Elevated peripheral levels of receptor-interacting protein kinase 1 (RIPK1) and IL-8 as biomarkers of human amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating fatal neurodegenerative disease with no cure. Receptor-interacting protein kinase 1 (RIPK1) has been proposed to mediate pathogenesis of ALS. Primidone has been identified as an old drug that can also inhibit RIPK1 kinase. We conducted a drug-repurposing biomarker study of primidone as a RIPK1 inhibitor using SOD1G93A mice and ALS patients. SOD1G93A mice treated with primidone showed significant delay of symptomatic onset and improved motor performance. One-hundred-sixty-two ALS participants dosed daily with primidone (62.5 mg) completed 24-week follow-up. A significant reduction was showed in serum levels of RIPK1 and IL-8, which were significantly higher in ALS patients than that of healthy controls (P < 0.0001). Serum RIPK1 levels were correlated positively with the severity of bulbar symptoms (P < 0.05). Our study suggests that serum levels of RIPK1 and IL-8 in peripheral can be used as clinical biomarkers for the activation of RIPK1 in central nervous system in human ALS patients. Repurposing primidone may provide a promising therapeutic strategy for ALS. The effect of primidone for the treatment of other inflammatory diseases may also be considered, since the activation of RIPK1 has been implicated in mediating a variety of inflammatory diseases including COVID-19-associated cytokine release syndrome (CRS). (ChiCTR2200060149).

[Essential Tremor That is Difficult to Improve with Standard Medical Treatment-Suppression: Excluding Surgical Treatment]

For essential tremors that are refractory to standard medical treatment, surgical treatment is considered when there is obstruction in activities of daily living. However, there are patients who do not wish to undergo or are contraindicated for surgical treatment. In this paper, we explored what is considered to be the standard medical treatment and when surgery cannot be performed. In Japan, medical treatment is based on the use of arotinolol and primidone, and combination therapy and second-line drugs are extensively discussed. Furthermore, an algorithm of the treatment for essential tremors in Japan has been provided.

Current and Future Neuropharmacological Options for the Treatment of Essential Tremor

BACKGROUND

Essential Tremor (ET) is likely the most frequent movement disorder. In this review, we have summarized the current pharmacological options for the treatment of this disorder and discussed several future options derived from drugs tested in experimental models of ET or from neuropathological data.

METHODS

A literature search was performed on the pharmacology of essential tremors using PubMed Database from 1966 to July 31, 2019.

RESULTS

To date, the beta-blocker propranolol and the antiepileptic drug primidone are the drugs that have shown higher efficacy in the treatment of ET. Other drugs tested in ET patients have shown different degrees of efficacy or have not been useful.

CONCLUSION

Injections of botulinum toxin A could be useful in the treatment of some patients with ET refractory to pharmacotherapy. According to recent neurochemical data, drugs acting on the extrasynaptic GABAA receptors, the glutamatergic system or LINGO-1 could be interesting therapeutic options in the future.

Essential Tremor

Essential tremor is one of the most common movement disorders. It is characterized by a bilateral action tremor of the upper limbs. It may be accompanied by tremor of the head, voice, or lower limbs. Essential tremor is often present for years or decades before presentation and it progresses insidiously. It is often familial and transiently responsive to alcohol. For patients requiring treatment, the two first-line medications are propranolol and primidone, which are synergistic. Patients with disabling essential tremor that cannot be managed medically are candidates for either deep brain stimulation or focused ultrasound.

Clinical and cognitive profiles of patients with both Parkinson's disease and essential tremor

