The Positive Allosteric Modulator of α2/3-Containing GABAA Receptors, KRM-II-81, Is Active in Pharmaco-Resistant Models of Epilepsy and Reduces Hyperexcitability after Traumatic Brain Injury.

The imidizodiazepine, 5-(8-ethynyl-6-(pyridin-2-yl)-4H-benzo[f]imidazo[1,5-a][1,4]diazepin-3-yl)oxazole (KRM-II-81), is selective for α2/3-containing GABAA receptors. KRM-II-81 dampens seizure activity in rodent models with enhanced efficacy and reduced motor-impairment compared with diazepam. In the present study, KRM-II-81 was studied in assays designed to detect antiepileptics with improved chances of impacting pharmaco-resistant epilepsies. The potential for reducing neural hyperactivity weeks after traumatic brain injury was also studied. KRM-II-81 suppressed convulsions in corneal-kindled mice. Mice with kainate-induced mesial temporal lobe seizures exhibited spontaneous recurrent hippocampal paroxysmal discharges that were significantly reduced by KRM-II-81 (15 mg/kg, orally). KRM-II-81 also decreased convulsions in rats undergoing amygdala kindling in the presence of lamotrigine (lamotrigine-insensitive model) (ED50 = 19 mg/kg, i.p.). KRM-II-81 reduced focal and generalized seizures in a kainate-induced chronic epilepsy model in rats (20 mg/kg, i.p., three times per day). In mice with damage to the left cerebral cortex by controlled-cortical impact, enduring neuronal hyperactivity was dampened by KRM-II-81 (10 mg/kg, i.p.) as observed through in vivo two-photon imaging of layer II/III pyramidal neurons in GCaMP6-expressing transgenic mice. No notable side effects emerged up to doses of 300 mg/kg KRM-II-81. Molecular modeling studies were conducted: docking in the binding site of the α1ß3γ2L GABAA receptor showed that replacing the C8 chlorine atom of alprazolam with the acetylene of KRM-II-81 led to loss of the key interaction with α1His102, providing a structural rationale for its low affinity for α1-containing GABAA receptors compared with benzodiazepines such as alprazolam. Overall, these findings predict that KRM-II-81 has improved therapeutic potential for epilepsy and post-traumatic epilepsy. SIGNIFICANCE STATEMENT: We describe the effects of a relatively new orally bioavailable small molecule in rodent models of pharmaco-resistant epilepsy and traumatic brain injury. KRM-II-81 is more potent and generally more efficacious than standard-of-care antiepileptics. In silico docking experiments begin to describe the structural basis for the relative lack of motor impairment induced by KRM-II-81. KRM-II-81 has unique structural and anticonvulsant effects, predicting its potential as an improved antiepileptic drug and novel therapy for post-traumatic epilepsy.

Sodium Divalproate in Low Alternating Daily Doses for Migraine Prevention: A Retrospective Study.

BACKGROUND AND OBJECTIVE: Sodium divalproate is an effective neuromodulator for migraine prevention. Recommended doses vary from 1,000 to 1,500 mg/day, which may provoke unpleasant side effects as weight gain, tremor, and hair loss. Some patients do respond to lower doses even used once daily in ER presentations, but alternating low daily doses was never studied so far. The aim of this study was to evaluate the adherence, the tolerability, and the efficacy of sodium divalproate (SD) in low alternating daily doses for migraine prevention in patients of a tertiary center. METHODS: Consecutive migraineurs from a tertiary center to whom SD was prescribed as monotherapy from January 2017 until September 2018 were studied retrospectively. The doses were 250 mg alternated with 500 mg and were used based on the treating physician expertise and previous experience with tolerability issues when using higher doses. Headache frequency compared to baseline, adherence expressed by returning to a visit after 2 and 4 months and side effects reported by the patients, were evaluated. RESULTS: Sixty-eight patients (53 women and 15 men, aged 18-58) were included. The average headache frequency (HF) during baseline was decreased from 8.2 to 5.1 headache days/month among the 50 out of 68 patients returning at 2 months (adherence rate 73.5%). Weight gain was reported by 15 patients (30%, mean 2.1 kg). At 4 months, HF was reduced to 4.2 days/month (adherence rate 61.8%, n = 42) and weight gain reported by 18 patients (42.8%, mean 2.3 kg). CONCLUSIONS: Despite the retrospective open design, which cannot allow definitive conclusions, SD in low alternating daily doses seems to be effective as with higher doses, but still induce modest weight gain. Controlled studies are necessary to confirm these observations.

Distinguishing features between valproate-induced tremor and essential tremor.

