Use of antiepileptic drugs for hyperkinetic movement disorders

Post-stroke Movement Disorders: Clinical Spectrum, Pathogenesis, and Management

Involuntary movements develop after 1-4% of strokes and they have been reported in patients with ischemic and hemorrhagic strokes affecting the basal ganglia, thalamus, and/or their connections. Hemichorea-hemiballism is the most common movement disorder following a stroke in adults while dystonia is most common in children. Tremor, myoclonus, asterixis, stereotypies, and vascular parkinsonism are other movement disorders seen following stroke. Some of them occur immediately after acute stroke, some can develop later, and others may have delayed onset progressive course. Proposed pathophysiological mechanisms include neuronal plasticity, functional diaschisis, and age-related differences in brain metabolism. There are no guidelines regarding the management of post-stroke movement disorders, mainly because of their heterogeneity.

Paroxysmal Genetic Movement Disorders and Epilepsy

Paroxysmal movement disorders include paroxysmal kinesigenic dyskinesia, paroxysmal non-kinesigenic dyskinesia, paroxysmal exercise-induced dyskinesia, and episodic ataxias. In recent years, there has been renewed interest and recognition of these disorders and their intersection with epilepsy, at the molecular and pathophysiological levels. In this review, we discuss how these distinct phenotypes were constructed from a historical perspective and discuss how they are currently coalescing into established genetic etiologies with extensive pleiotropy, emphasizing clinical phenotyping important for diagnosis and for interpreting results from genetic testing. We discuss insights on the pathophysiology of select disorders and describe shared mechanisms that overlap treatment principles in some of these disorders. In the near future, it is likely that a growing number of genes will be described associating movement disorders and epilepsy, in parallel with improved understanding of disease mechanisms leading to more effective treatments.

Anti-epileptic activity, toxicity and teratogenicity in CD1 mice of a novel valproic acid arylamide derivative, N-(2-hydroxyphenyl)-2-propylpentanamide

N-(2-hydroxyphenyl)-2-propylpentamide (HO-AAVPA) is a novel arylamide derivative of valproic acid (VPA) designed in silico, with better antioxidant and antiproliferative effect on cancer cell lines than VPA. This study was aimed to evaluate the anticonvulsant activity, the toxicity and teratogenicity produced in HO-AAVPA-treated CD1 mice using VPA as positive control. With the maximal electroshock (MES)- and pentylenetetrazole (PTZ)-induced seizure models, HO-AAVPA reduced the time of hind limb extension, stupor and recovery, the number of clonic and tonic seizures and the mortality rate in a dose-dependent manner, obtaining an ED₅₀ of 370 and 348 mg/kg for MES and PTZ, respectively. On the rotarod test, mice administered with 600 mg/kg HO-AAVPA manifested reduced locomotor activity (2.78%); while HO-AAVPA at 300 mg/kg and VPA at 500 mg/kg gave a similar outcome (∼60%). The LD₅₀ of 936.80 mg/kg herein found for HO-AAVPA reflects moderate toxicity. Concerning teratogenicity, the administration of HO-AAVPA to pregnant females at 300 and 600 mg/kg on gestation day (GD) 8.5 generated less visceral and skeletal alterations in the fetuses, as well as, minor rate of modifications in the expression pattern of the neuronal marker Tuj1 and endothelial marker PECAM1 in embryos, that those induced by VPA administration. Altered embryonic development occurred with less frequency and severity with HO-AAVPA at 600 mg/kg than VPA at 500 mg/kg. In conclusion, the protective effect against convulsions provided by HO-AAVPA was comparable to that of VPA in the MES and PZT seizure models, showed lower toxicity and less damage to embryonic and fetal development.