Although Parkinson's disease (PD) and essential tremor (ET) are distinct clinical disorders, their coexistence can sometimes cause diagnostic problems. In this study, we conducted detailed investigations of patients with both ET and PD (ET-PD) and compared their clinical and cognitive profiles with those of patients with only ET or only PD. This study examined three groups of patients: the first group had ET-PD concomitantly (n = 9); the second group had only ET (n = 9); the third group had only PD (n = 10). The groups were compared in terms of demographic characteristics, clinical features, and cognitive functions. With the exception of positive family histories, which were more common in ET-PD than in PD patients, we found no differences among the groups with respect to demographic characteristics (p = 0.044). PD-only patients had more akinetic-rigid type Parkinsonism (p = 0.016), and their levodopa response was better than that of ET-PD patients (p = 0.017). Patients with ET-PD obtained significantly lower scores than those with pure ET on several cognitive tests, suggesting a prominent frontal-type cognitive dysfunction. In conclusion ET-PD patients differed from PD patients, showing more frequent familial tremor histories and lower levodopa responsiveness. This patient population also demonstrated more severe cognitive impairments than pure-ET patients. This result suggests that ET-PD patients are a subset of ET patients with more widespread neurodegeneration, which may indicate the presence of a syndrome that includes overlap between ET and PD.

Zebrafish larvae exposed to ginkgotoxin exhibit seizure-like behavior that is relieved by pyridoxal-5'-phosphate, GABA and anti-epileptic drugs

The etiology of epilepsy is a very complicated, multifactorial process that is not completely understood. Therefore, the availability of epilepsy animal models induced by different mechanisms is crucial in advancing our knowledge and developing new therapeutic regimens for this disorder. Considering the advantages of zebrafish, we have developed a seizure model in zebrafish larvae using ginkgotoxin, a neurotoxin naturally occurring in Ginkgo biloba and hypothesized to inhibit the formation of the neurotransmitter γ-aminobutyric acid (GABA). We found that a 2-hour exposure to ginkgotoxin induced a seizure-like behavior in zebrafish larvae. This seizure-like swimming pattern was alleviated by the addition of either pyridoxal-5'-phosphate (PLP) or GABA and responded quickly to the anti-convulsing activity of gabapentin and phenytoin, two commonly prescribed anti-epileptic drugs (AEDs). Unexpectedly, the ginkgotoxin-induced PLP depletion in our experimental setting did not affect the homeostasis of folate-mediated one-carbon metabolism, another metabolic pathway playing a crucial role in neural function that also relies on the availability of PLP. This ginkgotoxin-induced seizure behavior was also relieved by primidone, which had been tested on a pentylenetetrazole-induced zebrafish seizure model but failed to rescue the seizure phenotype, highlighting the potential use and complementarity of this ginkgotoxin-induced seizure model for AED development. Structural and morphological characterization showed that a 2-hour ginkgotoxin exposure did not cause appreciable changes in larval morphology and tissues development. In conclusion, our data suggests that this ginkgotoxin-induced seizure in zebrafish larvae could serve as an in vivo model for epileptic seizure research and potential AED screening.

What did STAR*D teach us? Results from a large-scale, practical, clinical trial for patients with depression

The authors provide an overview of the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study (www.star-d.org), a large-scale practical clinical trial to determine which of several treatments are the most effective "next-steps" for patients with major depressive disorder whose symptoms do not remit or who cannot tolerate an initial treatment and, if needed, ensuing treatments. Entry criteria were broadly defined and inclusive, and patients were enrolled from psychiatric and primary care clinics. All participants began on citalopram and were managed by clinic physicians, who followed an algorithm-guided acute-phase treatment through five visits over 12 weeks. At the end of each sequence, patients whose depression had not fully remitted were eligible for subsequent randomized trials in a sequence of up to three clinical trials. In general, remission rates in the study clinics were lower than expected, suggesting the need for several steps to achieve remission for most patients. There was no clear medication "winner" for patients whose depression did not remit after one or more aggressive medication trials. Both switching and augmenting appeared to be reasonable options when an initial antidepressant treatment failed, although these two strategies could not be directly compared. Further, the likelihood of remission after two vigorous medication trials substantially decreased, and remission would likely require more complicated medication regimens for which the existing evidence base is quite thin. STAR*D demonstrated that inclusion of more real-world patients in clinical trials is both feasible and informative. Policy implications of the findings, as well as the study's limitations, are discussed.

