The treatment of primidone for bulbar dysfunction in amyotrophic lateral sclerosis: a randomized, double-blind, cross-over controlled clinical trial

INTERVENTION: Group A:phase I: primidone 60 mg/d; Wash‐out period: no intervention; phase II: placebo control;Group B:phase I: placebo control; Wash‐out period: no intervention; phase II: primidone 60 mg/d; CONDITION: amyotrophic lateral sclerosis PRIMARY OUTCOME: Improvement rate of Center for Neurologic Study Bulbar Function Scale (CNS‐BFS) score; SECONDARY OUTCOME: Self‐rating dysphagia Scale;sub‐water test;The Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ‐40);Serum interleukin‐8 leve; INCLUSION CRITERIA: 1. Age >= 18 years; 2. Clinically positive, probable and probable ALS in accordance with the 1998 revised IEEscorial standards; 3. Medulla oblongata dysfunction (determined by the principal investigator through an interview); 4. CNS‐BFS score range is 50‐90 points; 5. Subjects who can take or receive oral medication; 6. Informed consent has been signed; 7. If patients are taking riluzole, they must have taken it at least 30 days before randomization; 8. Patients taking salivation medications, such as Nuedexta (DMQ), dextromethorphan, and quinidine, must have stopped taking them within 30 days prior to enrollment to be eligible for inclusion in the study.