Treatment of Chorea in Childhood

Chorea is a movement disorder characterized by ongoing random-appearing sequences of discrete involuntary movements or movement fragments. Chorea results from dysfunction of the complex neuronal networks that interconnect the basal ganglia, thalamus, and related frontal lobe cortical areas. The complexity of basal ganglia circuitry and vulnerability of those circuits to injury explains why chorea results from a wide variety of conditions. Because etiology-specific treatments or effective symptomatic treatments are available for causes of chorea, defining the underlying disease is important. The treatment of chorea can be considered in three main categories: (1) terminating or modifying exposure to the causative agent, (2) symptomatic treatment of chorea, and (3) treatment targeting the underlying etiology. Symptomatic treatment decision of chorea should be based on the functional impact on the child caused by chorea itself. There have been no reported randomized, placebo-controlled trials of symptomatic treatment for chorea in childhood. Thus the recommendations are based on clinical experience, case reports, expert opinions, and small comparative studies. Better knowledge of mechanisms underlying childhood chorea will provide more etiology-based treatments in the future.

Phenytoin Induced Chorea: A Rare Adverse Effect of the Drug

BACKGROUND

Dyskinetic neurological diseases are common presentations of adverse reaction to many therapeutic agents. Phenytoin, a widely used age-old antiepileptic drug has been reported to cause dyskinesias, a rare Adverse Drug Reaction (ADR) in adults with toxic therapeutic serum level. When the drug is used in combination with other drugs which augments free drug level of phenytoin or in patients of organic brain lesion, this side effect is very occasionally reported with even normal therapeutic drug level.

CLINICAL CASE

We report a case of young male presented with chorea after two months of starting phenytoin for primary generalised epilepsy with normal therapeutic serum drug level. After excluding other differentials, drug-induced chorea was the final diagnosis. Despite phenytoin level was in therapeutic range, we have a trial of stopping Phenytoin with complete disappearance of chorea in 3 days. On reintroduction of phenytoin in the same dose, there was the reappearance of chorea in onemonth re-emphasising the diagnosis as "phenytoin-induced chorea".

CONCLUSION

If any patient on phenytoin develops any new neurological feature including dyskinesias, it should be considered as an ADR despite drug serum level within the normal therapeutic range.

Punding following posterior cerebral artery infarction: a case report and literature review

INTRODUCTION

Punding is a complex stereotyped behavior, characterized by excessiveness, non-goal orientation, and repetitiveness. It is mostly associated with Parkinson's disease, and very few cases in non-Parkinson's disease have been reported. We report a case of punding associated with supratentorial ischemic stroke.

CASE PRESENTATION

We present a 70-year-old man with left posterior cerebral artery infarction with quetiapine-induced punding manifesting as repetitive unidirectional body turning. Remission of punding behavior ensued after cessation of quetiapine and administration of clonazepam.

CONCLUSION

This case describes the clinical course of quetiapine-induced punding in a patient with left posterior cerebral artery infarction. It suggests clonazepam may serve as a treatment option for poststroke punding.

Control of Granule Cell Dispersion by Natural Materials Such as Eugenol and Naringin: A Potential Therapeutic Strategy Against Temporal Lobe Epilepsy

The hippocampus is an important brain area where abnormal morphological characteristics are often observed in patients with temporal lobe epilepsy (TLE), typically showing the loss of the principal neurons in the CA1 and CA3 areas of the hippocampus. TLE is frequently associated with widening of the granule cell layer of the dentate gyrus (DG), termed granule cell dispersion (GCD), in the hippocampus, suggesting that the control of GCD with protection of hippocampal neurons may be useful for preventing and inhibiting epileptic seizures. We previously reported that eugenol (EUG), which is an essential component of medicinal herbs and has anticonvulsant activity, is beneficial for treating epilepsy through its ability to inhibit GCD via suppression of mammalian target of rapamycin complex 1 (mTORC1) activation in the hippocampal DG in a kainic acid (KA)-treated mouse model of epilepsy in vivo. In addition, we reported that naringin, a bioflavonoid in citrus fruits, could exert beneficial effects, such as antiautophagic stress and antineuroinflammation, in the KA mouse model of epilepsy, even though it was unclear whether naringin might also attenuate the seizure-induced morphological changes of GCD in the DG. Similar to the effects of EUG, we recently observed that naringin treatment significantly reduced KA-induced GCD and mTORC1 activation, which are both involved in epileptic seizures, in the hippocampus of mouse brain. Therefore, these observations suggest that the utilization of natural materials, which have beneficial properties such as inhibition of GCD formation and protection of hippocampal neurons, may be useful in developing a novel therapeutic agent against TLE.

