Successful Treatment of Primary Orthostatic Tremor Using Perampanel

Non-Persistence of Tremorolytic Effect of Perampanel in Essential Tremor: Real-World Experience with 50 Patients

Background

We describe our experience of using perampanel to treat essential tremor (ET) over 12 months.

Methods

We enrolled 50 ET patients in an open-label trial. Perampanel was titrated to 4 mg/day as adjuvant therapy. The main outcome measures were baseline, +1, +3, +6, and + 12 month scores of the Tremor Clinical Rating Scale (TCRS) and the Glass scale (GS).

Results

Twenty patients withdrew because of adverse effects. At +1 month, 27 of 30 patients improved: 68% reduction in both TCRS 1 + 2 (P < 0.001) and TCRS 3 (P < 0.001); TCRS 4 + 1.8 and GS 1.1 point reduction. By +12 months non-persistence of therapeutic effect occurred in 70% of patients: the mean reduction in TCRS 1 + 2 was 33% (P = 0.03), TCRS 3 (0.04), TCRS 4 + 0.8, GS 0.2 points reduction.

Conclusions

We report important peramapanel acute tremorolytic effects, but poor tolerance to adverse effects and a non-sustained therapeutic effect in most patients.

Remarkable improvement of primary orthostatic tremor using perampanel

Management of primary orthostatic tremor (POT) remains challenging, and medication is often ineffective.

We report the case of a 53-year-old female with orthostatic tremor for 6 years who was refractory to gabapentin, clonazepam, primidone and propranolol. After treatment with 4 mg/day perampanel, she reported almost complete resolution of tremor. The diagnosis of POT was confirmed by tremor analysis using surface electromyography.

Our report shows the potential use of the novel AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor antagonist perampanel for the treatment of POT. To date, only two similar patients, one refractory to treatment and the other previously treated with clonazepam only, have been reported. We would like to note that our patient was refractory to all previous therapy and responded to a low dose of perampanel without side effects. The striking clinical improvement suggests a putative role of glutamate in the pathophysiology of orthostatic tremor.

Primary Orthostatic Tremor: Experience of Perampanel Use in 20 Patients

Background

Primary orthostatic tremor (POT) is a rare disorder for which current treatments are largely ineffective. Following up on our recent report of complete resolution of POT symptoms in a patient using low doses of perampanel, we describe our experience of perampanel in 20 patients.

Methods

Twenty patients whose neurologists prescribed perampanel were recruited. Initial dose was 2 mg/day, which was increased to 4 mg/day after the first month. Treatment efficacy was self-scored from +3 to -3 at 1 and 3 months.

Results

Eight patients withdrew due to adverse effects. Of the 12 patients who completed the study, 92% indicated that their POT symptoms had improved after 1 month, with 75% indicating moderate to marked improvement (mean score 1.9 ± 0.9). This improvement was not sustained by follow-up at 3 months (mean score 0.9 ± 1.3). A rebound of POT symptoms that lasted 2-6 weeks was observed in most patients who withdrew.

Discussion

Our experience with this series of cases points to the potential of low-dose perampanel as a treatment for POT, although poor tolerance and the possibility of a non-persistent therapeutic benefit need to be considered. Controlled studies are needed to confirm these findings.