Efficacy and safety of pregabalin in generalised anxiety disorder: A critical review of the literature

Pharmacotherapy and cognitive bias modification for the treatment of anxiety disorders

INTRODUCTION

Anxiety disorders are characterized by widespread and persistent anxiety or recurrent panic attacks. As a result of their high prevalence, chronicity, and comorbidity, patients' quality of life and functioning are severely compromised. However, several patients do not receive treatment.

AREAS COVERED

This review discusses the effectiveness, safety, and limitations of major medications and cognitive bias modification (CBM) for treating anxiety disorders. The possibility of combined treatment is also discussed in the literature. Furthermore, drawing on Chinese cultural perspectives, the authors suggest that anxiety can be recognized, measured, and coped with at three levels of skill (), vision (), and Tao ().

EXPERT OPINION

The combination of pharmacotherapy and CBM is possibly more effective in treating anxiety disorders than either treatment alone. However, clinicians and patients should participate in the joint decision-making process and consider comprehensive factors. Moderate anxiety has adaptive significance. In the coming years, by combining the downward analytical system of western culture with the upward integrative system of Chinese culture, a comprehensive understanding of anxiety and anxiety disorders should be established, rather than focusing only on their treatment.

Edema related to treatment with psychotropic drugs

Edema as an adverse drug reaction is a commonly underestimated yet potentially debilitating condition. This study analyzes the incidence of severe psychotropic drug-induced edema (e.g., edema affecting the face, legs, or multiple body parts and lasting for more than 1 week, or in any case necessitating subsequent diuretic use) among psychiatric inpatients. The cases under examination are derived from an observational pharmacovigilance program conducted in German-speaking countries ("Arzneimittelsicherheit in der Psychiatrie", AMSP) from 1993 to 2016. Among the 462,661 inpatients monitored, severe edema was reported in 231 cases, resulting in an incidence of 0.05%. Edema occurred more frequently in women (80% of all cases) and older patients (mean age 51.8 years). Pregabalin had the highest incidence of severe edema, affecting 1.46‰ of patients treated with pregabalin, followed by mirtazapine (0.8‰). The majority of edema cases showed a positive response to appropriate countermeasures, such as dose reduction and drug discontinuation, and resolved by the end of the observation period. While most instances of drug-induced edema are reversible, they can have a significant impact on patient well-being and potentially result in decreased treatment adherence. It is, therefore, crucial to remain vigilant regarding risk-increasing circumstances during treatment with psychotropic drugs.

The anxiolytic effects of preoperative administration of pregabalin in comparison to diazepam and placebo

We aimed to evaluate the potential anxiolytic effects of premedication with pregabalin, compared with diazepam and placebo. We conducted this non-inferiority, double-blind, randomized controlled trial in ASA classification I-II patients aged 18-70 years, scheduled for elective surgery under general anesthesia. They were allocated to receive pregabalin (75 mg the night before surgery and 150 mg 2 h before surgery), diazepam (5 and 10 mg in the same manner) or placebo. Preoperative anxiety was evaluated using verbal numerical rating scale (VNRS) and Amsterdam Preoperative Anxiety and Information Scale (APAIS) before and after premedication. Sleep quality, sedation level, and adverse effects were assessed as secondary outcomes. A total of 231 patients were screened and 224 completed the trial. The mean change (95%CI) in anxiety scores from before to after medication in pregabalin, diazepam, and placebo groups for VNRS were - 0.87 (- 1.43, - 0.30), - 1.17 (- 1.74, - 0.60), and - 0.99 (- 1.56, - 0.41), and for APAIS were - 0.38 (- 1.04, 0.28), - 0.83 (- 1.49, - 0.16), and - 0.27 (- 0.95, 0.40). The difference in change for pregabalin versus diazepam was 0.30 (- 0.50, 1.11) for VNRS and 0.45 (- 0.49, 1.38) for APAIS, exceeding the limit of inferiority for APAIS of 1.3. Sleep quality was statistically different between pregabalin and placebo groups (p = 0.048). Sedation in pregabalin and diazepam groups were significantly higher than placebo group (p = 0.008). No significant differences of other side effects, except dry mouth was higher in placebo group compared with diazepam (p = 0.006). The study filed to provide evidence at non-inferiority of pregabalin compared to diazepam. Furthermore, premedication with either pregabalin or diazepam did not significantly reduce the preoperative anxiety in comparison to placebo, despite the fact that both resulted in higher levels of sedation. Clinicians should weigh the benefits and risks of premedication with these 2 drugs.Thai Clinical Trials Registry: TCTR20190424001 (24/04/2019) Registry URL: https://www.thaiclinicaltrials.org/ .

