Flunarizine in essential tremor

Cinnarizine- and flunarizine-associated movement disorder: a literature review

Introduction

Cinnarizine (CNZ) and flunarizine (FNZ) belong to the calcium channel blockers class of medication.

Main text

The aim of this literature review is to evaluate the clinical epidemiological profile, pathological mechanisms, and management of CNZ/FNZ-associated movement disorder (MD). Relevant reports in six databases were identified and assessed by two reviewers without language restriction. One hundred and seventeen reports containing 1920 individuals who developed a CNZ/FNZ-associated MD were identified. The MD encountered were 1251 parkinsonism, 23 dyskinesias, 11 akathisia, 16 dystonia, and 5 myoclonus, and in the group not clearly defined, 592 extrapyramidal symptoms, 19 tremors, 2 bradykinesia, and 1 myokymia. The predominant sex was female with a percentage of 72.69% (466/641). The mean age was 74.49 (SD, 7.88) years. The mean CNZ dose was 148.19 mg (SD, 42.51) and for the FNZ dose, 11.22 mg (5.39). The mean MD onset and recovery were 1.83 years (SD, 1.35) and 3.71 months (SD, 1.26). In the subgroup of subjects that had improvement of the symptoms, the complete recovery was achieved within 6 months of the drug withdrawal in almost all subjects (99%). The most common management was drug withdrawal. A complete recovery was observed in 93.77% of the patients (437/466).

Conclusions

CNZ/FNZ-associated MD was extensively reported in the literature. Parkinsonism was the most well described. Myoclonus (MCL) was the poorest described MD with missing data about the neurological examination and electrodiagnostic studies. The knowledge of this disorder probably can contribute to the understanding of the other drug-induced MDs.

Current and Emerging Treatments of Essential Tremor

Established medications that improve tremor include beta-adrenergic antagonists, primidone, topiramate, and ethanol. Less consistent efficacy is reported with many other medications, usually antiepileptic drugs. A number of investigational medications, including T-type calcium channel blockers and allosteric gamma-aminobutyric acid-A modulators, are being developed for tremor. Deep brain stimulation techniques continues to be refined and focused ultrasound thalamotomy now offers an incisionless surgical option. Finally a number of peripheral electrical and mechanical devices are under development for tremor.

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.

Evidence-based guideline update: treatment of essential tremor: report of the Quality Standards subcommittee of the American Academy of Neurology

BACKGROUND

This evidence-based guideline is an update of the 2005 American Academy of Neurology practice parameter on the treatment of essential tremor (ET).

METHODS

A literature review using MEDLINE, EMBASE, Science Citation Index, and CINAHL was performed to identify clinical trials in patients with ET published between 2004 and April 2010.

RESULTS AND RECOMMENDATIONS

Conclusions and recommendations for the use of propranolol, primidone (Level A, established as effective); alprazolam, atenolol, gabapentin (monotherapy), sotalol, topiramate (Level B, probably effective); nadolol, nimodipine, clonazepam, botulinum toxin A, deep brain stimulation, thalamotomy (Level C, possibly effective); and gamma knife thalamotomy (Level U, insufficient evidence) are unchanged from the previous guideline. Changes to conclusions and recommendations from the previous guideline include the following: 1) levetiracetam and 3,4-diaminopyridine probably do not reduce limb tremor in ET and should not be considered (Level B); 2) flunarizine possibly has no effect in treating limb tremor in ET and may not be considered (Level C); and 3) there is insufficient evidence to support or refute the use of pregabalin, zonisamide, or clozapine as treatment for ET (Level U).

Essential tremor

Essential tremor (ET) is among the most common neurologic disorders. The traditional view of this disorder as a benign, monosymptomatic, familial condition is being replaced by a more complex view of ET as perhaps a family of diseases with etiologic, clinical, and pathologic heterogeneity. This article discusses the major clinical features of ET and approaches to its diagnosis and treatment.

Essential tremor: Treatment options

The treatment of essential tremor depends on the tremor severity, location, and risk benefit ratios. Mild to moderate tremor usually will respond to oral agents such as noncardiac selective beta-blockers or primidone. Other agents including ethanol, topiramate, benzodiazepines, gabapentin, levetiracetam, and zonisamide may be effective. There are very little data comparing different oral agents, but there is support for polypharmacy in some cases. Botulinum toxin injections are effective in some tremor patterns, especially wrist flexion/extension and head tremor. For severe tremor, surgical lesioning or deep brain stimulation of the thalamus is justified and often dramatically improves function.

Uso do propranolol de ação prolongada em 40 pacientes com tremor essencial e virgens de tratamento: um ensaio clínico não controlado

O tremor essencial (TE) é o distúrbio do movimento mais frequente. Entre os tratamentos de primeira escolha está o uso de beta-bloqueadores. O objetivo deste trabalho é relatar os resultados do uso de propranolol de ação prolongada (PAP) em 40 pacientes com TE e virgens de tratamentos anteriores. MÉTODO: 40 pacientes com TE foram submetidos a um protocolo de avaliação pré-estabelecido em que constavam escalas de classificação para o tremor e escalas de avaliação da severidade do tremor. Todos os pacientes foram submetidos a avaliação inicial e após 1 mês de tratamento. RESULTADOS: com relação ao tipo de tremor, 36 pacientes (90% do total) tinham o tipo 2; os tipos 3 e 4 ocorreram em dois pacientes cada (10% do total). Houve história familiar de tremor em 25 casos (62,5%). A média de idade dos pacientes foi 43,1 anos e a média de idade de início dos sintomas foi 27,4 anos. Dos 40 indivíduos avaliados, 33 ou 82,5% apresentaram algum grau de melhora com PAP; em 52,5 % a melhora foi considerada ótima ou boa. CONCLUSÃO: o PAP mostrou ser uma medicação adequada para o tratamento do TE nesta amostra de 40 pacientes avaliados.