Protocol-required assessments performed at specified study visits include: collection of blood and urine for safety and efficacy testing; electrocardiogram (ECG); echocardiogram (echo); Quantitative Sensory Testing (pressure pain threshold via algometer, cutaneous mechanical pain via monofilament, and thermal testing via Q-Sense Small Fiber Test); transcranial Doppler (TCD); forearm blood flow measurement; skin blood flow measurement; and completion of quality of life questionnaires.