Movement Disorders Following Cerebrovascular Lesions: Etiology, Treatment Options and Prognosis

Post-stroke movement disorders are uncommon, but comprise an important part of secondary movement disorders. These exert variable and heterogeneous clinical courses according to the stroke lesion and its temporal relationships. Moreover, the predominant stroke symptoms hinder a proper diagnosis in clinical practice. This article describes the etiology, treatment options and prognosis of post-stroke movement disorders.

Drug utilisation study in patients receiving antiepileptic drugs in Colombia

INTRODUCTION

This study examines the indications according to which antiepileptic drugs are prescribed and used in a population of patients enrolled in the Colombian national health system (SGSSS).

METHODS

Retrospective cross-sectional study. From the pool of individuals in 34 Colombian cities who used antiepileptic drugs between 18 July, 2013 and 31 August, 2014 during a period of no less than 12 months, we obtained a random sample stratified by city. Socio-demographic, pharmacological and comorbidity variables were analysed. Continuous and categorical variables were compared, and logistic regression models were used.

RESULTS

Our patient total was 373 patients, with 197 women (52.1%) and a mean age of 41.9 ± 21.7 years; 65.4% of the patients were treated with monotherapy. The most frequently used drugs were valproic acid (53.1%) and carbamazepine (33.2%). Epilepsy was the most frequent indication (n=178; 47.7%); however, 52.3% of the patients were prescribed antiepileptics for different indications, especially neuropathic pain (26.8%), affective disorders (14.2%) and migraine prophylaxis (12.3%). A total of 81 patients with epilepsy (46.6%) displayed good seizure control while another 25 (14.4%) had drug-resistant epilepsy. In the multivariate analysis, medication adherence was associated with a lower risk of treatment failure in patients with epilepsy (OR: 0.27; 95%CI, 0.11-0.67).

CONCLUSIONS

In Colombia, antiepileptic drugs are being used for indications other than those originally intended. Monotherapy is the most commonly used treatment approach, together with the use of classic antiepileptic drugs.

Effects of phenobarbital and levetiracetam on PR and QTc intervals in patients with post-stroke seizure

BACKGROUND AND OBJECTIVES

Sudden unexplained/unexpected death (SUDEP) is related to high mortality in patients with epilepsy. The prolongation of QT interval, involved in cardiac arrhythmia-related SUDEP, may be precipitated by antiepileptic drugs (AEDs). In this study, we evaluated the effects of phenobarbital and levetiracetam on PR-QTc intervals in patients with post-stroke seizures.

METHODS

We performed an open-label, parallel group, prospective, multicenter study between June 2009 and December 2013 in patients older than 18 years of age with a clinical diagnosis of post-stroke seizure and treated with phenobarbital or levetiracetam. In order to exclude a role of cerebral post-stroke injury on modulation of PR and QTc intervals, patients with cerebral post-stroke injury and without seizures were also enrolled as controls.

RESULTS

Interictal electrocardiography analysis revealed no significant difference in PR interval between patients treated with an AED (n = 49) and control patients (n = 50) (181.25 ± 12.05 vs. 182.4 ± 10.3 ms; p > 0.05). In contrast, a significantly longer QTc interval was recorded in patients treated with an AED compared with control patients (441.2 ± 56.6 vs. 396.8 ± 49.3 ms; p < 0.01). Patients treated with phenobarbital showed a significantly longer QTc interval than patients treated with levetiracetam (460.0 ± 57.2 vs. 421.5 ± 50.1 ms; p < 0.05).

CONCLUSIONS

The study reported that in patients with late post-stroke seizures, phenobarbital prolonged QTc interval more so than levetiracetam.