BACKGROUND: Tremor frequently occurs in patients taking valproate and may resemble that observed in patients with essential tremor (ET). We aimed to compare the distribution, severity, and functional impact of both types of tremor. METHODS: Among 118 consecutive individuals taking valproate, we identified 28 patients with valproate-induced tremor severe enough to require pharmacological treatment; through evaluations using the Clinical Rating Scale for Tremor (CRST), they were compared with 29 consecutive patients with ET. RESULTS: Patients with valproate-induced tremor were significantly younger than those with ET: 35.6 ± 15.4 vs 58.8 ± 20.5 years (P < .001), with a shorter evolution time of tremor (P < .001). Total CRST scores did not differ between groups (P = .164), neither in subscores of Parts A (P = .321), B (P = .094), and C (P = .386). Patients with valproate-induced tremor had a higher proportion of postural tongue tremor compared with ET patients: 22 (79%) vs 15 (52%) (P = .034). A frank tremor axis in the Archimedes spirals was observed in a higher proportion of patients with ET compared to valproate-induced tremor: 31% vs 3.6% (P = .006). CONCLUSIONS: Patients with valproate-induced tremor requiring pharmacological treatment have similar distribution, CRST scores, and functional impact than those with ET.

Risk of cardiac events in Long QT syndrome patients when taking antiseizure medications.

Many antiseizure medications (ASMs) affect ion channel function. We investigated whether ASMs alter the risk of cardiac events in patients with corrected QT (QTc) prolongation. The study included people from the Rochester-based Long QT syndrome (LQTS) Registry with baseline QTc prolongation and history of ASM therapy (n = 296). Using multivariate Anderson-Gill models, we assessed the risk of recurrent cardiac events associated with ASM therapy. We stratified by LQTS genotype and predominant mechanism of ASM action (Na+ channel blocker and gamma-aminobutyric acid modifier.) There was an increased risk of cardiac events when participants with QTc prolongation were taking vs off ASMs (HR 1.65, 95% confidence interval [CI] 1.36-2.00, P < 0.001). There was an increased risk of cardiac events when LQTS2 (HR 1.49, 95% CI 1.03-2.15, P = 0.036) but not LQTS1 participants were taking ASMs (interaction, P = 0.016). Na+ channel blocker ASMs were associated with an increased risk of cardiac events in participants with QTc prolongation, specifically LQTS2, but decreased risk in LQTS1. The increased risk when taking all ASMs and Na+ channel blocker ASMs was attenuated by concurrent beta-adrenergic blocker therapy (interaction, P < 0.001). Gamma-aminobutyric acid modifier ASMs were associated with an increased risk of events in patients not concurrently treated with beta-adrenergic blockers. Female participants were at an increased risk of cardiac events while taking all ASMs and each class of ASMs. Despite no change in overall QTc duration, pharmacogenomic analyses set the stage for future prospective clinical and mechanistic studies to validate that ASMs with predominantly Na+ channel blocking actions are deleterious in LQTS2, but protective in LQTS1.

Clinical trial of L-Carnitine and valproic acid in spinal muscular atrophy type I.

INTRODUCTION: The aim of this study was to determine the safety and therapeutic potential of L-carnitine and valproic acid (VPA) in infants with spinal muscular atrophy (SMA). METHODS: Our investigation was an open-label phase 2 multicenter trial of L-carnitine and VPA in infants with SMA type I with retrospective comparison to an untreated, matched cohort. Primary outcomes were: safety and adverse events; secondary outcomes were survival, time to death/>16 hours/day of ventilator support; motor outcomes; and maximum ulnar compound motor action potential amplitude. RESULTS: A total of 245 AEs were observed in 35 of the 37 treated subjects (95%). Respiratory events accounted for 49% of all adverse events, resulting in 14 deaths. Survival was not significantly different between treated and untreated cohorts. DISCUSSION: This trial provides evidence that, in infants with SMA type I, L-carnitine/VPA is ineffective at altering survival. The substantial proportion of infants reaching end-points within 6 months of enrollment underscores the urgent need for pre-symptomatic treatment in SMA type I. Muscle Nerve 57: 193-199, 2018.

[Pharmacological treatment of chronic non-cancer pain].

19% of the grown-up Danish population suffer from a chronic pain condition. Most patients are treated by general practi-tioners (GPs), and only a smaller group need specialist treatment. This article goes through the pharmacological possibilities available with a special focus on treatment by GPs. For chronic pain as fibromyalgia and low back pain non-steroidal anti-inflammatory drugs and paracetamol are not recommended on a regular basis. The main pharmacological treatment is tricyclic antidepressants and gabapentinoids. If opioids are needed, long acting drugs are preferred.