Co-prescribing of Central Nervous System-Active Medications for COPD Patients: Impact on Emergency Room Visits and Hospitalization

BACKGROUND

Anxiety and chronic pain are common comorbidities in patients with chronic obstructive pulmonary disease (COPD), which are frequently managed with benzodiazepines (BZDs) and opioids, respectively.

OBJECTIVE

The purpose of this study was to determine whether different combinations of opioids, BZD, and their substitutes-gabapentinoids (GABA) and selective serotonin reuptake inhibitors/serotonin-norepinephrine reuptake inhibitors (SSRIs/SNRIs)-are associated with lower risk of acute respiratory events in COPD patients with co-occurring chronic pain and anxiety.

METHODS

This retrospective cohort study used a nationally representative sample of Medicare beneficiaries with COPD, chronic pain, and anxiety. Patients were grouped based on drug combination (opioid + BZD/Z-hypnotics, opioid + GABA, opioid + SSRI/SNRI, BZD/Z-hypnotics + GABA, BZD/Z-hypnotics + SSRI/SNRI, GABA + SSRI/SNRI, or ≥3 drugs). The primary outcome was emergency room (ER) visit or hospitalization due to acute respiratory events assessed up to 180 days following initiation of drug combination. Overdose secondary to central nervous system (CNS)-related drugs was also assessed up to 180 days following initiation of drug combination.

RESULTS

The drug combination opioid + GABA was associated with decreased risk for ER visit (hazard ratio [HR] = 0.73; 95% CI = 0.61-0.87) and hospitalization (HR = 0.69; 95% CI = 0.55-0.85). Opioid + SSRI/SNRI also showed decreased risk for ER visit (HR = 0.84; 95% CI = 0.71-0.99). There was no significant difference in risk for CNS-related drug overdose among different drug combinations compared with opioid + BZD/Z-hypnotics.

CONCLUSION AND RELEVANCE

Opioids in combination with GABA and SSRI/SNRI demonstrate relatively lower risk for acute respiratory events among patients with COPD and comorbid chronic pain and anxiety. The findings emphasize the need for multimodal management in this vulnerable population.

Optimization of Therapy in Patients with Epilepsy and Psychiatric Comorbidities: Key Points

Psychiatric disorder comorbidity in patients with epilepsy (PWE) is very frequent with a mean percentage prevalence of up to 50% and even higher. Such a high frequency suggests that epilepsy and psychiatric disorders might share common pathological pathways. Various aspects contribute in making the matter very complex from a therapeutic point of view. Some antiseizure medications (ASMs), namely valproic acid, carbamazepine, and lamotrigine, have mood-stabilising effects and are routinely used for the treatment of bipolar disorder in patients who do not have epilepsy. Pregabalin and, to a lesser extent, gabapentin, exerts anxiolytic effects. However, several ASMs, in particular levetiracetam, topiramate, and perampanel, may contribute to psychiatric disorders, including depression, aggressive behaviour, and even psychosis. If these ASMs are prescribed, the patient should be monitored closely. A careful selection should be made also with psychotropic drugs. Although most of these can be safely used at therapeutic doses, bupropion, some tricyclic antidepressants, maprotiline, and clozapine may alter seizure threshold and facilitate epileptic seizures. Interactions between ASMs and psychotropic medication may make it difficult to predict individual response. Pharmacokinetic interactions can be assessed with drug monitoring and are consequently much better documented than pharmacodynamic interactions. Another aspect that needs a careful evaluation is patient adherence to treatment. Prevalence of non-adherence in PWE and psychiatric comorbidities is reported to reach values even higher than 70%. A careful evaluation of all these aspects contributes in optimizing therapy with a positive impact on seizure control, psychiatric wellbeing, and quality of life.

The role of flumazenil in generalised anxiety disorder: a pilot naturalistic open-label study with a focus on treatment resistance

Background

Anxiety disorders are highly prevalent and chronic disorders with treatment resistance to current pharmacotherapies occurring in approximately one in three patients. It has been postulated that flumazenil (FMZ) is efficacious in the management of anxiety disorders via the removal of α₄β2δ gamma-aminobutyric acid A receptors.

Objective

To assess the safety and feasibility of continuous low-dose FMZ infusions for the management of generalised anxiety disorder (GAD) and collect preliminary efficacy data.

