levels under BDZ. In addition, patients showed also a significant amelioration in their cognitive functioning. Pregabalin's side-effects were mild and transient, lasting only during the first 2 weeks of treatment.

CONCLUSION

Although preliminary, our findings suggest that pregabalin may be one new promising agent in the treatment of BDZ dependence.

Pregabalin in the discontinuation of long-term benzodiazepine use: a case-series

Tolerance, dependence, and adverse effects on cognitive functions are well known consequences of long-term use of benzodiazepines (BDZ), especially at high doses; this raises thorny therapeutic problems in their discontinuation. One promising pharmacological agent in BDZ discontinuation might be the newer antiepileptic, pregabalin (PGB), which has already successfully been tested in the treatment of anxiety disorders. We report on a series of four women with long-term, high-dose dependence on BDZ, who were treated with PGB at doses of 225-600 mg. All four patients discontinued BDZ successfully in 3-7 weeks. Moreover, they had an impressive reduction of their previous anxiety levels under BDZ. In addition, the patients showed a clinically significant amelioration in their cognitive functioning. The side effects of PGB were mild and transient, persisting only during the first 2 weeks of treatment. Although our findings are preliminary, they suggest that PGB might be one of the most promising of the newer agents in the treatment of BDZ dependence.

Antiallodynic effect of pregabalin in rat models of sympathetically maintained and sympathetic independent neuropathic pain

Pregabalin binds to the voltage-dependent calcium channel alpha2delta subunit and modulates the release of neurotransmitters, resulting in analgesic effects on neuropathic pain. Neuropathic pain has both sympathetically maintained pain (SMP) and sympathetic independent pain (SIP) components. We studied the antiallodynic effects of pregabalin on tactile allodynia (TA) and cold allodynia (CA) in SMP-and SIP-dominant neuropathic pain models. Allodynia was induced by ligation of the L5 and L6 spinal nerves (SMP model) or by transection of the tibial and sural nerves (SIP model) in rats. For intrathecal drug administration, a PE-10 catheter was implanted through the atlantooccipital membrane to the lumbar enlargement. Pregabalin was administered either intraperitoneally (IP) or intrathecally (IT) and dosed up incrementally until an antiallodynic effect without sedation or motor impairment was apparent. TA was assessed using von Frey filaments, and CA was assessed using acetone drops. IP-administered pregabalin dose-dependently attenuated TA in both models and CA in the SMP model, but not CA in the SIP model. IT-administered pregabalin dose-dependently attenuated both TA and CA in both models. However, the dose response curve of IT-administered pregabalin in SMP was shifted to left from that of SIP and the ED50 of IT-administered pregabalin for CA in SMP was about 900 times less than that in SIP. These findings suggest that pregabalin exerts its antiallodynic effect mainly by acting at the spinal cord, and that IT-administered pregabalin has more potent antiallodynic effects in SMP. The alpha2delta subunit might be less involved in the CA in SIP.

Pregabalin: A novel γ-aminobutyric acid analogue in the treatment of neuropathic pain, partial-onset seizures, and anxiety disorders

BACKGROUND

The US Food and Drug Administration (FDA) approved pregabalin in December 2004 for the treatment of neuropathic pain associated with diabetic peripheral neuropathy and postherpetic neuralgia. Pregabalin is the first drug approved in the United States and in Europe for both conditions. In June 2005, pregabalin was approved as an adjunctive treatment in adults with partial-onset seizures. The FDA currently is considering the approval of pregabalin as adjunctive therapy in adults with generalized anxiety disorder (GAD) or social anxiety disorder (SAD).

OBJECTIVES

The goals of this review were to summarize the pharmacology, pharmacokinetics, efficacy, and tolerability of pregabalin; review its approved uses in the management of neuropathic pain and refractory partial-onset seizures; and investigate its potential use in patients with GAD or SAD.

METHODS

Relevant English-language literature was identified through a search of MEDLINE (1993-June 2006) and International Pharmaceutical Abstracts (2000-June 2006). The search terms included pregabalin, Lyrica, S-(+)-3 isobutyl-gaba, PN, DPN, diabetic peripheral neuropathy, PHN, postherpetic neuralgia, partial seizures, epilepsy, generalized anxiety disorder, and CI-1008.

RESULTS

In 4 clinical trials in a total of 1068 patients with diabetic peripheral neuropathy, the patients receiving pregabalin 300 to 600 mg/d had significantly greater improvement in mean pain scores than placebo recipients (P < or = 0.01). Patients with postherpetic neuralgia receiving pregabalin 450 to 600 mg/d had significantly greater improvement in relief of pain and pain-related sleep interference than placebo recipients (P < or = 0.002). Patients with refractory partial-onset seizures who received pregabalin 150 to 600 mg/d (divided into 2 or 3 doses) concomitantly with antiepileptic drugs had significantly fewer seizures than placebo recipients (P < or = 0.001). In the 3 studies that evaluated the efficacy of pregabalin in patients with GAD or SAD, the patients receiving pregabalin 200 to 600 mg/d (divided into 2 or 3 daily doses) had a significantly greater reduction in mean pain scores on the Hamilton Anxiety Scale than placebo recipients (P < or = 0.01). Across all the reviewed clinical trials, the most commonly reported adverse effects (AEs) were those affecting the central nervous system, including somnolence (< or =50%), dizziness (< or =49%), and headache (< or =29%). AEs resulted in withdrawal from the study in < or =32% of patients.