Biochemical variables related to calcium metabolism in epileptics

Five biochemical variables, S-Ca, U-Ca, S-P, U-P and S-ALP, all involved in calcium metabolism, have been investigated in 86 epileptics on long-term medication. We found hypocalciuria in half of the epileptics and increased S-ALP in one third. In contrast to earlier reports there was no hypocalcemia, whereas hypercalcemia was found in 7 epileptics. We have previously reported a high frequency of fractures in these epileptics. An increased fracture rate was found in the 13 epileptics with both hypocalciuria and increased S-ALP, indicating osteomalacia.

Drugs in the treatment of tinnitus

Many drugs and some foods can cause or aggravate tinnitus in some patients. These substances should be identified and withdrawn. Tinnitus may be improved by the treatment of associated conditions, infections, or hearing loss with appropriate drugs--hypotensives, antibiotics, vasodilators, fluoride or thyroxine. Intravenous lignocaine can temporarily reduce or abolish tinnitus in many patients but can aggravate existing tinnitus in some and may have no effect on others. Analogy with pain of central origin suggests that the beneficial effects of lignocaine (lidocaine) may be due to its anticonvulsant action. Lignocaine is used as a test to distinguish between different mechanisms of tinnitus and to predict responses to oral anticonvulsants. Dramatic responses with lignocaine are usually associated with cochlear hearing loss and often with comparable though less marked responses to oral anticonvulsants. Patients who do not benefit from lignocaine do not respond to oral anticonvulsants. The action of anticonvulsants is often potentiated by tricyclic antidepressants. The majority of patients who respond to lignocaine can also have their tinnitus effectively masked, as predicted, on a tinnitus synthesizer. A small proportion respond to masking and not to lignocaine and a small proportion to lignocaine and not to masking. Beneficial effects of masking and anticonvulsants are cumulative. Anticonvulsants may also produce subjective improvement in clarity, improved tolerance of hearing aids and increased masking benefit when a hearing aid is worn.

Transient improvement of essential tremor during electroconvulsive therapy

We present a patient who demonstrated transient yet significant improvement of essential tremor (ET) during electroconvulsive therapy. To our knowledge, this is the first such report. The improvement lasted during the course of electroconvulsive therapy and was of a similar magnitude to that which she had experienced on a first-line medication for ET. We discuss the potential pathophysiological implications of this observation in light of recent histopathologic findings in patients with ET.

[Diagnosis and treatment of tremor in Parkinson's disease and essential tremor]

For patients presenting predominantly or purely with tremor, the correct diagnosis of tremor-dominant Parkinson's disease (PD) versus essential tremor (ET) is very important for prognosis and effective therapy. ET tremor is usually characterized by symmetric bilateral postural and kinetic tremor, which may respond to low alcohol consumption. Many patients have a family history of ET tremors. Medical treatment with primidone or beta-blockers effectively controls ET tremor, but in many cases no treatment is needed at all. The typical tremor form of PD is an asymmetric rest tremor, which is treated with dopaminergic agents such as levodopa. Differential diagnosis of ET and PD may be difficult in a subset of PD patients who present with additional postural and kinetic tremor and in a minority of ET patients who show a clear asymmetry of their postural and kinetic tremor. In some patients with ET, the tremor can later become severe and even require treatment with deep brain stimulation.

Essential tremor

INTRODUCTION

Essential tremor is one of the most common movement disorders throughout the world, with prevalence in the general population of 0.4-3.9%. Although most people with essential tremor are only mildly affected, those who seek medical care are disabled to some extent, and most are socially handicapped by the tremor.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical question: What are the effects of drug treatments in people with essential tremor of the hand? We searched: Medline, Embase, The Cochrane Library and other important databases up to December 2006 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 41 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: adding mirtazepine to other antitremor drugs; benzodiazepines; beta-blockers other than propranolol; botulinum A toxin-haemagglutinin complex; calcium channel blockers; carbonic anhydrase inhibitors; clonidine; flunarizine; gabapentin; isoniazid; Phenobarbital; primidone; propranolol; and topiramate.