Design

Uncontrolled, open-label pilot study.

Method

Participants had a primary diagnosis of generalised anxiety disorder (GAD) and received two consecutive subcutaneous continuous low-dose FMZ infusions. Each infusion contained 16 mg of FMZ and was delivered over 96 ± 19.2 h. The total dose of FMZ delivered was 32 mg over approximately 8 days. Sodium valproate was given to participants at risk of seizure. The primary outcome was the change in stress and anxiety subscale scores on the Depression Anxiety Stress Scale-21 between baseline, day 8, and day 28.

Results

Nine participants with a primary diagnosis of GAD were treated with subcutaneous continuous low-dose FMZ infusions; seven participants met the criteria for treatment resistance. There was a significant decrease in anxiety and stress between baseline and day 8 and baseline and day 28. There was also a significant improvement in subjective sleep quality from baseline to day 28 measured by the Jenkins Sleep Scale. No serious adverse events occurred.

Conclusion

This study presents preliminary results for subcutaneous continuous low-dose FMZ's effectiveness and safety in GAD. The findings suggest that it is a safe, well-tolerated, and feasible treatment option in this group of patients. Future randomised control trials are needed in this field to determine the efficacy of this treatment.

Engineering of reaction specificity, enantioselectivity and catalytic activity of nitrilase for highly efficient synthesis of pregabalin precursor

Simultaneous evolution of multiple enzyme properties remains challenging in protein engineering. A chimeric nitrilase (BaNIT_M0 ) with high activity towards isobutylsuccinonitrile (IBSN) was previously constructed for biosynthesis of pregabalin precursor (S)-3-cyano-5-methylhexanoic acid ((S)-CMHA). However, BaNIT_M0 also catalyzed the hydration of IBSN to produce by-product (S)-3-cyano-5-methylhexanoic amide. In order to obtain industrial nitrilase with vintage performance, we carried out engineering of BaNIT_M0 for simultaneous evolution of reaction specificity, enantioselectivity and catalytic activity. The best variant V82L/M127I/C237S (BaNIT_M2 ) displayed higher enantioselectivity (E=515), increased enzyme activity (5.4-fold) and reduced amide formation (from 15.8% to 1.9 %) compared with BaNIT_M0 . Structure analysis and molecular dynamics simulations indicated that mutation M127I and C237S restricted the movement of E66 in the catalytic triad, resulting in decreased amide formation. Mutation V82L was incorporated to induce the reconstruction of the substrate binding region in the enzyme catalytic pocket, engendering the improvement of stereoselectivity. Enantio- and regio-selective hydrolysis of 150 g/L IBSN using 1.5 g/L E. coli cells harboring BaNIT_M2 as biocatalyst afforded (S)-CMHA with >99.0% ee and 45.9% conversion, which highlighted the robustness of BaNIT_M2 for efficient manufacturing of pregabalin. This article is protected by copyright. All rights reserved.

Clinical management of withdrawal from benzodiazepine anxiolytic and hypnotic medications

Benzodiazepines continue to be prescribed widely in the management of patients with insomnia or anxiety disorders, despite the availability and acceptability of alternative pharmacological and psychological treatments. Many patients will experience adverse effects during treatment and considerable distress when the dosage is reduced and stopped. Management of benzodiazepine withdrawal includes measures to prevent the development of dependence, careful attention to underlying medical conditions, medication consolidation and gradual dosage reduction, accompanying psychological interventions, occasional prescription of concomitant medication, and relapse prevention with on-going support to address psychosocial stressors. There are needs for easier patient access to services with refined expertise and for further research to optimise strategies for preventing dependence and facilitating withdrawal.

A single injection of pregabalin induces short- and long-term beneficial effects on fear memory and anxiety-like behavior in rats with experimental type-1 diabetes mellitus