The Association between GABA-Modulators and Clostridium difficile Infection - A Matched Retrospective Case-Control Study.

OBJECTIVE: Recently, metabolomics studies have suggested that the neurotransmitter γ-amino butyric acid (GABA) may modulate C. difficile infection (CDI) pathogenesis. In the present study, we investigated the association between GABA-modulating pharmaceuticals and CDI development. METHODS: In July-December 2013, we performed a matched, retrospective case-control study in Skåne county, Sweden, to assess the association between the use of GABA-modulators (defined as regular use of at least one of the following: zolpidem, zopiclone, benzodiazepines, gabapentin, pregabalin or baclofen) and CDI. Multivariate regression models, adjusted for known risk factors for CDI, were fitted to assess the associations and a propensity score-adjusted analysis was performed. RESULTS: The study included 292 cases and 292 matched controls. In a multivariate regression model only recent antibiotic use (clindamycin, cephalosporins and fluoroquinolones) and nursing home residency was significantly associated with CDI. The regular use of any GABA-modulator was not associated with CDI (OR = 1.07, 95%CI 0.69-1.66, p = 0.76). The association between regular use of the selective GABA-agonist zolpidem and CDI trended towards significance (OR = 2.31, 95%CI 0.91-5.86, p = 0.078). These associations remained when only cases treated with antibiotics were included. Corresponding findings for zolpidem was observed in a propensity-score adjusted analysis (OR = 2.52, 95% CI 0.91-6.97, p = 0.075). Severe initial CDI was significantly associated with CDI recurrence (OR = 3.77, 95% CU 1.20-11.86, p = 0.023). CONCLUSION: This study did not identify a general association between GABA-modulators and CDI. A trend towards a significant association between zolpidem and CDI was observed, an association that should be re-assessed in a study appropriately powered for this particular hypothesis.

Gamma aminobutyric acid (GABA) modulators for amyotrophic lateral sclerosis/motor neuron disease.

BACKGROUND: Imbalance of gamma aminobutyric acid (GABA) and related modulators has been implicated as an important factor in the pathogenesis of amyotrophic lateral sclerosis (ALS), which is also known as motor neuron disease (MND). In this context, the role and mechanism of action of gabapentin and baclofen have been extensively investigated, although with conflicting results. This is the first systematic review to assess clinical trials of GABA modulators for the treatment of ALS. OBJECTIVES: To examine the efficacy of gabapentin, baclofen, or other GABA modulators in delaying the progression of ALS, and to evaluate adverse effects of these interventions SEARCH METHODS: On 16 August 2016, we searched the Cochrane Neuromuscular Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL Plus, AMED, and LILACS. In addition, we checked the bibliographies of the trials found in order to identify any other trials, and contacted trial authors to identify relevant unpublished results or additional clinical trials. On 30 August 2016, we searched two clinical trials registries. SELECTION CRITERIA: Types of studies: double-blind randomized controlled trials (RCTs) or quasi-RCTsTypes of participants: adults with a diagnosis of probable or definite ALSTypes of interventions: gabapentin, baclofen, or other GABA modulators compared with placebo, no treatment, or each otherPrimary outcome: survival at one year from study enrollmentSecondary outcomes: individual rate of decline of maximum voluntary isometric contraction (MVIC), expressed as arm megascore; rate of decline of per cent predicted forced vital capacity (FVC); rate of decline of ALS Functional Rating Scale (ALSFRS); health-related quality of life; survival evaluated by pooling hazards; and adverse events DATA COLLECTION AND ANALYSIS: At least two review authors independently checked titles and abstracts identified by the searches. The review authors obtained and independently analyzed original individual participant data from each included study; additional review authors and the Cochrane Neuromuscular Managing Editor checked the outcome data. Two authors independently assessed the risk of bias in included studies. Data collection and analysis: At least two review authors independently checked titles and abstracts identified by the searches. The review authors obtained and independently analyzed original individual participant data from each included study; additional review authors and the Cochrane Neuromuscular Managing Editor checked the outcome data. Two authors independently assessed the risk of bias in included studies. MAIN RESULTS: We identified two double-blind RCTs of gabapentin treatment in ALS for inclusion in this review. We found no eligible RCTs of baclofen or other GABA modulators. The selected studies were phase II and phase III trials, which lasted six and nine months, respectively. They were highly comparable because both were comparisons of oral gabapentin and placebo, performed by the same investigators. The trials enrolled 355 participants with ALS: 80 in the gabapentin group and 72 in the placebo group in the first (phase II) trial and 101 in the gabapentin group and 102 in the placebo group in the second (phase III) trial. Neither trial was long enough to report survival at one year, which was our primary outcome. We found little or no difference in estimated one-year survival between the treated group and the placebo group (78% versus 77%, P = 0.63 by log-rank test; high-quality evidence). We also found little or no difference in the rate of decline of MVIC expressed as arm megascore, or rate of FVC decline (high-quality evidence). One trial investigated monthly decline in the ALSFRS and quality of life measured using the 12-Item Short Form Survey (SF-12) and found little or no difference between groups (moderate-quality evidence). The trials reported similar adverse events. Complaints that were clearly elevated in those taking gabapentin, based on analyses of the combined data, were light-headedness, drowsiness, and limb swelling (high-quality evidence). Fatigue and falls occurred more frequently with gabapentin than with placebo in one trial, but when we combined the data for fatigue from both trials, there was no clear difference between the groups. We assessed the overall risk of bias in the included trials as low. AUTHORS' CONCLUSIONS: According to high-quality evidence, gabapentin is not effective in treating ALS. It does not extend survival, slow the rate of decline of muscle strength, respiratory function and, based on moderate-quality evidence, probably does not improve quality of life or slow monthly decline in the ALSFRS. Other GABA modulators have not been studied in randomized trials.