Phenytoin desensitization in a child with symptomatic localization-related epilepsy

We reported a child with refractory partial seizures successfully managed by clinical desensitization to phenytoin. The patient had ischemic brain lesions due to cardiopulmonary arrest at 39 weeks of corrected age. He had complex partial seizures refractory to several antiepileptic drugs since 4 years of age. At 8 years 1 month of age, phenytoin was first administered. Fever and maculopapular rashes appeared at 10 days after phenytoin initiation, and then the drug was discontinued. At 8 years 8 months of age, desensitization was attempted because of refractoriness of seizures to drugs other than phenytoin. Desensitization was started at 1mg daily, and then the dose was doubled every week. His seizures were controlled by 150mg/day of phenytoin in combination with primidone. No problems have been observed during desensitization.

Tremor

Tremor ist eines der häufigsten neurologischen Symptome. Die genaue Diagnose wird in der Regel klinisch gestellt. Der häufigste primär neurologisch bedingte Tremor ist der Essentielle Tremor (Prävalenz 2–5%), der sich überwiegend als relativ symmetrischer Halte- und kinetischer Tremor zeigt. Er folgt in 60% der Fälle einem autosomal dominanten Erbgang, bessert sich bei 60–70% der Patienten unter Alkohol und kann außer den Händen den Kopf und die Stimme betreffen. Der Parkinson-Tremor tritt dagegen überwiegend in Ruhe auf und beginnt asymmetrisch, häufig unter Beteiligung von Beinen und Gesicht. Der cerebelläre Tremor ist ein Intentionstremor. Der hochfrequente Orthostatische Tremor betrifft hauptsächlich die Beine und führt zu einer Standunsicherheit. Der Dystone Tremor ist ein Aktionstremor der betroffenen Körperregion. Die symptomatische medikamentöse Therapie des Tremors wird in erster Linie von der klinischen Erscheinungsform bestimmt. Während Halte- und Aktionstremores hauptsächlich auf nicht-selektive Betablocker (Propranolol), Primidon, manche neuere Antiepileptika (Gabapentin, Topiramat) und Benzodiazepine ansprechen, bessern sich klassische Ruhetremores unter dopaminergen Substanzen (Levodopa, Dopaminagonisten) oder Anticholinergika. Beim Dystonen Tremor sind häufig Botulinum-Toxin Injektionen erfolgreich, der orthostatische Tremor spricht bei einem Teil der Patienten auf Gabapentin oder Benzodiazepine an. Für medikamentös therapierefraktäre, schwer behinderte Patienten besteht bei der Mehrzahl der Tremores die Möglichkeit der Implantation von Stimulationselektroden in den VIM-Kern des Thalamus mit sehr guten Erfolgen aber vorhandenen Risiken.

Essential tremor-the most common movement disorder in older people

Essential tremor (ET) affects approximately 4% of the population above 65 years of age. The traditional view that ET is a familial monosymptomatic disorder with a benign prognosis has recently been challenged, as it is now known to be a progressive and clinically heterogeneous condition with sporadic and familial forms. The pathogenesis of ET is not fully understood, though a disordered central mechanism is the most likely site of origin with possible modulation by muscle adrenoreceptors. The limited post-mortem studies have not shown consistent abnormalities in the brains of ET patients. ET is often misdiagnosed as Parkinson's disease, particularly in the older population. Tremor amplitude increases with age, accounting for substantial disability in older people. Current therapy (drugs and neurosurgery) has significant limitations in older people. A better understanding of its pathophysiology in the future will help in developing more effective therapy, including neuroprotective strategies.

Pharmacological treatment of disabling tremor

Tremor is often a disabling primary condition or secondary to another disorder. No universally effective pharmacological agent exists for the treatment of essential tremor, and patients differ greatly in their response to therapies, thus requiring individualised regimens. Deep brain stimulation is the best option for patients with disabling, drug-resistant essential tremor. Resting tremor in Parkinson's disease is usually not the primary disabling feature, and in most cases, levodopa/carbidopa is satisfactory for many years. Young Parkinson's patients with dominant, disabling tremor benefit from anticholinergics in addition to dopaminergic therapies. However, older Parkinson's patients with more disabling tremor may suffer from dose-dependent side effects, and deep brain stimulation should be considered. This article outlines the available pharmacological agents and treatment considerations for various disabling tremors, including essential tremor and Parkinson's disease.

