Patient description: The patient is a 55-year-old man who was recently diagnosed with Parkinson's disease. He is complaining of slowness of movement and tremors. His disease is ranked as mild, Hoehn-Yahr Stage I. His past medical history is significant for hypertension and hypercholesterolemia. He lives with his wife. They have three children. He used to be active with gardening before his diagnosis. He complains of shaking and slow movement. He had difficulty entering through a door, as he was frozen and needed guidance to step in. His handwriting is getting smaller. He is offered Levodopa and Trihexyphenidyl. He is an alert and cooperative man who does not have any signs of dementia. He does not smoke or use any illicit drugs.

Clinical trial eligibility criteria: eligible ages (years): 18.0-80.0,  Small Fiber Neuropathy Male and/or female subjects between the ages of 18 and 80 years. 2. Presence of a clinical diagnosis of Small Fiber Neuropathy (SFN), with at least 2 of the following clinical symptoms Burning feet Allodynia Diminished pain and/or temperature sensation Dry eyes or mouth Orthostatic dizziness Bowel disturbances (constipation, diarrhea, gastroparesis) Urinary disturbances Sweat changes (hyper-/hypohidrosis) Visual accommodation problems and/or blurred vision  Subjects with predominantly signs of large nerve fiber involvement, clinically significant abnormal nerve conduction studies. 2. History or presence of illnesses known to cause SFN (excluding diabetes mellitus). 3. Subjects with other severe pain conditions which may impair the self-assessment of pain due to SFN. 4. Any condition possibly affecting drug intake and absorption. 5. History of known alcohol, analgesic or illicit drug abuse within 12 months of Screening. 6. Subjects taking medications with activity at sodium channels. These medications are prohibited until the end of the study period and require a washout period of at least 5 half lives (90 days for capsaicin patches) prior to the Screening visit. 7. 12-lead ECG demonstrating QTcF (Fridericia's correction) >450 or a QRS interval >120 msec at Screening. If QTcF exceeds 450 msec, or QRS exceeds 120 msec, the ECG should be repeated two more times and the average of the three QTcF values should be used to determine the subject's eligibility. 8. Severe renal impairment (creatinine clearance ≤ 30 mL/min). 9. Treatment with an investigational drug within 30 days or 5 half-lives preceding the first dose of study medication. 10. Participation in other studies during the period of current study participation, or has planned surgery during the course of the study. 11. Pregnant females; breastfeeding females; females of childbearing potential not using effective contraception or not agreeing to continue effective contraception for at least 28 days after the last dose of investigational product. 12. Other clinically significant or unstable, or severe acute or chronic medical or psychiatric/psychological condition or laboratory abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the Investigator, would make the subject inappropriate for entry into this study. 13. In the case of incidental findings the patient and his/her treating physician will be informed and asked to undertake action if necessary. If a patient does not want to be informed about possible incidental findings, nor wants his treating physician to be informed, he or she cannot participate in this study