Postnatal behavioral and inflammatory alterations in female pups prenatally exposed to valproic acid.

In Autism Spectrum Disorders (ASD), a bias to a higher incidence in boys than in girls has been reported. With the aim to identify biological mechanisms acting in female animals that could underlie this bias, we used an extensively validated mouse model of ASD: the prenatal exposure to valproic acid (VPA). We found postnatal behavioral alterations in female VPA pups: a longer latency in righting reflex at postnatal day (P) 3, and a delay in the acquisition of the acoustic startle response. We also analyzed the density of glial cells in the prefrontal cortex, hippocampus and cerebellum, in VPA and control animals. Female VPA pups showed alterations in the density of astrocytes and microglial cells between P21 and P42, with specific dynamics in each brain region. We also found a decrease in histone 3 acetylation in the cerebellum of female VPA pups at P14, suggesting that the changes in glial cell density could be due to alterations in the epigenetic developmental program. Finally, no differences in maternal behavior were found. Our results show that female VPA pups exhibit behavioral and inflammatory alterations postnatally, although they have been reported to have normal levels of sociability in adulthood. With our work, we contribute to the understanding of biological mechanisms underlying different effects of VPA on male and female rodents, and we hope to help elucidate whether there are factors increasing susceptibility to ASD in boys and/or resilience in girls.

[CONVULSIVE EFFECTS OF ANTIEPILEPTIC AGENTS]. / AZ ANTIEPILEPTIKUMOK PROKONVULZÍV HATÁSAI.

Antiepileptic drugs can provoke and worsen seizures, what is called paradoxical effect. Paradoxical seizure worsening can occur as a nonspecific manifestation of drug intoxication in number of antiepileptic drugs. The other type is a specific type, when antiepileptic drugs with pure GABAergic and sodium channel blocker mechanism of action provoke myoclonic, absence and atonic seizures in specific epilepsy syndromes, mainly in idiopathic generalized epilepsies. Antiepileptic drug-induced exacerbation of seizures is a common, often unrecognized clinical problem, which can be avoided by a careful syndromic diagnosis and by using broad spectrum antiepileptic drugs.

Sodium valproate for the treatment of Tourette׳s syndrome in children: a systematic review and meta-analysis.

The aims are to evaluate the efficacy and safety of sodium valproate for children with Tourette׳s syndrome (TS). We searched PubMed, EMBASE, the Cochrane library, Cochrane Central, CBM, CNKI, VIP, WANG FANG database and relevant reference lists. Five RCTs (N=247) and five case series (N=163) studies were included. Only one RCT (93 patients) evaluated total YGTSS scores and there was significant difference in the reduction of total YGTSS scores between sodium valproate and the control group (3.50±4.59 vs 7.86±7.03, P<0.01). One RCT (30 patients) evaluated motor and vocal tics, and there was significant difference in the reduction of motor and vocal tics scores between sodium valproate and haloperidol (10.45±4.15 vs 14.92±3.01, P<0.01). Meta-analysis of three RCTs (N=124) showed there was no significant difference in the reduction of the number of tics between sodium valproate and the positive control group [Relative Risk (RR)=1.09, 95%CI (0.92, 1.30), P=0.30]. The pooled proportion in five case series studies which used tics symptom improvement self-defined by authors was 80.7% (95% CI: 73.7-86.2, I(2)=0). No fatal side effects were reported. In conclusion, based on the limited evidence, the routine use of sodium valproate for treatment of TS in children is not recommended. Further well-conducted trials that examine long-term outcomes are required.