Is primidone the drug of choice for epileptic patients with QT-prolongation? A comprehensive analysis of literature

Sudden unexplained/unexpected death (SUDEP) in epilepsy is a major cause of death accounting for 7-17% of the mortality among epileptic patients. Prolongation of QT-interval has been issued as a major mechanism in SUDEP since it is associated with fatal cardiac arrhythmias. This condition may be further precipitated by anti-epileptic treatment. Despite thorough literature research, we did not find any reports suggesting that primidone is responsible for QT-prolongation. On the contrary, all the retrieved reports addressed that the drug shortened QT-interval and corrected signs and symptoms of the underlying disease.

Rhythmic EMG and EEG activity during voluntary movement in posthypoxic cortical action myoclonus

A patient with posthypoxic cortical action myoclonus was studied using polygraphic EEG-EMG recording techniques and transcranial magnetic stimulation. The myoclonic jerks were not stimulus-sensitive, and were not associated with enhancement of the somatosensory evoked potential (SEP). The most prominent electrophysiological finding was that rhythmic EMG activity was produced when the patient attempted rapid voluntary movement. EEG-EMG polygraph indicated that the rhythmic EMG activity was preceded by rhythmic activity in the EEG recorded overlying the contralateral central region. The frequency of both EEG and EMG activity was the same (approximately 50 Hz). Treatment using a combination of clonazepam, carbamazepine and primidone diminished the action myoclonus, concomitant with the disappearance of the rhythmic EEG and EMG activity. In the sensorimotor cortex of the normal monkey and humans, oscillatory activity ranging between 20-50 Hz has been recorded in the local field potential. Our findings suggest that cortical hyperoscillation may produce this characteristic rhythmic EEG and EMG activity and may, in turn, be related to cortical action myoclonus.

Primidone is associated with interictal depression in patients with epilepsy

Depressive symptoms are common in epilepsy. To determine associations between depression and demographic, clinical, and pharmacological factors among epileptic patients, we conducted a cross-sectional survey. We evaluated 241 epileptic outpatients at a neurological center in a 6-month period. Depressive syndrome was diagnosed when both the Montgomery-Asberg Scale and the Beck Depression Inventory were rated above the standard cutoff points. Bivariate and multivariate analyses were performed to assess the differences between depressed and nondepressed patients with respect to demographic, clinical, and pharmacological features. Depressive syndrome was diagnosed in 42.7% of patients (n=103). Factors associated in the bivariate analysis were: cryptogenic etiology, posttraumatic epilepsy, use of primidone, and inadequate seizure control. After logistic regression, inadequate seizure control (OR 3.08, 95% CI 1.40-6.77, P=0.005) and use of primidone (OR 4.08, 95% CI 2.09-7.98; P<0.001) remained significantly associated. Depression was common and associated with inadequate seizure control and use of primidone.

Epilepsy in the United Kingdom: seizure frequency and severity, anti-epileptic drug utilization and impact on life in 1652 people with epilepsy

OBJECTIVES

To describe the clinical characteristics of epilepsy in a representative sample of the UK population, including seizure frequency and severity; overall severity of epilepsy; patterns of anti-epileptic drug (AED) use; and the impact of epilepsy on patients' lives. Secondly, to determine if these characteristics differ according to age.

METHOD

A large, geographically comprehensive survey of people with epilepsy by means of a postal questionnaire distributed by general practitioners to 3455 unselected patients receiving AEDs for epilepsy, regardless of age or type of epilepsy and including all regions of the UK. Data were collected on age and gender; age of onset of seizures; seizure frequency and severity; AED use and adverse effect levels; and impact on life of epilepsy. Sub-analyses were performed with stratification by epilepsy severity and age-group.

