Outcome
Type |
Measure |
Description |
Time frame |
Safety issue |
Primary |
Pain intensity change between period 1 and 2 |
Pain intensity change between period 1 and 2, measured by numerical pain rating scale (NPRS) over one week (two evaluations per day, morning and evening) following the taking of paracetamol/ placebo. |
Day 1 to Day 7 (one week) and Day 15 to Day 21 (one week). |
|
Secondary |
Treatment responders at 30% (NPRS) |
Calculation of the decrease of NPRS by at least 30% between the beginning and the end of the treatment period (at least 30% difference between the average of four NPRS measurements over 2 days before the start of the treatment period and the average of the four NPRS measurements over 2 days at the end of the treatment period). The number of paracetamol responders will be compared to the number of placebo responders. |
During 2 days before period 1 (mean of Day -1 and Day 0) and at the end of period 1 (mean of Day 6 and Day 7); during 2 days before period 2 (mean of Day 13 and Day 14) and at the end of period 2 (mean of Day 20 and Day 21). |
|
Secondary |
Treatment responders at 50% (NPRS) |
Calculation of the decrease of NPRS by at least 50% between the beginning and the end of the treatment period (at least 50% difference between the average of four NPRS measurements over 2 days before the start of the treatment period and the average of four NPRS measurements over 2 days at the end of the treatment period). The number of paracetamol responders will be compared to the number of placebo responders. |
During 2 days before period 1 (mean of Day -1 and Day 0) and at the end of period 1 (mean of Day 6 and Day 7); during 2 days before period 2 (mean of Day 13 and Day 14) and at the end of period 2 (mean of Day 20 and Day 21). |
|
Secondary |
Number of paroxysms |
The number of paroxysms will be listed by the patient in the daily pain diary during all the study (28 days). |
Before period 1 (Day -6 to Day 0), over a week during period 1 (Day 1 to Day 7), over a week during wash-out (Day 8 to Day 14) and over a week during period 2 (Day 15 to Day 21). |
|
Secondary |
Paroxysms intensity (NPRS) |
The average pain of paroxyms will be evaluated by the patient in the daily pain diary during all the study (28 days). The pain intensity will be measured by NPRS: the scale ranges from 0 no pain to 10 maximal tolerable pain |
(Day -6 to Day 0), over a week during period 1 (Day 1 to Day 7), over a week during wash-out (Day 8 to Day 14) and over a week during period 2 (Day 15 to Day 21). |
|
Secondary |
Assessment of paracetamol (and placebo) consumption |
The number of paracetamol (and placebo) capsules intake will be listed by the patient in the pain diary during the 4 weeks of the study. |
At Day1, Day8, Day15, Day22 |
|
Secondary |
Assessment of dynamic mechanical allodynia |
Dynamic mechanical allodynia (DMA) will be evaluated by a standardized fine filament brush (Somedic, ~200-400mN) which will be moved laterally, slowly and without support, with a movement back and forth over an area of skin. Patients will be seated comfortably in a quiet room. This light touch will be applied 5 times. The sensation perceived by the patient, during each stimulus, will be rated using an ENV (0 - 10), where a score of 0 equals "no pain" and a score of 10 equals "pain maximum imaginable". The DMA will be quantified as the geometric mean of all scores corresponding to each stimulation |
At Day1, Day8, Day15, Day22 |
|
Secondary |
Assessment of liver and renal functions |
A tube will be taken for biochemistry analysis of alanine amino transferase, aspartate aminotransferase and bilirubin to assess the liver function and creatine level to assess the renal function at each visit. The assays will be carried out by the medical biochemistry laboratory of Clermont-Ferrand University Hospital. |
At Day-6, Day1, Day8, Day15, Day22 |
|
Secondary |
Blood dosage of glutathione |
In order to measure the plasma glutathione level, a blood sample will be taken at each visit. After centrifugation, an aliquot will be performed to recover the plasma. The tubes will be frozen at -80°C for subsequent dosage. |
At Day-6, Day1, Day8, Day15, Day22 |
|
Secondary |
Blood dosage of paracetamol and its metabolites |
In order to determine the plasma concentration of paracetamol and its metabolites, four blood samples will be taken at D1, D8, D15 and D22. After centrifugation, an aliquot will be performed to recover the plasma. The tubes will be frozen at -80°C for subsequent dosage. |
At Day1, Day8, Day15, Day22 |
|
Secondary |
Urinary dosage of paracetamol and its metabolites |
In order to determine the urinary concentration of paracetamol and its metabolites, four urine samples will be taken before and after each study period at D1, D7, D15 and D21 and will be frozen at -20°C for subsequent dosage. |
At Day1, Day7, Day15, Day21 |
|
Secondary |
Analysis of pharmacogenetics parameters |
Pharmacogenetics screening will focus on the metabolism of paracetamol and more specifically on the detection of the presence of one or more variant(s) of the genes UGT2B15, SULT1A1 and TRPV1. This screening will be performed on a single blood sample on D-6 (first visit). Two tubes will be taken and placed directly in the freezer at -80°C. This biological collection will be kept until the analysis. |
At the pre-selection visit (Day-6). |
|
Secondary |
Impact of paracetamol on patient feeling and satisfaction by Global Patient Impression of Change (PGIC) |
This scale is used to assess patient satisfaction with treatment by choosing an answer among 8 responses (ranging from "very strongly enhanced" to "very strongly improved") to reflect their overall health. |
At Day1, Day8, Day15, Day22 |
|
Secondary |
Impact of paracetamol on cognitive parameters evaluated by Cantab® tests: Motor Screening Test (MOT), Stocking of Cambridge (SOC), Information Sampling task (IST). |
The Cantab® test is a validated tool for exploring cognitive functions. It consists of a choice of tests that explore several cognitive dimensions: Planning (IST), Decision-making (SOC). The tests are done on a computer screen with a record of the score obtained for each test. The scores of the different tests are added and the total score compared between the 2 groups. Patients will be required to complete these tests once during their visits. |
At Day1, Day8, Day15, Day22 |
|
Secondary |
Emotional status by Hospital Anxiety and Depression scale (HAD) |
The Hospital Anxiety and Depression scale is a self-administered questionnaire in 14 items completed by the patient. It is used to determine the levels of anxiety and depression. Seven of the items relate to anxiety and seven relate to depression. Global score ranges from 0 to 42. |
At Day1, Day8, Day15, Day22 |
|
Secondary |
Sleep by the Pittsburgh Sleep Quality Index (PSQI) |
This questionnaire consists of 19 items and is used to measure sleep quality. It consists of 7 domains: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleep medication and daytime dysfunction. |
At Day1, Day8, Day15, Day22 |
|
Secondary |
Descriptive analysis of adverse event of paracetamol use. |
The adverse event will be reported by the patient on his pain diary during all the study. Furthermore, a daily phone-call will be performed by the team project during the two period of treatment |
Pain diary: over 4 weeks: At the pre-selection visit (Day -6) to the end of the study (Day 22). |
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