What is the recommended treatment for essential tremors?

Treatment of Essential Tremor

Propranolol (80-240 mg/day) or primidone should be initiated as first-line treatment for essential tremor when symptoms interfere with function or quality of life, with both medications effective in up to 70% of patients. 1

First-Line Pharmacological Treatment

The American Academy of Neurology establishes propranolol and primidone as the two evidence-based first-line options for essential tremor 1. These medications have been used for over 40 years with demonstrated efficacy 1.

Key treatment principles:

• Only initiate medication when tremor interferes with function or quality of life 1
• Both propranolol and primidone reduce tremor severity by approximately 50% in responsive patients 2, 3
• If one agent fails, the other should be tried before moving to second-line options 1
• The two medications can be combined if monotherapy provides inadequate control 2

Propranolol Dosing and Mechanism

• Dosage range: 80-240 mg/day 1
• Works by blocking peripheral effects of adrenaline and modulating noradrenergic GABA outflow centrally 4
• Decreases corticospinal excitability and increases short afferent inhibition 4

Primidone Considerations

• Has intrinsic anti-tremor properties independent of its phenobarbital metabolite 1
• Clinical benefits may not appear for 2-3 months, requiring an adequate trial period 1
• Modulates GABA-A and GABA-B intracortical circuits and blocks voltage-gated sodium channels 4
• Better baseline cerebellar function (measured by eyeblink classical conditioning) predicts better response 4

Important Contraindications and Precautions

Beta-blockers like propranolol must be avoided in patients with: 1, 5

• Chronic obstructive pulmonary disease or asthma
• Bradycardia or heart block
• Congestive heart failure

Common adverse effects of beta-blockers include: 1

• Fatigue and depression
• Dizziness and hypotension
• Exercise intolerance and sleep disorders
• Cold extremities and bronchospasm

Primidone-specific concerns: 1

• Behavioral disturbances, irritability, and sleep disturbances at higher doses
• Teratogenic risks (neural tube defects) - counsel women of childbearing age

Clinical pearl: For patients with both essential tremor and hypertension, propranolol provides dual therapeutic benefits 1, 5

Second-Line Pharmacological Options

If first-line agents fail or are contraindicated, consider: 1, 2

• Carbamazepine - generally less effective than first-line therapies
• Gabapentin - limited evidence for moderate efficacy
• Topiramate - may provide benefit in selected cases 6
• Benzodiazepines (clonazepam) - can be helpful, particularly for stress-induced tremor 2

Alternative Beta-Blockers

If propranolol causes adverse effects, other beta-blockers may be tried, though they are generally less effective: 1, 2

• Nadolol: 40-320 mg daily
• Metoprolol: 25-100 mg extended release daily or twice daily
• Atenolol: limited evidence for moderate effect
• Timolol: 20-30 mg/day

Surgical Interventions for Medication-Refractory Tremor

Surgical therapies should be considered when medications fail due to lack of efficacy at maximum doses, dose-limiting side effects, or medical contraindications. 1

Treatment Algorithm for Surgical Candidates

For unilateral tremor or patients with medical comorbidities:

• Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy is preferred 1
• Shows sustained tremor improvement of 56% at 4 years 1
• Lowest complication rate: 4.4% compared to radiofrequency thalamotomy (11.8%) and DBS (21.1%) 1, 5
• 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

MRgFUS contraindications: 1, 5

• Cannot undergo MRI
• Skull density ratio <0.40
• Bilateral treatment needed
• Previous contralateral thalamotomy

For bilateral tremor or MRgFUS contraindications:

• Deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) of the thalamus 1, 6
• Provides adjustable, reversible tremor control that can be optimized over time 1
• Approximately 90% tremor control rate 2
• Preferred for younger patients as it offers long-term adjustability 1

Radiofrequency thalamotomy:

• Available but carries higher complication risks than MRgFUS 1
• Reserved for cases where DBS and MRgFUS are not feasible 1

Common Pitfalls to Avoid

• Do not prescribe beta-blockers without screening for contraindications - particularly important in elderly patients with cardiac or pulmonary comorbidities 7, 1
• Do not abandon primidone prematurely - allow 2-3 months for clinical benefit to manifest 1
• Do not use aspirin or other inadequate treatments - propranolol and primidone are the only evidence-based first-line options 1
• Do not delay surgical referral in severely disabled patients - surgical options provide superior tremor control (approximately 90%) compared to medications (approximately 50%) 2, 3
• Regular assessment of tremor severity and medication side effects is essential - dose adjustments may be needed based on clinical response and tolerability 1