Anxiety Disorders and Posttraumatic Stress Disorders (PTSD) associated with type-1 diabetes mellitus (T1DM) are increasingly common comorbidities and the treatment is quite challenging. In that sense, evidence indicates that the anticonvulsant pregabalin is highly effective in treating severe cases of anxiety, as well as PTSD and diabetic neuropathic pain which is also very prevalent in T1DM. Herein, the short- and long-term effects of a single injection of pregabalin on the acquisition of a fear extinction memory and parameters of anxiety in induced-T1DM animals were investigated. For that, we used the contextual fear conditioning (CFC) and elevated plus maze paradigms, respectively. A putative antioxidant activity was also evaluated. Our findings demonstrated that induced-T1DM animals presented greater expression of fear memory, difficulty in extinguishing this fear memory, associated with a more pronounced anxiety-like response. Pregabalin was able to induce a short and long-lasting effect by facilitating the acquisition of the fear extinction memory and inducing a later anxiolytic-like effect. Also, the increased lipid peroxidation levels in the hippocampus and prefrontal cortex of induced-T1DM rats were reduced after pregabalin injection, while the decreased levels of reduced glutathione were increased in the hippocampus. Despite the need for more studies to understand the mechanism of action of pregabalin under these conditions, our data demonstrate for the first time that a single injection of pregabalin in a specific time window was able to improve behavioral parameters in addition to inducing neuroprotective effect. Thus, pregabalin has potential worth exploring for the treatment of PTSD and/or Anxiety associated with T1DM.

Sleep and anxiety: From mechanisms to interventions

Anxiety is the most common mental health problem worldwide. Epidemiological studies show that sleep disturbances, particularly insomnia, affect ∼50% of individuals with anxiety, and that insufficient sleep can instigate or further exacerbate it. This review outlines brain mechanisms underlying sleep and anxiety, by addressing recent human functional/structural imaging studies on brain networks underlying the anxiogenic impact of sleep loss, and the beneficial effect of sleep on these brain networks. We discuss recent developments from human molecular imaging studies that highlight the role of specific brain neurotransmitter mechanisms, such as the adenosinergic receptor system, on anxiety, arousal, and sleep. This review further discusses frontline sleep interventions aimed at enhancing sleep in individuals experiencing anxiety, such as nonbenzodiazepines/antidepressants, lifestyle and sleep interventions and cognitive behavioral therapy for insomnia. Notwithstanding therapeutic success, up to ∼30% of individuals with anxiety can be nonresponsive to frontline treatments. Thus, we address novel non-invasive brain stimulation techniques that can enhance electroencephalographic slow waves, and might help alleviate sleep and anxiety symptoms. Collectively, these findings contribute to an emerging biological framework that elucidates the interrelationship between sleep and anxiety, and highlight the prospect of slow wave sleep as a potential therapeutic target for reducing anxiety.

Prenatal Pregabalin Exposure Alters Postnatal Pain Sensitivity and Some Behavioral Responses in Adult Offspring Rats

BACKGROUND

Prenatal antiepileptic drug exposure could demonstrate both congenital malformations and behavioral impairments in offspring.

OBJECTIVE

This study was performed to assess the effects of prenatal exposure to pregabalin (PGB) on pain response, anxiety, motor activity and some behavior of adult offspring rats.

METHODS

Pregnant Wistar rats received PGB (7.5, 15 and 30 mg/kg/ip) during embryonic days 9.5- 15.5. The pain response, anxiety-like behaviors, locomotor activity, motor balance and coordination and anhedonia of adult offspring were examined by tail-flick and hot plate test, open field test, elevated plus maze (EPM), beam balance test and sucrose preference test in their 60th day of life, respectively.

RESULTS

Prenatal exposure to PGB revealed significant dose-dependent reduction in pain sensitivity (increase in pain latency response) in the hot plate test, especially in females, while anxiety-like behavior assessed in EPM and open field significantly reduced in males. In the open field, locomotor activity reduced significantly after exposure to PGB 30 mg/kg and motor coordination decreased dose-dependently, especially in males. Anhedonia, as an indication of sucrose preference or pleasure response, was not changed.

CONCLUSION

These findings suggest that prenatal PGB exposure could be associated with significant changes in pain response, anxiety, locomotor activity and coordination in adult offspring rats.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pregabalin as a Treatment for Anxiety in Patients With Dementia With Lewy Bodies: A Case Series

BACKGROUND

Anxiety is a common and invalidating symptom of dementia with Lewy bodies (DLB).

METHODS

To evaluate the efficacy of pregabalin as a treatment for anxiety in DLB, we screened all medical files of our patients with DLB for the use of pregabalin in this context.

FINDINGS

Overall, pregabalin was well tolerated. Ten (62.5%) of 16 patients showed an improvement of anxiety, whereas in 3 of them, anxiety disappeared completely, at respectively 3, 11, and 22 months of follow-up, with total daily doses ranging from 75 to 150 mg. Positive response to pregabalin was associated with a significant reduction in benzodiazepine use.

CONCLUSIONS

Pregabalin seems a useful and safe tool for treating anxiety in patients with DLB.

