Propranolol for Tremors in Spinocerebellar Ataxia Type 12: A Randomized Clinical Trial

BACKGROUND: Spinocerebellar ataxia type 12 (SCA12) is a neurodegenerative disorder with prominent upper limb tremors. No trials have evaluated tremor-targeted therapies in this population. OBJECTIVES: We evaluated long-acting propranolol for efficacy and safety in reducing tremors and improving ataxia and quality of life in SCA12. METHODS: In this single-center, randomized, double-blind, placebo-controlled trial, 60 genetically confirmed SCA12 patients (aged 18-65 years; TETRAS PS [The Essential Tremor Rating Assessment Scale Performance Subscale] upper limb component ≥2) were randomized 1:1 to receive extended-release propranolol or placebo. Propranolol was escalated by 40 mg/week (placebo by one tablet/week) up to 240 mg/day, limiting side effects or ≥30% reduction in TETRAS PS/ADL (Activities-of-Daily-Living Subscale) + PS. The stable dose was continued for 8 weeks (maintenance phase). Primary outcomes were changes from baseline in TETRAS PS and ADL + PS at maintenance weeks 4 and 8. Secondary outcomes included changes in the Scale for the Assessment and Rating of Ataxia (SARA), RAND 36-Item Short-Form Health Survey (SF-36) domains, and accelerometric tremor parameters. RESULTS: Propranolol significantly reduced TETRAS PS (LSM ± SE: -4.4 ± 0.3 at week 4; -4.42 ± 0.4 at week 8) and ADL + PS (-5.5 ± 0.63 at week 4; -5.56 ± 0.62 at week 8; P < 0.001 vs. placebo). Significant improvements were also noted in SARA and five of nine SF-36 domains at both time points. Accelerometry confirmed reductions in tremor peak frequency and power in all positions except rest. Fatigue and headache were the commonest adverse effects, with no discontinuations due to adverse events. CONCLUSION: Propranolol effectively reduced tremors and improved quality of life in SCA12, with good tolerability.