To conduct a literature review using real-world evidence on the most common pharmacotherapies used in treating essential tremor (ET).

ET is among the most common movement disorders in the US. Current treatments include pharmacological treatments and surgical interventions, though many patients continue to lack adequate tremor control. Syntheses of published real-world evidence on ET pharmacotherapies are lacking.

We conducted a comprehensive literature review of English-language studies published between 1966-2022 using PubMed. The review targeted non-clinical trial studies of adults with ET evaluating propranolol, primidone, gabapentin, and/or topiramate, and reporting at least upper limb tremor efficacy, safety/adverse events, tolerability, and/or treatment patterns. Studies reporting ≤10 subjects were excluded.

We identified 236 studies. Following title and abstract screening, 75 full-text studies were assessed, with 15 included in data extraction. Patient- or clinician-validated scales were used in 2/15 studies. Activities of daily living and quality of life outcomes were not commonly reported. Up to 81% and 55% of patients used propranolol and primidone, respectively. Gabapentin (30%) and topiramate (20%) were used less frequently. Though clinical response definitions varied, propranolol demonstrated response in 37-56% of patients, and primidone in 43-55% of patients among studies with ≥50 evaluable patients. Approximately one-quarter of patients reported responding to gabapentin or topiramate. Discontinuation rates varied widely across studies, from 10-70% for both propranolol and primidone. Gabapentin and topiramate had discontinuation rates from 26-86% and 26-58%, respectively. Usage, efficacy, and discontinuation were not characterized by line of therapy (i.e. initial vs subsequent treatments) in the assessed studies.

Currently available ET pharmacotherapies may not provide adequate efficacy for many patients, highlighting substantial unmet need. We identified several gaps in the published evidence base, including evaluation of commonly-used ET medications by line of therapy and reporting on validated measures to enable comparisons to new ET pharmacotherapies.