Essential tremor

Overview

General background | Focus of the review | Comments on evidence | Search and appraisal summary | Substantive changes at this update | Abstract | Cite as

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General background

Essential tremor is a disabling neurological disorder. Although most people with essential tremor are only mildly affected, it can be very disabling as the disease progresses and can cause physical and psychosocial impairment. Essential tremor commonly interferes with physical activities, including writing, using a computer, fixing small things, dressing, eating, and holding reading material.

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Focus of the review

A review of evidence for interventions for essential tremor is helpful for healthcare providers when considering the many possible medications available as well as other types of treatment, including deep brain stimulation. We have decided to focus this overview on some of the more commonly used pharmacological therapies for essential tremor because drug therapies are usually offered as initial therapy.

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Comments on evidence

Overall, we found few RCTs assessing the long-term effects of drug treatments. Many of the trials we found were small, short term, and were crossover in design. In addition, most of the trials were old, with few published recently.

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Search and appraisal summary

The update literature search for this overview was carried out from the date of the last search, December 2006, to January 2014. For more information on the electronic databases searched and criteria applied during assessment of studies for potential relevance to the overview, please see the Methods section. Searching of electronic databases retrieved 56 studies. After deduplication and removal of conference abstracts, 31 records were screened for inclusion in the overview. Appraisal of titles and abstracts led to the exclusion of 18 studies and the further review of 13 full publications. Of the 13 full articles evaluated, two RCTs were added at this update.

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Additional information

All medications have a trade-off between benefit and side effects. For example, propranolol can cause depression and hypotension, primidone can cause problems with initial titration and the side effects can be difficult to manage, and alprazolam has abuse potential. Adverse effects may be particularly difficult to manage in older patients. Propranolol and primidone are recommended in clinical guidelines as the first-line pharmacological therapy for essential tremor, but still a significant portion of patients might not respond. There are also multiple medications that have not been found beneficial for tremor. More effective pharmacological therapy is needed.

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Substantive changes at this update

Alprazolam New option. Two RCTs added that were included in a previous version of this overview.[8][9] Categorised as 'unknown effectiveness'.

Beta-blockers other than propranolol Evidence re-evaluated. No new evidence found. Categorisation unchanged (unknown effectiveness).

Botulinum A toxin-haemagglutinin complex Evidence re-evaluated. Categorisation unchanged (trade-off between benefits and harms).

Clonazepam New option. One RCT added that was included in a previous version of this overview.[23] Categorised as 'unknown effectiveness'.

Diazepam New option. No evidence found. Categorised as 'unknown effectiveness'.

Gabapentin Evidence re-evaluated. No new evidence found. Categorisation unchanged (unknown effectiveness).

Levetiracetam New option. Two RCTs added.[27][28] Categorised as 'unknown effectiveness'.

Lorazepam New option. No evidence found. Categorised as 'unknown effectiveness'.

Phenobarbital Evidence re-evaluated. No new evidence found. Categorisation changed from 'trade-off between benefits and harms' to 'unknown effectiveness'.

Primidone Evidence re-evaluated. No new evidence found. Categorisation changed from 'trade-off between benefits and harms' to 'likely to be beneficial'.

Propranolol Evidence re-evaluated. No new evidence found. Categorisation unchanged (likely to be beneficial).

Sodium oxybate New option. No evidence found. Categorised as 'unknown effectiveness'.

Topiramate Evidence re-evaluated. No new evidence found. Categorisation unchanged (trade-off between benefits and harms).

Abstract

INTRODUCTION: Essential tremor is one of the most common movement disorders in the world, with prevalence in the general population of 0.4% to 3.9%. METHODS AND OUTCOMES: We conducted a systematic overview, aiming 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 January 2014 (BMJ Clinical Evidence overviews are updated periodically; please check our website for the most up-to-date version of this overview). RESULTS: At this update, searching of electronic databases retrieved 56 studies. After deduplication and removal of conference abstracts, 31 records were screened for inclusion in the overview. Appraisal of titles and abstracts led to the exclusion of 18 studies and the further review of 13 full publications. Of the 13 full articles evaluated, two RCTs were added at this update. We performed a GRADE evaluation for 11 PICO combinations. CONCLUSIONS: In this systematic overview, we categorised the efficacy for 13 interventions based on information about the effectiveness and safety of alprazolam, beta-blockers other than propranolol, botulinum A toxin-haemagglutinin complex, clonazepam, diazepam, gabapentin, levetiracetam, lorazepam, phenobarbital, primidone, propranolol, sodium oxybate, and topiramate.

Cite as

Zesiewicz TA, Kuo S. Essential tremor. Systematic review 1206. BMJ Clinical Evidence. . 2015 December. Accessed [date].