Normoammonemic encephalopathy: solely valproate induced or multiple mechanisms?

A 77-year-old woman presented with subacute onset progressive confusion, aggression, auditory hallucinations and delusions. In the preceding months, the patient had a number of admissions with transient unilateral hemiparesis with facial droop, and had been started on valproate for presumed hemiplegic migraine. Valproate was withdrawn soon after admission and her cognitive abilities have gradually improved over 3 months of follow-up. Valproate levels taken prior to withdrawal were subtherapeutic and the patient was normoammonaemic. EEG undertaken during inpatient stay showed changes consistent with encephalopathy, and low titre N-methyl-D-aspartate (NMDA) receptor antibodies were present in this patient. The possible aetiologies of valproate-induced encephalopathy and NMDA receptor-associated encephalitis present a diagnostic dilemma. We present a putative combinatorial hypothesis to explain this patient's symptoms.

Interaction of valproic acid and the antidepressant drugs doxepin and venlafaxine: analysis of therapeutic drug monitoring data under naturalistic conditions.

Valproic acid and the antidepressants doxepin and venlafaxine are frequently used psychotropic drugs. In the literature, an influence of valproic acid on serum levels of antidepressants has been described, although studies have focused on amitriptyline. The authors assessed their therapeutic drug monitoring (TDM) database for patients receiving a combination of doxepin or venlafaxine and valproic acid and compared these samples with matched controls without valproic acid comedication in terms of the serum concentration of antidepressants. The mean dose-corrected serum concentration of doxepin+N-doxepin in 16 patients who received valproic acid comedication was higher (2.171±1.482 ng/ml/mg) than that in the matched controls (0.971±0.857 ng/ml/mg, P<0.003). We also found a significant correlation between valproic acid serum level and dose-corrected doxepin+N-doxepin serum level (Spearman's ρ r=0.602, P<0.014). The mean dose-corrected serum level of venlafaxine+O-desmethylvenlafaxine in 41 patients who received valproic acid comedication did not differ significantly from that of the matched controls (P<0.089), but there was a significant difference between both groups in the dose-corrected serum level of O-desmethylvenlafaxine (1.403±0.665 vs. 1.102±0.444, P<0.017). As a consequence, if a combination of valproic acid with doxepin or venlafaxine is administered, cautious dosing is advisable and TDM should be performed.

Sodium valproate induced tremor in a patient with epilepsy and Down's syndrome.

Some papers reported the development of adverse drug reactions in patients with Down's syndrome during the treatment with antiepileptic drugs. However, at this time, no data have been published concerning the development of tremor in patients with Down's syndrome treated with sodium valproate. We report a 17-year-old man with epilepsy and Down's syndrome who experienced tremor during the treatment with a low dosage of sodium valproate. The Naranjo probability scale documented a possible association between tremor and sodium valproate. Sodium valproate was changed to lamotrigine with both a rapid improvement of tremor and an optimal control of symptoms. In conclusion we documented that sodium valproate is able to induce in a patient with epilepsy and Down's syndrome, the development of tremor probably through the decreased activity of GABAergic neurotrasmission; however, further studies may be performed in order to validate this observation.

Long-term follow-up for efficacy and safety of treatment of retinitis pigmentosa with valproic acid.

AIMS: The purpose of this study was to determine the long-term efficacy and safety of valproic acid (VPA) treatment in patients with pigmentary retinal dystrophies. METHODS: A retrospective chart review was conducted on 31 patients with a diagnosis of pigmentary retinal dystrophy prescribed VPA at a single centre. Visual field (VF), visual acuity (VA), length of treatment, liver enzymes and side effects were analysed. VF areas were defined using Goldmann VF (GVF) tracings recorded before, during and after VPA treatment using the V4e isopter for each eye. Using custom software, planimetric areas of VF were calculated. RESULTS: Five of the patients (10 eyes) had two Goldmann VF tracings, allowing comparison between baseline and follow-up VF. After 9.8 months of VPA, VF decreased by 0.145 cm(2) (26.478%) (p=0.432). For 22 of the patients (41 eyes), VA data was available, and logarithm of the minimum angle of resolution (logMAR) score changed by 0.056 log units (representing a decline in VA) after 14.9 months on VPA (p=0.002). Twelve patients (38.7%) reported negative side effects related to VPA use. CONCLUSIONS: VPA plays a complex role in patients with pigmentary retinal dystrophies and may be associated with VA and field decline as well as adverse side effects. Physicians should use caution with using VPA for pigmentary retinal dystrophies.