Management of treatment-resistant generalized anxiety disorder

Generalized anxiety disorder (GAD) is characterized by persistent and excessive worry. Around half of the patients treated for GAD will fail to respond to initial treatment. Treatment-resistant (or refractory) GAD is defined as failure to respond to at least 1 trial of antidepressant therapy at adequate dose and duration. Review of the literature indicates several potential medication classes and individual agents that can be used as augmentation strategies to treat residual symptoms when recommended therapy per clinical practice guidelines fails. A thorough literature search revealed 2 medication classes with the largest amount of data to support their use in treatment-resistant GAD treatment: gamma-aminobutyric acid–related agents and atypical antipsychotics. This article focuses on evidence-based recommendations for the use of these agents as adjunctive therapies for patients with treatment-resistant GAD. Different pharmacologic approaches to use these agents are demonstrated through 2 patient cases in which patients have failed first-line treatment options.

Synthesis, anticonvulsant, and antinociceptive activity of new 3-(3-methyl-2,5-dioxo-3-phenylpyrrolidin-1-yl)propanamides and 3-phenyl-butanamides

A focused library of new 3-(3-methyl-2,5-dioxo-3-phenylpyrrolidin-1-yl)propanamides and their nonimide analogs were synthesized and tested for anticonvulsant activity. These compounds were obtained through the coupling reaction of the starting carboxylic acids with appropriate amines. The initial anticonvulsant screening was performed in mice (intraperitoneal administration) using the maximal electroshock seizure (MES) and the subcutaneous pentylenetetrazole (scPTZ) seizure models. The most promising compound 6 showed more potent protection in the MES and scPTZ tests than valproic acid, which is still recognized as one of the most relevant first-line anticonvulsants. The structure-activity relationship analysis revealed that the presence of the pyrrolidine-2,5-dione ring is important but not indispensable to retain anticonvulsant activity. Additionally, compound 6 showed potent antinociceptive properties in the oxaliplatin-induced neuropathic pain model in mice. The most plausible mechanism of action for compound 6 may result from its influence on the neuronal sodium channel (Site 2) and the high-voltage-activated L-type calcium channel.

Consensus statements on the clinical uses of pregabalin for Hong Kong

To facilitate the understanding of pregabalin and optimize its clinical usage in Hong Kong, an expert panel (11 psychiatrists, one family physician and one anesthesiologist) experienced in treating anxiety and somatic symptoms was invited to establish a set of consensus statements based on several discussion areas. A non-systematic literature search for relevant articles was conducted. The panelists addressed the discussion areas by sharing their clinical experience and available literature in a couple of meetings. At the last meeting, consensus statements derived from the proceedings were discussed and finalized. A total of 11 statements were ultimately accepted by panel voting based on their practicability of recommendation in Hong Kong. These statements are aimed to act as a practical reference for local clinicians when they consider prescribing pregabalin in different clinical situations.

Convergence of psychiatric symptoms and restless legs syndrome: A cross-sectional study in an elderly French population

OBJECTIVE

The objective was to evaluate the association between restless legs syndrome (RLS) with generalized anxiety disorder (GAD), major depression disorder (MDD), dysthymia, and GAD-depression comorbidity. Secondary aims were to examine the association between RLS with the cognitive-affective and somatic-vegetative disturbances experienced as part of depression and GAD.

METHODS

This was a cross-sectional study of 1493 elderly participants (median age 80.6 years, 64% women) from Dijon, France. Probable RLS was assessed using the minimal diagnostic criteria of the International Restless Legs Study Group and RLS symptom frequency and treatment. Participants underwent structured interviews for MDD, dysthymia, and GAD. Participants also completed the Center for Epidemiological Studies-Depression scale (CES-D). The association between RLS and psychiatric disorders, their criterion symptoms, or symptom factors was examined using logistic regression.

RESULTS

The point prevalence of probable RLS in this sample was 8.2%. Probable RLS was associated with isolated GAD (odds ratio [OR] 2.17, 95% confidence interval [CI] 1.01-4.68) and comorbid GAD-any depression disorder (OR 3.26, 95% CI 1.14-9.29), but not MDD or dysthymia. Probable RLS was also associated with the GAD criterion worry most days and feeling tense, and the CES-D factors representing depressed affect, somatic symptoms, and positive affect.

CONCLUSIONS

Probable RLS was associated with GAD-depression comorbidity as well as isolated GAD. The findings challenge previous reports linking RLS solely with MDD, suggesting the association is partly driven by GAD-depression comorbidity.

