Study process

A summary of the study process is outlined in Table ​Table1.1. The first screening visit will entail obtaining informed consent; reviewing patients’ medical history, including the patients’ current medications; performing sensory tests for mechanical sensitivity; collecting blood samples for liver and kidney function; and obtaining urine samples from pre-menopausal women for a pregnancy test. Patients will be provided with a pain diary to record their daily pain intensity for the 7 days that follow the screening visit. Patients with normal laboratory test results of liver and kidney function will be contacted over the phone. After the assessment of pain diaries for pain intensity, patients that meet the eligibility requirements of the study (see below) will be provided with study drugs according to the treatment regimen assigned for the first 2 weeks of the trial. Regular medications used before enrolment into the study will be continued.

Study process

Throughout each treatment period and during the washout, patients will be asked to record their average pain scores in a pain diary, once daily in the evening. At the beginning and end of each treatment block, sensory testing will be performed to determine the degree of dynamic mechanical allodynia and area of punctate hyperalgesia. At the end of each treatment block, patients will be asked to score the degree of their overall pain relief. Adverse events will also be captured at the end of each treatment block and after the washout week.