Primary Treatment for Orthostatic Tremor
Clonazepam is the first-line pharmacological treatment for orthostatic tremor, with gabapentin serving as an effective alternative, particularly in patients who fail to respond to or cannot tolerate clonazepam. 1, 2
Understanding Orthostatic Tremor
Orthostatic tremor is a rare disorder characterized by unsteadiness when standing still that rapidly improves with sitting or walking. 2 The diagnosis requires polygraphic recording demonstrating a pathognomonic high-frequency tremor of 13-18 Hz in the legs while standing. 1, 2 This condition typically begins in the sixth decade of life and is often underdiagnosed, with an average delay of 5.7 years from symptom onset to diagnosis. 3
First-Line Pharmacological Treatment
Clonazepam
- Clonazepam is widely used as the first-line agent for orthostatic tremor, though treatment response is often disappointing overall. 2
- The evidence supporting clonazepam comes primarily from clinical experience and case series rather than randomized controlled trials. 4
- Despite its widespread use, many patients do not achieve adequate symptom control with clonazepam alone. 5
Gabapentin as Primary Alternative
- Gabapentin demonstrates significant efficacy, with patients reporting 60-80% improvement (mean 73%) in symptoms. 5
- Effective dosing ranges from 300-1800 mg/day (mean 1030 mg/day). 5
- Side effects are generally mild, transient, and dose-related. 5
- In one series, 4 of 5 patients who had failed clonazepam responded well to gabapentin, with sustained benefit ranging from 2-22 months. 5
- Gabapentin should be considered in cases of clonazepam resistance or intolerable side effects. 1
Additional Treatment Considerations
Other Pharmacological Options
- Primidone may provide benefit in some patients, particularly those who fail first-line agents. 1
- Dopaminergic drugs may be helpful in selected cases, especially given evidence suggesting dopaminergic control of the central oscillator. 2, 3
- The association of orthostatic tremor with Parkinson's disease in approximately 10% of cases supports consideration of dopaminergic therapy in appropriate patients. 3
Deep Brain Stimulation
- Bilateral ventral intermediate nucleus deep brain stimulation shows promise for refractory cases that fail medical management. 4
- This should be reserved for patients with severe, treatment-resistant symptoms significantly impacting quality of life. 4
Important Clinical Pitfalls
Screen for "OT plus" syndrome: Approximately 25% of patients have additional neurological features, most commonly parkinsonism (15% of all cases), which may influence treatment selection. 3 In these cases, orthostatic tremor symptoms typically precede other neurological features by several years. 3
Manage expectations: Overall treatment response to all available medications is modest and inconsistent, with many patients experiencing relatively unchanged symptoms over years despite therapy. 3, 4 However, approximately 15% of patients experience gradual worsening with proximal spread to trunk and arms. 3
Confirm diagnosis with EMG: Surface electromyography demonstrating the characteristic 13-18 Hz tremor while standing is mandatory before initiating treatment, as clinical examination is otherwise typically normal except for unsteadiness that disappears with walking. 1, 2