Glutamate Systems in DSM-5 Anxiety Disorders: Their Role and a Review of Glutamate and GABA Psychopharmacology

Serotonin reuptake inhibitors and benzodiazepines are evidence-based pharmacological treatments for Anxiety Disorders targeting serotonin and GABAergic systems, respectively. Although clearly effective, these medications fail to improve anxiety symptoms in a significant proportion of patients. New insights into the glutamate system have directed attention toward drugs that modulate glutamate as potential alternative treatments for anxiety disorders. Here we summarize the current understanding of the potential role of glutamate neurotransmission in anxiety disorders and highlight specific glutamate receptors that are potential targets for novel anxiety disorder treatments. We also review clinical trials of medications targeting the glutamate system in DSM-5 anxiety disorders. Understanding the role of the glutamate system in the pathophysiology of anxiety disorder may aid in developing novel pharmacological agents that are effective in treating anxiety disorders.

Novel pharmacological targets in drug development for the treatment of anxiety and anxiety-related disorders

Current medication for anxiety disorders is suboptimal in terms of efficiency and tolerability, highlighting the need for improved drug treatments. In this review an overview of drugs being studied in different phases of clinical trials for their potential in the treatment of fear-, anxiety- and trauma-related disorders is presented. One strategy followed in drug development is refining and improving compounds interacting with existing anxiolytic drug targets, such as serotonergic and prototypical GABAergic benzodiazepines. A more innovative approach involves the search for compounds with novel mechanisms of anxiolytic action using the growing knowledge base concerning the relevant neurocircuitries and neurobiological mechanisms underlying pathological fear and anxiety. The target systems evaluated in clinical trials include glutamate, endocannabinoid and neuropeptide systems, as well as ion channels and targets derived from phytochemicals. Examples of promising novel candidates currently in clinical development for generalised anxiety disorder, social anxiety disorder, panic disorder, obsessive compulsive disorder or post-traumatic stress disorder include ketamine, riluzole, xenon with one common pharmacological action of modulation of glutamatergic neurotransmission, as well as the neurosteroid aloradine. Finally, compounds such as D-cycloserine, MDMA, L-DOPA and cannabinoids have shown efficacy in enhancing fear-extinction learning in humans. They are thus investigated in clinical trials as an augmentative strategy for speeding up and enhancing the long-term effectiveness of exposure-based psychotherapy, which could render chronic anxiolytic drug treatment dispensable for many patients. These efforts are indicative of a rekindled interest and renewed optimism in the anxiety drug discovery field, after decades of relative stagnation.

Use and safety of antiepileptic drugs in psychiatric inpatients-data from the AMSP study

The psychiatric utilization patterns and risks of antiepileptic drugs (AEDs) were assessed by using data from the drug safety programme Arzneimittelsicherheit in der Psychiatrie over the time period 1993-2013. In a total of 432,215 patients, the main indications for AED use were acute mania, schizoaffective disorder, and schizophrenic and organic psychoses. Valproic acid (VPA) was the most common substance across all of those groups, reaching administration rates of up to 50% since 2005, at which time carbamazepine (CBZ) administration consistently dropped below a rate of 10%. Lamotrigine (LTG) and pregabalin (PGB) increased in relevance after 2005 and 2010, respectively (with administration rates of up to 9%), whereas oxcarbazepine (OXC) was least prevalent (<3%). The mean rates of severe adverse drug reactions (ADRs) ranged from 6 cases per 1000 patients treated (VPA) to 19/1000 (OXC) and were significantly lower with treatment with VPA compared to OXC and CBZ. Hyponatremia was the leading ADR during treatment with OXC; severe allergic skin reactions were most often observed during treatment with CBZ and LTG, and severe oedema was most common during treatment with PGB. Severe hyponatremia induced by OXC was observed significantly more often in female patients than in male patients.

Pregbalin induced recurrent syncopal attacks with prolong QT interval

Long QT syndrome may lead to fatal dysrhythmia. Prolongation of QT interval due to pregabalin has been shown in rats and no data is available in humans. We report a 80-year-old female patient using pregabalin. She was presented to emergency room with syncope attacks. Her admission electrocardiography demonstrated prolonged QT interval. After excluding the possible causes of the long QT syndrome, we attributed prolonged QT interval to pregabalin therapy. After discontinuation of pregabalin QT interval returned to normal range and patient experienced no further syncope attacks. It is first time for documentation of prolonged QT due to pregabalin in humans.