RESULTS

There were 1652 completed replies. The mean age was 44.2 years; there were 47.2% males, 48.5% females (4.4% not recorded). The mean age at first seizure, 25.1 years, and the mean duration of epilepsy, 19.7 years, were comparable with previous studies. In the preceding one year, 51.7% of patients had no seizures; 7.9% one seizure, 17.2% 2-9 seizures and 23.2% 10 or more. Sixty-four percent of patients had epilepsy classified as mild and 32% severe. There was a marked and significant decrement of seizure frequency with increasing age. The most commonly used AEDs were carbamazepine (37.4%), valproate (35.7%), phenytoin (29.4%), phenobarbitone or primidone (14.2%) and lamotrigine (10.3%). Monotherapy was used in 68% of patients. Patients taking multiple AEDs reported significantly higher levels of adverse effects and worse seizure control. The major impacts of epilepsy on life were work and school difficulties, driving prohibition, psychological and social life. The impacts listed varied with the epilepsy severity and age.

CONCLUSIONS

Seizures remain uncontrolled in up to half of all people with epilepsy in the UK with significant impact on work, family and social life. Previously, there has been a deficiency of data on the characteristics of epilepsy in older people, although it is recognized that the condition is of increasing epidemiological importance in this age group. We have found clear differences in the clinical characteristics of epilepsy in older people, particularly that seizure frequency appears to decline with increasing age.

Anticonvulsant efficacy of the low-affinity partial benzodiazepine receptor agonist ELB 138 in a dog seizure model and in epileptic dogs with spontaneously recurrent seizures

PURPOSE

Ataxia, sedation, amnesia, ethanol and barbiturate potentiation, loss of efficacy (tolerance), development of dependence, and the potential for drug abuse limit the clinical use of benzodiazepines (BZDs) for long-term treatment of epilepsy or anxiety. BZD ligands that are in current use act as full allosteric modulators of gamma-aminobutyric acid (GABA)-gated chloride channels and, on long-term administration, trigger a functional uncoupling between the GABAA and BZD recognition sites. Partial allosteric modulators, which have a low intrinsic activity at the BZD recognition site of the GABAA receptor, might eventually overcome the limitations of full agonists such as diazepam (DZP).

METHODS

In the present study, the new low-affinity partial BZD-receptor agonist ELB 138 [former name AWD 131-138; 1-(4-chlorophenyl)-4-morpholino-imidazolin-2-one] was evaluated in a dog seizure model and in epileptic dogs with spontaneously recurrent seizures.

RESULTS

ELB 138 was shown to increase potently the pentylenetetrazole (PTZ) seizure threshold in dogs. Prolonged oral administration with twice-daily dosing of ELB 138 with either 5 or 40 mg/kg over a 5-week period was not associated with loss of anticonvulsant efficacy in the PTZ dog model. To study whether physical dependence developed during long-term treatment, the BZD antagonist flumazenil was injected after 5 weeks of treatment with ELB 138. Compared with prolonged treatment with DZP, only relatively mild abstinence symptoms were precipitated in dogs treated with ELB 138, particularly at the lower dosage (5 mg/kg, b.i.d.). In a prospective trial in dogs with newly diagnosed epilepsy, ELB 138 markedly reduced seizure frequency and severity without significant difference to standard treatments (phenobarbital or primidone) but was much better tolerated than the standard drugs. In dogs with chronic epilepsy, most dogs exhibited a reduction in seizure frequency and severity during add-on treatment with ELB 138.

CONCLUSIONS

The data demonstrate that the partial BZD receptor agonist ELB 138 exerts significant anticonvulsant efficacy without tolerance in a dog seizure model as well as in epileptic dogs with spontaneously recurrent seizures. These data thus substantiate that partial agonism at the BZD site of GABAA receptors offers advantages versus full agonism and constitutes a valuable approach for treatment of seizures.

Levetiracetam in Focal Epilepsy and Hepatic Porphyria: A Case Report

We report a patient with focal epilepsy and latent hereditary coproporphyria who had exacerbation of clinical symptoms of porphyria under treatment with valproate and primidone and was then treated with levetiracetam without exacerbation of clinically latent porphyria.

Essential tremor: diagnosis and treatment

Essential tremor is a common movement disorder in adults that interferes with the performance of functional and social activities. Differentiation of essential tremor from other tremor syndromes is important in order to provide appropriate patient education and therapy. The mainstays of pharmacotherapy are propranolol and primidone; however, in selected patients, agents such as alcohol, benzodiazepines, botulinum toxin, and gabapentin may provide symptomatic benefits. Advances in surgical interventions, such as stereotactic thalamotomy and thalamic deep brain stimulation, offer patients an alternative treatment modality when pharmacotherapy is inadequate. A treatment algorithm is provided to guide clinicians in the management of patients with essential tremor.

