Propranolol for Parkinson's Disease Tremor
Propranolol can be used as adjuvant therapy specifically for tremor in Parkinson's disease, particularly resting and postural tremor, but it does not treat the underlying disease and should be avoided in older adults due to CNS side effects. 1
Evidence for Tremor Control
The strongest evidence comes from a 1987 double-blind crossover trial demonstrating that long-acting propranolol (160 mg/day) significantly reduced both resting tremor amplitude by 70% and postural tremor by 50% in parkinsonian patients, with most patients preferring to continue the medication. 1 This represents the highest quality data available for propranolol's efficacy in Parkinson's tremor, though the study was small (n=10). 1
Critical Age-Related Considerations
For patients 60 years and older with Parkinson's disease, propranolol should be avoided due to CNS effects including cognitive impairment, fatigue, and sleep disturbances. 2 The 1998 Neurology guidelines specifically recommend avoiding anticholinergics, amantadine, and selegiline in older patients due to CNS concerns—propranolol shares similar CNS liability with bradycardia, hypotension, fatigue, and sleep disturbances documented in 2-18.5% of patients. 3
When to Consider Propranolol
Use propranolol only in younger patients (under age 60) with Parkinson's disease when tremor is the predominant disabling symptom and standard antiparkinsonian medications have failed to control it adequately. 2, 1
- Start with long-acting propranolol 160 mg daily as adjuvant therapy to existing antiparkinsonian medications. 1
- Target specifically resting and postural tremor components; kinetic tremor and dystonia respond poorly. 1
- Expect no improvement in other parkinsonian symptoms (bradykinesia, rigidity). 1
Important Safety Precautions
Screen for absolute contraindications before prescribing: 4
- AV block greater than first degree or SA node dysfunction (without pacemaker)
- Decompensated systolic heart failure
- Cardiogenic shock or severe hypotension
- Reactive airway disease or asthma
- Bradycardia
Monitor heart rate closely—one study reported substantial heart rate drops in 64% of patients (14/22), with one withdrawal due to heart rate falling to 56 bpm. 5 This high frequency of bradycardia raises particular concern in normotensive elderly patients. 5
Addressing the Reverse Causation Concern
A 2020 Lancet Neurology review raised concerns that propranolol use may be associated with increased Parkinson's disease risk, but this is likely explained by reverse causation: prodromal Parkinson's disease causes action tremor, which is treated with propranolol, creating a spurious association. 6 The estimated absolute risk would be only 1 case per 10,000 patients after 5 years of use—considered a very rare adverse effect. 6 This concern should not prevent appropriate use of propranolol for established Parkinson's tremor in younger patients. 6
Alternative Benefit: Dyskinesia Reduction
Propranolol at low doses may improve levodopa-induced ballistic and choreic dyskinesia by approximately 40% without worsening parkinsonian motor disability. 7 This represents an additional potential indication beyond tremor control, though dystonic dyskinesia does not respond. 7
Limitations of Evidence
A 2003 Cochrane review found insufficient evidence to definitively establish efficacy and safety due to methodological limitations in available trials (small sample sizes, lack of first-arm data in crossover studies). 5 However, the 1987 trial remains the best available evidence showing clinically meaningful tremor reduction with acceptable tolerability in carefully selected patients. 1
Discontinuation Protocol
Never abruptly stop propranolol after regular use. 3, 8 Taper gradually over 1-2 weeks by reducing the dose by 25% every 3-4 days to prevent rebound tachycardia, hypertension, and enhanced beta-adrenergic sensitivity. 8