A review on antiepileptic drugs-dependent fatigue: pathophysiological mechanisms and incidence

Fatigue represents a common side effect of several drugs, however, the underlying mechanisms have not been well identified. A depression of the central nervous system (CNS) and/or changes in peripheral processes have been associated with the development of fatigue. Antiepileptic drugs (AEDs), generally decreasing CNS excitability, are used in the treatment of seizures as well as other neurological and psychiatric diseases. Fatigue is certainly a common AEDs' side effect, although a high degree of variability exists depending on both patients' characteristics and the drug used. Here, we delineate the pathophysiological central and peripheral mechanisms by which AEDs may cause fatigue also reviewing the available clinical data in order to assess a possible AEDs rank and highlight each AEDs related risk. It appears that drugs acting on the GABAergic system have the highest incidence (with tiagabine exception) of fatigue followed by Gabapentin and Levetiracetam whereas drugs mainly inhibiting sodium channels (Carbamazepine, Eslicarbazepine, Lamotrigine, Phenytoin and Valproate) have the lowest. However, the dose used, AEDs related side effects and patients' characteristics might influence the degree of fatigue observed.

Pathological laughter associated with paroxysmal kinesigenic dyskinesia: A rare presentation of acute disseminated encephalomyelitis

A 13-year-old boy presented with recurrent episodes of sudden brief posturing of the right upper and lower limbs accompanied by transient inability to speak and a tendency to smile which would sometimes break into laughter. Awareness was retained during the attack, and there was no associated emotional abnormality. The events were precipitated by walking and occurred several times in a day. The laughter was pathological in nature, and the abnormal posturing was akin to ‘paroxysmal kinesigenic dyskinesia’ (PKD). ‘Pathological laughter or crying’ is defined as an involuntary, inappropriate, unmotivated laughter, crying or both, without any associated mood change. It can occur as a result of cerebral lesions like tumors, trauma, vascular insults, multiple sclerosis and/or degenerative disorders. It can also be a component of gelastic epilepsy which is characterized by stereotyped recurrences, presence of interictal and ictal epileptiform discharges and absence of external precipitants. In our patient, however, there was no ictal or interictal EEG correlate. Paroxysmal kinesigenic dyskinesia is characterized by intermittent, involuntary movements triggered by kinesigenic stimuli and is usually familial but can also be secondary to metabolic and structural brain disorders. Magnetic Resonance Imaging (MRI), in our case, revealed multiple T2 and FLAIR hyperintense, non-enhancing lesions in the periaqueductal gray matter, pontine and midbrain tegmentum, bilateral thalami and left lentiform nucleus suggesting a diagnosis of ‘acute disseminated encephalomyelitis’, in which this unique combination of pathological laughter and PKD has not been described so far. Magnetic Resonance Spectroscopy (MRS) confirmed a demyelinating pathology, and the patient responded well to steroids.

Pharmacodynamic potentiation of antiepileptic drugs' effects by some HMG-CoA reductase inhibitors against audiogenic seizures in DBA/2 mice