[Antiepileptic primidone shortly to be withdrawn from sale: change medication now]

The antiepileptic drug primidone is to be withdrawn from sale by January 2004. After this date, the drug will still be available for a time, but only on a limited basis. Most primidone users are elderly patients who have been prescribed this drug for many years. Changing to a new drug constitutes a health risk for them. If primidone treatment is discontinued too quickly, withdrawal seizures may appear, some of which may be severe. In patients who have not suffered an epileptic seizure for many years, discontinuing medication may be considered. Whenever continuation of anticonvulsive treatment is desirable, it may probably be a good idea to switch over to some newer antiepileptic drug. If a simple and quick substitution is essential, primidone may be replaced by its main metabolite: phenobarbital. General practitioners and neurologists are strongly advised to alter patients' medication in good time.

Low Doses of Topiramate are Effective in Essential Tremor: A Report of Three Cases

We here report on 3 patients with essential tremor, otherwise unresponsive to pharmacological treatment, who greatly benefited from low doses of topiramate (50 mg/d). No side effects were observed and improvement was sustained during a mean of 7 months (range 3-12 months) follow up. Our results suggest that topiramate titration should be performed gradually, so as not to neglect cases responsive to low doses.

Use of primidone in low doses (250 mg/day) versus high doses (750 mg/day) in the management of essential tremor. Double-blind comparative study with one-year follow-up

Essential tremor is the most common involuntary movement; we studied 113 affected subjects (54 men, 59 women) with an average age of 63.9 years and average duration of 9.05 years. These patients participated in a double-blind study with a 1-year follow-up to compare treatment efficiency using primidone dosages of 250 mg/day (G 250, 56 patients) versus 750 mg/day (G 750, 57 patients). The study was designed with an 80% power and 95% confidence level. The statistical analysis used was an ANOVA (with Bonferroni multiple comparison test corrections); a value of p<0.004 was accepted as significant. To compare other values, a chi-square test was used; p<0.05 was considered significant. To evaluate the efficacy of the drug, clinical protocol employed the 'clinical evaluation scale for tremor'. All of the patients were evaluated a total of 13 times, once prior to the introduction of primidone and the other 12 evaluations following the initiation of the treatment. Eighty-seven patients completed the study: 15 patients abandoned the study due to undesirable side effects, five due to negative response, and six who were lost to follow-up. The percentage of patients who didn't complete the study was significantly higher in the group that received 750 mg/day of primidone (p<0.04) and more frequent as well in this same group, due to undesirable side effects (p<0.03). The patients of both G250 and G750 showed a significant improvement in each of the controls compared to the basal value (p<0.0001). No significant differences (p<0.06) were found when the averages of the evaluations of each group were compared. These responses were maintained during the entire treatment period. Low doses of primidone (250 mg/day) were equally or more effective than high doses (750 mg/day) in the control of essential tremor; this response was maintained for 12 months and furthermore, demonstrated fewer undesirable effects.