Pregabalin for the treatment of neuropathic pain: a narrative review for primary care providers

BACKGROUND

Neuropathic pain (NeP) is a distinct type of pain caused by damage to the nervous system itself. This often severe and chronic type of pain requires specific treatments that target the underlying pain pathophysiology.

AIM

The purpose of the current narrative review is to provide an overview of pregabalin (Lyrica ¹ ) for the treatment of NeP including its effects on pain, pain-related sleep interference, and other health-related outcomes, timing of therapeutic effect, safety and tolerability, and dosing. The information provided here will help primary care providers develop more effective NeP treatment strategies.

Is pregabalin effective and safe in total knee arthroplasty? A PRISMA-compliant meta-analysis of randomized-controlled trials

BACKGROUND

Pain management after total knee arthroplasty (TKA) varies and has been investigated for years. Pregabalin as an anticonvulsant agent that selectively affects the nociceptive process has been used for pain relief after operation. This meta-analysis was conducted to examine the evidence of pregabalin in TKA.

METHODS

Systematic searches of all related literatures were conducted using the following databases: MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials. Only randomized-controlled trials (RCTs) for TKA were included. The postoperative narcotic requirements, visual analog scale scores, knee flexion range, and relative risk of incidence rate of adverse effects in the pregabalin group versus placebo group were extracted throughout the study.

RESULTS

Seven placebo-controlled RCTs met the inclusion criteria. The use of pregabalin significantly decrease the postoperative total morphine consumption (P < .05) and increase the passive knee flexion range (P < .05). Compared with the control group, the incidence of some side effects (nausea, vomiting, pruritus, and constipation) was less in the pregabalin group (P < .05).

CONCLUSIONS

The administration of pregabalin is not only efficacious in the reduction of narcotic requirements and incidence of some adverse effect, but also workable for the improvement of passive knee flexion range after TKA.

Pharmacotherapy in Generalized Anxiety Disorder: Novel Experimental Medicine Models and Emerging Drug Targets

Many pharmacological and psychological approaches have been found efficacious in patients with generalized anxiety disorder (GAD), but many treatment-seeking patients will not respond and others will relapse despite continuing with interventions that initially had beneficial effects. Other patients will respond but then stop treatment early because of untoward effects such as sexual dysfunction, drowsiness, and weight gain. There is much scope for the development of novel approaches that could have greater overall effectiveness or acceptability than currently available interventions or that have particular effectiveness in specific clinical subgroups. 'Experimental medicine' studies in healthy volunteers model disease states and represent a proof-of-concept approach for the development of novel therapeutic interventions: they determine whether to proceed to pivotal efficacy studies and so can reduce delays in translating innovations into clinical practice. Investigations in healthy volunteers challenged with the inhalation of air 'enriched' with 7.5% carbon dioxide (CO₂) indicate this technique provides a validated and robust experimental medicine model, mirroring the subjective, autonomic, and cognitive features of GAD. The anxiety response during CO₂ challenge probably involves both central noradrenergic neurotransmission and effects on acid-base sensitive receptors and so may stimulate development of novel agents targeted at central chemosensors. Increasing awareness of the potential role of altered cytokine balance in anxiety and the interplay of cytokines with monoaminergic mechanisms may also encourage the investigation of novel agents with modulating effects on immunological profiles. Although seemingly disparate, these two approaches to treatment development may pivot on a shared mechanism in exerting anxiolytic-like effects through pharmacological effects on acid-sensing ion channels.

Effect of pregabalin on fear-based conditioned avoidance learning and spatial learning in a mouse model of scopolamine-induced amnesia

OBJECTIVES

Cognitive deficits are one of the frequent symptoms accompanying epilepsy or its treatment.

METHODS

In this study, the effect on cognition of intraperitoneally administered antiepileptic drug, pregabalin (10 mg/kg), was investigated in scopolamine-induced memory-impaired mice in the passive avoidance task and Morris water maze task. The effect of scopolamine and pregabalin on animals' locomotor activity was also studied.

RESULTS

In the retention phase of the passive avoidance task, pregabalin reversed memory deficits induced by scopolamine (p < 0.05). During the acquisition phase of the Morris water maze pregabalin-treated memory-impaired mice performed the test with longer escape latencies than the vehicle-treated mice (significant at p < 0.05 on Day 5, and at p < 0.001 on Day 6). There were no differences in this parameter between the scopolamine-treated control group and pregabalin-treated memory-impaired mice, which indicated that pregabalin had no influence on spatial learning in this task. During the probe trial a significant difference (p < 0.05) was observed in terms of the mean number of target crossings between vehicle-treated mice and pregabalin-treated memory-impaired mice but there was no difference between the scopolamine-treated control group and mice treated with pregabalin + scopolamine. Pregabalin did not influence locomotor activity increased by scopolamine.

