Efficacy of entacapone and pramipexole in treating non-motor symptoms of Parkinson’s disease: a prospective randomized controlled trial

Background and objective: Individuals with Parkinson’s disease exhibit a variety of non-motor symptoms that can negatively impact quality of life. Although both entacapone and pramipexole can be used to treat Parkinson’s disease via modulation of dopamine metabolism, the ways in which these treatments differ in terms of their effects on the non-motor symptoms of Parkinson’s disease are unknown. Participants and methods: This prospective, randomized, controlled trial will be conducted in the Geriatric Hospital of Hainan, Haikou, China. A total of 388 patients with idiopathic Parkinson’s disease will be randomly assigned to receive entacapone (n = 194) or pramipexole (n = 194). This study was approved by the Ethics Committee of the Geriatric Hospital of Hainan, China on August 30, 2013 (approval number: S2013-038-01) on August 30, 2013. Written informed consent regarding the study protocol and surgical procedure will be obtained from all participants. Results: The primary outcome measure will be the rate of improvement of non-motor symptoms 3 weeks after treatment. Secondary outcome measures will be soluble interleukin-2 receptor and homocysteine levels in serum, which reflect inflammation, and adverse events before and 3 weeks after treatment. Our self-controlled pilot study involving 100 patients showed that incidences of autonomic neurological symptoms such as postural hypotension, urinary urgency, urinary frequency, sexual dysfunction, dry mouth, and salivation, psychiatric symptoms such as cognitive dysfunction, hallucination, depression, and anxiety, and sensory abnormalities such as spasm, pain, and restless leg syndrome were remarkably reduced. Meanwhile, levels of serum soluble interleukin-2 receptor and homocysteine had noticeably decreased after treatment with entacapone and pramipexole. Conclusion: This trial will confirm the efficacy of entacapone and pramipexole in the treatment of non-motor symptoms of Parkinson’s disease. We hope that our findings will provide direction for future clinical treatment of non-motor symptoms of Parkinson’s disease, leading to improved patient quality of life. Trial registration: This study was registered with the Chinese Clinical Trial Registry on April 15, 2019 (registration number: ChiCTR1900022534). Protocol version is 1.0.