CONCLUSIONS

Pregabalin appears to be an effective therapy in patients with diabetic peripheral neuropathy, postherpetic neuralgia, and adults with refractory partial-onset seizures. The available data suggest that pregabalin may be beneficial as an adjunctive therapy in adult patients with GAD or SAD.

Synthesis and SAR of novel 2-arylthiazolidinones as selective analgesic N-type calcium channel blockers

A series of new N-type (Ca(v)2.2) calcium channel blockers derived from the 'hit' structures 2-(3-bromo-4-fluorophenyl)-3-(2-pyridin-2-ylethyl)thiazolidin-4-one 9 and its 2-[4-(4-bromophenyl)pyridin-3-yl]-3-isobutyl analogue 10 is described. Extensive SAR studies using a range of synthetic approaches resulted in novel, patented compounds with IC50 values of up to 0.2 microM in an in vitro IMR32 assay, and selectivities for N/L of up to 30-fold. The new compounds described have potential in treatment of neuropathic pain.

Targeting N-type and T-type calcium channels for the treatment of pain

Severe chronic pain afflicts a large number of people worldwide but satisfactory relief from such pain is difficult to achieve with drugs that are currently available, and so there is a great need for the development of new, efficacious and safe analgesics. Voltage-gated calcium-permeable ion channels are multi-subunit complexes that regulate neuronal excitability, action-potential firing patterns and neurotransmission in nociceptive pathways. Although multiple subtypes of voltage-gated calcium channels exist, pharmacological and ion-channel gene knockdown approaches in animals have revealed N-type and T-type calcium channels to be particularly attractive molecular targets for the discovery and development of new analgesic drugs. The recent approval of Prialt (Elan Pharmaceuticals) provides the ultimate target validation for N-type calcium channels, namely proof that they are key regulators of nociceptive signaling in humans.

Pregabalin is effective against behavioral and electrographic seizures during alcohol withdrawal

AIMS

Pregabalin has been shown to possess anticonvulsant, analgesic, and anxiolytic properties in a variety of testing situations. This study was designed to evaluate the ability of pregabalin to exert its anticonvulsant effects against behavioral and electrographic measures of CNS hyperexcitability associated with alcohol withdrawal in a mouse model of ethanol dependence.

METHODS

Adult mice were chronically exposed to ethanol and, upon withdrawal, were tested for behavioral signs of seizure activity (handling-induced convulsions) or abnormalities in spontaneous EEG activity recorded from cortical and subcortical sites.

RESULTS

Pregabalin (50-200 mg/kg) administered 1 and 4 h into withdrawal dose dependently reduced severity of handling-induced convulsions in comparison to vehicle-treated mice. Similarly, pregabalin reduced the frequency in which EEG activity was interrupted by trains of high-voltage synchronous activity in a dose-related fashion. Finally, pregabalin treatment of repeated withdrawals was effective in blocking the development of withdrawal sensitization observed in vehicle-treated mice.

CONCLUSIONS

Collectively, these results suggest that pregabalin may be an effective therapeutic agent for medical management of alcohol detoxification.

Pregabalin: a new neuromodulator with broad therapeutic indications

OBJECTIVE

To review pregabalin's pharmacology, pharmacokinetics, efficacy, and adverse effects in the treatment of neuropathic pain, epilepsy, and anxiety.

DATA SOURCES

A MEDLINE search (1993-October 2005) for peer-reviewed English-language publications was performed. Abstracts from professional meetings were also included. Key terms were anxiety, diabetic neuropathy, epilepsy, neuropathic pain, postherpetic neuralgia, pregabalin, and seizures.

STUDY SELECTION AND DATA EXTRACTION

Basic pharmacology data were extracted from animal studies; pharmacokinetic data were extracted from human studies. Multicenter, double-blind, placebo-controlled, parallel-group studies were included to describe the efficacy and adverse effects of pregabalin.

DATA SYNTHESIS

Pregabalin is a new agent that exerts its pharmacodynamic effect by modulating voltage-gated calcium channels. Pregabalin has a linear pharmacokinetic profile. It is completely absorbed, not bound to plasma proteins, not metabolized, and eliminated unchanged through the kidneys. Doses must be adjusted in patients with renal insufficiency. Clinical trials showed that pregabalin is effective in neuropathic pain associated with postherpetic neuralgia, diabetic peripheral neuropathy, in partial epilepsy as adjunctive therapy, and in generalized and social anxiety disorders. The most common adverse effects were dizziness and somnolence. Few serious adverse effects were reported. Pregabalin should not be discontinued rapidly.

CONCLUSIONS

Pregabalin is an effective and safe analgesic, antiepileptic, and anxiolytic medicine. It will provide a new treatment option for patients with neuropathic pain and partial epilepsy.

Pregabalin for Pain Management

Pregabalin is a new analog of the neurotransmitter gamma-aminobutyric acid (GABA). It is an alpha2-delta (alpha2-delta) ligand that has analgesic, anticonvulsant, and anxiolytic activity. Alpha2-delta is an auxiliary protein associated with voltage-gated calcium channels. Pregabalin binds potently to the alpha2-delta subunit resulting in modulation of calcium channels and reduction in the release of several neurotransmitters, including glutamate, norepinephrine, serotonin, dopamine, and substance P. This review discusses the pharmacology of this medication as well as available studies in patients.