DISCUSSION

In passive avoidance task, pregabalin reversed learning deficits induced by scopolamine. In the Morris water maze, pregabalin did not influence spatial learning deficits induced by scopolamine. These results are relevant for epileptic patients treated with pregabalin and those who use it for other therapeutic indications (anxiety, pain).

Early improvement with pregabalin predicts endpoint response in patients with generalized anxiety disorder: an integrated and predictive data analysis

Generalized anxiety disorder (GAD), a common mental disorder, has several treatment options including pregabalin. Not all patients respond to treatment; quickly determining which patients will respond is an important treatment goal. Patient-level data were pooled from nine phase II and III randomized, double-blind, short-term, placebo-controlled trials of pregabalin for the treatment of GAD. Efficacy outcomes included the change from baseline in the Hamilton Anxiety Scale (HAM-A) total score and psychic and somatic subscales. Predictive modelling assessed baseline characteristics and early clinical responses to determine those predictive of clinical improvement at endpoint. A total of 2155 patients were included in the analysis (1447 pregabalin, 708 placebo). Pregabalin significantly improved the HAM-A total score compared with the placebo at endpoint, treatment difference (95% confidence interval), -2.61 (-3.21 to -2.01), P<0.0001. Pregabalin significantly improved HAM-A psychic and somatic scores compared with placebo, -1.52 (-1.85 to -1.18), P<0.0001, and -1.10 (-1.41 to -0.80), P<0.0001, respectively. Response to pregabalin in the first 1-2 weeks (≥20 or ≥30% improvement in HAM-A total, psychic or somatic score) was predictive of an endpoint greater than or equal to 50% improvement in the HAM-A total score. Pregabalin is an effective treatment option for patients with GAD. Patients with early response to pregabalin are more likely to respond significantly at endpoint.

Anxiety

Anxiety disorders (separation anxiety disorder, selective mutism, specific phobias, social anxiety disorder, panic disorder, agoraphobia, and generalised anxiety disorder) are common and disabling conditions that mostly begin during childhood, adolescence, and early adulthood. They differ from developmentally normative or stress-induced transient anxiety by being marked (ie, out of proportion to the actual threat present) and persistent, and by impairing daily functioning. Most anxiety disorders affect almost twice as many women as men. They often co-occur with major depression, alcohol and other substance-use disorders, and personality disorders. Differential diagnosis from physical conditions-including thyroid, cardiac, and respiratory disorders, and substance intoxication and withdrawal-is imperative. If untreated, anxiety disorders tend to recur chronically. Psychological treatments, particularly cognitive behavioural therapy, and pharmacological treatments, particularly selective serotonin-reuptake inhibitors and serotonin-noradrenaline-reuptake inhibitors, are effective, and their combination could be more effective than is treatment with either individually. More research is needed to increase access to and to develop personalised treatments.

Alpha2delta ligands, gabapentin, pregabalin and mirogabalin: a review of their clinical pharmacology and therapeutic use

INTRODUCTION

The first two alpha₂delta ligands - gabapentin (GBP) and pregabalin (PGB) - were initially synthesized as antiepileptics; however, they were later also found to be useful for the treatment of additional conditions. Areas covered: Relevant publications describing potential underlying mechanisms, clinical pharmacokinetics/pharmacokinetics, and clinical efficacy and safety of these drugs in various disease conditions were searched in PubMed and Scopus and included in this review. Expert commentary: GBP and PGB are effective for the treatment neuropathic pain, fibromyalgia and epilepsy; in addition, they may be useful for the reduction of postoperative pain. PGB is also effective for the treatment of generalized anxiety disorder and GBP for the treatment of restless legs syndrome. GBP may be considered a treatment option for pain associated with Guillain-Barré Syndrome and phantom limb and for the management of uremic pruritus. Mirogabalin (MGB), recently developed, is being investigated for the treatment of peripheral neuropathic pain and fibromyalgia, showing promising results in patients with diabetic peripheral neuropathy. Their most frequent adverse reactions are of neuropsychiatric nature and include fatigue, dizziness, sedation, somnolence, and ataxia; peripheral edema and weight gain are also frequently described. Pharmacokinetic interactions are scarce; however, pharmacodynamic interactions have been described in association with drugs with CNS-depressant effects.