It is known that the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are effective in both the primary and the secondary prevention of ischemic heart disease. Increasing evidence indicates that statins have protective effects in several neurological diseases including stroke, cerebral ischemia, Parkinson disease, multiple sclerosis, traumatic brain injury and epilepsy. The aim of the present research was to evaluate the effects of some HMG-CoA reductase inhibitors (i.e. lovastatin, simvastatin, atorvastatin, fluvastatin and pravastatin) commonly used for the treatment of hypercholesterolemia in the DBA/2 mice, an animal model of generalized tonic-clonic seizures. Furthermore, the co-administration of these compounds with some antiepileptic drugs (AEDs; i.e. carbamazepine, diazepam, felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, phenobarbital, phenytoin, topiramate and valproate) was studied in order to identify possible positive pharmacological interactions. Simvastatin only was active against both the tonic and clonic phase of audiogenic seizures, whereas the other statins tested were only partially effective against the tonic phase with the following order of potency: lovastatin>fluvastatin>atorvastatin; pravastatin was completely ineffective up to the dose of 150mg/kg. The co-administration of ineffective doses of all statins with AEDs generally increased the potency of the latter reducing their ED50 values. In particular, simvastatin was the most active in potentiating the activity of AEDs and the combinations of statins with carbamazepine, diazepam, felbamate, lamotrigine, topiramate and valproate were the most favorable, whereas, the co-administrations with the other AEDs studied was in most cases neutral. The increase in potency was generally associated with an enhancement of motor impairment (TD50); however, the therapeutic index (TD50/ED50) of combined treatment of AEDs with statins was predominantly more favorable than control. Statins administration did not significantly affect the total plasma but, in some cases, it increased the free plasma levels and the brain concentrations of some of the AEDs studied (i.e. carbamazepine, diazepam, phenytoin and valproate); however, these alterations where not statistically significant. Therefore, with the exception of the latter compounds, we might exclude pharmacokinetic interactions and conclude that for the most of AEDs, potentiation was of pharmacodynamic nature. In conclusion, simvastatin, fluvastatin, lovastatin and atorvastatin showed an additive anticonvulsant effect when co-administered with some AEDs, most notably carbamazepine, diazepam, felbamate, lamotrigine, topiramate and valproate, implicating a possible therapeutic relevance of such drug combinations. The present results suggest that statins, besides the beneficial cardiovascular effects, might be able to affect brain areas, which might participate in the regulation of seizure susceptibility.

Post-stroke Movement Disorders: Clinical Manifestations and Pharmacological Management

Involuntary abnormal movements have been reported after ischaemic and haemorrhagic stroke. Post stroke movement disorders can appear as acute or delayed sequel. At the moment, for many of these disorders the knowledge of pharmacological treatment is still inadequate. Dopaminergic and GABAergic systems may be mainly involved in post-stroke movement disorders. This article provides a review on drugs commonly used in post-stroke movement disorders, given that some post-stroke movement disorders have shown a partial benefit with pharmacological approach.

Antiepileptic drugs for central post-stroke pain management

Antiepileptic drugs (AEDs) are commonly prescribed for a wide range of disorders other than epilepsy, including both neurological and psychiatric disorders. AEDs play also a role in pharmacological management of neuropathic pain. Central post-stroke pain (CPSP) is a disabling morbidity occurring in 35% of patients with stroke. The pathophysiology of CPSP is not well known but central disinhibition with increased neuronal excitability has been suggested. AEDs include many different drugs acting on pain through several mechanisms, such as reduction of neuronal hyperexcitability. To our knowledge conclusive evidence has not been published yet. The aim of this review is to delineate efficacy and safety of AEDs in CPSP.

Effects of Carbamazepine/Oxycodone Coadministration in the Treatment of Trigeminal Neuralgia

OBJECTIVE:

To report on a patient with trigeminal neuralgia who responded positively to combined carbamazepine/oxycodone treatment.

CASE SUMMARY:

A 48-year-old woman with a 4-month history of left facial pain consisting of episodes lasting less than 5 minutes was brought to our institution for clinical evaluation. Clinical, laboratory, and neuroradiologic findings led to a diagnosis of idiopathic trigeminal neuralgia. Carbamazepine treatment was started at 200 mg every 12 hours and increased at discharge to 300 mg every 8 hours. Two weeks later the patient was readmitted with trigeminal neuralgia symptoms that had persisted since the previous admission, although they had decreased in intensity. Carbamazepine was reduced to 200 mg every 8 hours and oxycodone 5 mg every 12 hours was added to the treatment regimen, with a complete resolution of pain within 7 days.

DISCUSSION:

Pathophysiological mechanisms involved in both the genesis and the maintenance of trigeminal neuralgia have not yet been defined. Several hypotheses could explain this disorder, ranging from peripheral neural ectopic pacemaker to central disinhibition. Both the interruption of the sodium channel and the modulation of both κ-and μ-opioid receptors contributed to antinociceptive effects in trigeminal neuralgia.

CONCLUSIONS:

Treatment with a combination of carbamazepine, a sodium channel blocker, and oxycodone, a mixed κ-and μ-opioid receptor agonist, may be useful in alleviating symptoms of trigeminal neuralgia.