What is the treatment for involuntary tremors?

Treatment of Involuntary Tremors

For essential tremor, start with propranolol 80-240 mg/day or primidone as first-line therapy, which are effective in up to 70% of patients. 1

Initial Assessment and Classification

Before initiating treatment, categorize the tremor based on three key characteristics:

• Activation condition: Determine if the tremor occurs at rest (Parkinsonian), with maintained posture (postural), or during movement (kinetic/action tremor) 2, 3
• Body distribution: Note whether tremor is unilateral, bilateral, affects upper extremities, head, voice, or other body parts 2
• Frequency: Essential tremor typically presents at 4-8 Hz, while Parkinsonian tremor occurs at 4-6 Hz 4

Essential Tremor Treatment Algorithm

First-Line Medications

Propranolol remains the most established medication for essential tremor, having been used for over 40 years with demonstrated efficacy. 1

• Propranolol: 80-240 mg/day, most effective first-line option 1, 5
• Primidone: Alternative first-line therapy with similar efficacy 1
• Only initiate medications when tremor interferes with function or quality of life 1

Beta-Blocker Alternatives

If propranolol is contraindicated or not tolerated:

• Nadolol: 40-320 mg daily 1
• Metoprolol: 25-100 mg extended release daily or twice daily 1
• Timolol: 20-30 mg/day 1
• Atenolol: Limited evidence but may provide moderate effect 1

Critical Contraindications for Beta-Blockers

Avoid beta-blockers in patients with chronic obstructive pulmonary disease, bradycardia, or congestive heart failure. 1, 5

• In elderly patients, excessive heart rate reduction may lead to serious adverse events 1
• Common adverse effects include fatigue, depression, nausea, dizziness, insomnia, cold extremities, and bronchospasm 1
• Clinical pearl: For patients with both essential tremor and hypertension, beta-blockers provide dual benefits 1, 5

Second-Line Therapy

• Carbamazepine: May be used when first-line therapies fail, though generally less effective 1
• Gabapentin: Limited evidence for moderate efficacy 1

Parkinsonian Tremor Treatment

For Parkinson's disease tremor, carbidopa/levodopa combination therapy remains the first-line approach. 4, 6

Dosing Strategy

• Initial dosing: Start with carbidopa/levodopa 25 mg/100 mg three times daily 7
• Provide at least 70-100 mg of carbidopa per day 7
• Increase by one tablet every day or every other day as needed, up to eight tablets daily 7
• Anticholinergics may also be effective for parkinsonian rest tremor 4

Critical Warning

Monitor closely for involuntary movements (dyskinesias), which occur more rapidly with carbidopa/levodopa than with levodopa alone. 7

• Blepharospasm may be an early sign of excess dosage 7
• If involuntary movements develop, reduce dosage immediately 7

Neuroleptic Malignant Syndrome Risk

When reducing or discontinuing carbidopa/levodopa, observe carefully for hyperpyrexia and confusion, especially if patient is receiving neuroleptics. 7

• NMS is characterized by fever, muscle rigidity, involuntary movements, altered consciousness, autonomic dysfunction, and elevated creatine phosphokinase 7
• This is an uncommon but life-threatening syndrome requiring immediate recognition 7

Enhanced Physiologic Tremor

For enhanced physiologic tremor triggered by anxiety, caffeine, or stress, propranolol 80-240 mg/day is the most effective first-line treatment. 5

Non-Pharmacological Approaches

• Reduce caffeine consumption 5
• Avoid strenuous exercise before precision tasks 5
• Implement stress reduction techniques 5
• Use rhythm modification techniques: superimpose alternative rhythms on existing tremor and gradually slow movement to complete rest 1, 5

Cerebellar/Intentional Tremor

Intentional tremor presents as coarse, irregular tremor that worsens during goal-directed movements with a characteristic "wing-beating" appearance. 8

• Associated with dysarthria and ataxic gait 8
• Common causes include multiple sclerosis, Wilson's disease, traumatic brain injury, and certain medications 8
• Isoniazid may control cerebellar tremor associated with multiple sclerosis 6

Drug-Induced and Medication-Related Tremors

Antipsychotic-Induced Tremors

For antipsychotic-induced parkinsonism with tremor, use anticholinergic or mild dopaminergic agents (amantadine). 9

• Acute dystonic reactions respond well to anticholinergic or antihistaminic medications 9
• Consider prophylactic antiparkinsonian agents in patients at risk for acute dystonias, especially young males on high-potency antipsychotics 9

Tardive Dyskinesia

If tardive dyskinesia develops, continue medication only if patient is in full remission and dose changes would precipitate relapse; otherwise, lower dose or switch to atypical antipsychotic. 9

• Monitor with Abnormal Involuntary Movement Scale every 3-6 months 9
• Up to 50% of youth receiving neuroleptics may experience some form of tardive or withdrawal dyskinesia 9

Surgical Options for Refractory Tremor

When medications fail due to lack of efficacy at maximum doses, side effects, or contraindications, consider surgical therapies. 1

Magnetic Resonance-Guided Focused Ultrasound (MRgFUS)

MRgFUS thalamotomy shows sustained tremor improvement of 56% at 4 years with the lowest complication rate (4.4%) compared to radiofrequency thalamotomy (11.8%) and deep brain stimulation (21.1%). 1, 5

• Preferred for unilateral tremor or patients with medical comorbidities 1
• Early adverse effects include gait disturbance (36%) and paresthesias (38%), decreasing to 9% and 14% by 1 year 1
• Serious adverse events are rare (1.6%) 1

Contraindications for MRgFUS:

• Cannot undergo MRI 1, 5
• Skull density ratio <0.40 1, 5
• Bilateral treatment needed 1, 5
• Contralateral to previous thalamotomy 1

Deep Brain Stimulation (DBS)

For bilateral tremor or patients with contraindications to MRgFUS, DBS targeting the ventral intermediate nucleus (VIM) of the thalamus provides adjustable, reversible tremor control. 1

• Preferred for relatively young patients as it offers adjustable treatment 1
• Higher complication rate (21.1%) than MRgFUS but allows optimization over time 1
• Requires inpatient admission for careful post-operative monitoring 1

Radiofrequency Thalamotomy

• Available but carries higher complication risks (11.8%) than MRgFUS 1, 5
• Generally not preferred given availability of safer alternatives 1

Monitoring and Follow-Up

• Assess tremor severity and medication side effects regularly 1
• Adjust doses based on clinical response and tolerability 1
• If first-line agents fail, switch to or add second-line medications before considering surgical options 1

Common Pitfalls to Avoid

• Do not prescribe aids and equipment for functional tremor in the acute phase, as they may interrupt normal automatic movement patterns 1, 5
• Avoid cocontraction or tensing of muscles as a long-term strategy 1
• Do not use gross movements instead of fine movements for activities like handwriting 1
• For orthostatic tremor, consider clonazepam as specific treatment 6
• For alcohol withdrawal tremor, propranolol may be useful 6