Benefits and risks of pharmacological treatments for essential tremor

Essential tremor can cause significant functional disability in some patients. The arms are the most common body part affected and cause the most functional disability. The treatment of essential tremor includes medications, surgical options and other forms of therapy. Presently there is no cure for essential tremor nor are there any medications that can slow the progression of tremor. Treatment for essential tremor is recommended if the tremor causes functional disability. If the tremor is disabling only during periods of stress and anxiety, propranolol and benzodiazepines can be used during those periods when the tremor causes functional disability. The currently available medications can improve tremor in approximately 50% of the patients. If the tremor is disabling, treatment should be initiated with either primidone or propranolol. If either primidone or propranolol do not provide adequate control of the tremor, then the medications can be used in combination. If patients experience adverse effects with propranolol, occasionally other beta-adrenoceptor antagonists (such as atenolol or metoprolol) can be used. If primidone and propranolol do not provide adequate control of tremor, occasionally the use of benzodiazepines (such as clonazepam) can provide benefit. Other medications that may be helpful include gabapentin or topiramate. If a patient has disabling head or voice tremor, botulinum toxin injections into the muscles may provide relief from the tremor. Botulinum toxin in the hand muscles for hand tremor can result in bothersome hand weakness and is not widely used. There are other medications that have been tried in essential tremor and have questionable efficacy. These drugs include carbonic anhydrase inhibitors (e.g. methazolamide), phenobarbital, calcium channel antagonists (e.g. nimodipine), isoniazid, clonidine, clozapine and mirtazapine. If the patient still has disabling tremor after medication trials, surgical options are usually considered. Surgical options include thalamotomy and deep brain stimulation of the thalamus. These surgical options provide adequate tremor control in approximately 90% of the patients. Surgical morbidity and mortality for these procedures is low. Deep brain stimulation and thalamotomy have been shown to have comparable efficacy but fewer complications have been reported with deep brain stimulation. In patients undergoing bilateral procedures deep brain stimulation of the thalamus is the procedure of choice to avoid adverse effects seen with bilateral ablative procedures. The use of medication and/or surgery can provide adequate tremor control in the majority of the patients.

Tremor

PURPOSE OF REVIEW

Tremors can be encountered in a variety of disease states but the most common causes are Parkinson disease and essential tremor. This review was undertaken to highlight advances in the field during the last 12 months.

RECENT FINDINGS

Kinetic tremor may be more prominent in essential tremor than postural tremor. Clinically Parkinson disease and essential tremor may be confused with each other but it may be possible to distinguish between these two nitrites using sophisticated electrophysiology. Monosymptomatic rest tremor has recently been shown to be associated with decreased fluorodopa uptake on the positron emission tomography scan suggesting its relationship to Parkinson disease.

SUMMARY

Significant advances have been made in the understanding of the pathophysiology, genetics and therapy of tremor disorders during the last 12 months. This review will consider Parkinson disease, essential tremor and other tremors and highlight advances in the field.

Essential tremor: differential diagnosis and current therapy

Essential tremor is a common movement disorder that affects between 5 and 10 million persons in the United States. It is characterized primarily by an action and postural tremor most often affecting the arms, but it can also affect other body parts. Essential tremor is a progressive neurologic disorder and can cause substantial disability in some patients. Although there is no cure for essential tremor, pharmacologic and surgical treatments can provide some benefit. Primidone and propranolol are first-line treatments. Other medications with potential efficacy include benzodiazepines, gabapentin, topiramate, and botulinum toxin. Patients with medication-resistant tremor may benefit from thalamotomy or deep brain stimulation of the thalamus. The use of medical and surgical therapies can provide benefit in up to 80% of patients with essential tremor.

Tremor--easily seen but difficult to describe and treat

Tremor is a common movement disorder yet many physicians struggle with its terminology as well as with its treatment. Attempts have been made to develop standard terminology and criteria for tremors but this process continues to evolve. In this review, a summary of the currently-proposed phenomenology and syndromic classification of all types of tremor is presented. The diagnosis and management of essential tremor is presented in more detail, as it is the most commonly encountered tremor.

Unverricht-Lundborg disease with cystatin B gene abnormalities

The clinical, neurophysiologic, and genetic findings in two Japanese patients with the Unverricht-Lundborg type of progressive myoclonus epilepsy are described. The cystatin B gene of Patient 1 exhibited expansion of the dodecamer (12-mer) repeat located in the 5' region and a point mutation (G-->A mutation) in exon 2. The cystatin B gene of Patient 2 exhibited homozygous expansion of the dodecamer repeat. Both parents of Patient 2 were heterozygous carriers. The two patients had a similar clinical course, and their symptoms were similar to those of previously reported patients in Finland. They both had a good response to zonisamide and low-dose primidone. We recommend that zonisamide and low-dose primidone should be introduced as the first drugs of choice for the treatment of patients with the Unverricht-Lundborg type of progressive myoclonus epilepsy.