A Clinical Study of Dihydroergotine Mesylate Extended-release Tablets for the Treatment of Drooling in Parkinson's Disease.

Inclusion Criteria: 1. Patients with Parkinson\'s disease diagnosed by the British Parkinson\'s Disease Brain Bank Diagnostic Criteria can come to the hospital accompanied by family members 2. drooling score using the Parkinson\'s Comprehensive Rating Scale (UPDRS) Part II (Item 6) ≥3; 3. MMSE ≥ 10 points (recording the patient\'s education level) 4. Adults over the age of 18 5. The applicant or his/her caregiver must be able to complete the record of the salivation score 6. Patients or family members voluntarily participate and sign an informed consent form. Exclusion Criteria: 1. Patients with non-primary Parkinson\'s disease 2. Known allergy to dihydroergotamine mesylate 3. Drug-induced hypersalivation, such as olanzapine, antipsychotics, clonazepam and other antiepileptic drugs, as well as direct and indirect cholinergic agonists for the treatment of Alzheimer\'s disease and myasthenia gravis 4. BoNT treatment for saliva within the previous 3 months 5. Patients with symptomatic bradycardia, severe orthostatic hypotension, symptomatic coronary insufficiency, severe organic cardiac damage, severe liver and kidney insufficiency: including ALT≥2.5ULN (upper limit of normal value of the executive laboratory); AST≥2.5ULN (upper limit of normal for the execution laboratory); Creatinine ≥ 1.5 ULN (upper limit of normal at the execution laboratory), active psychosis, pregnancy/pregnant woman