Linking Altered Central Pain Processing and Genetic Polymorphism to Drug Efficacy in Chronic Low Back Pain (Predictio) (Predictio)
Drug therapy in patients with chronic low back pain is a major challenge for physicians. One of the problems is the lacking knowledge in prediction of drug efficacy in a chosen patient. Usually one of the classes of pain medication is given to patients with a similar clinical picture, although different pain mechanisms may be responsible for this clinical picture.
Another reason for variable drug efficacy are genetic polymorphisms, this may be the reason why an unique drug produces different responses (from a lacking analgesic effect up to excessive effect or side-effects.
Quantitative sensory testing is a method that documents alterations in the pain perception system. Linking genetic polymorphisms to quantitative sensory testing may give us a tool for anticipation of drug efficacy.
Low Back Pain
Drug: Oxycodone 15mg
|Study Design:||Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Caregiver, Investigator)
Primary Purpose: Basic Science
|Official Title:||Linking Altered Central Pain Processing and Genetic Polymorphism to Drug Efficacy in Chronic Low Back Pain|
- Difference in NRS(pain scale) between measurement after and before drug administration [ Time Frame: 07/2012 ]
- Patients global impression of change scale after drug administration [ Time Frame: 07/2012 ]
- Pharmacogenetic variables(see before) [ Time Frame: 07/2012 ]
- Pharmacokinetics: measure of Imipramine and desipramine blood levels [ Time Frame: 07/2012 ]
- Reliability of repeated quantitative sensory testing in the same patient [ Time Frame: 12/2010 ]
|Study Start Date:||July 2010|
|Study Completion Date:||December 2015|
|Primary Completion Date:||April 2015 (Final data collection date for primary outcome measure)|
Active Comparator: 1
Drug: Oxycodone 15mg
15mg single administration p.o.
Active Comparator: 2
20mg single administration p.o.
Active Comparator: 3
75mg single administration p.o.
Placebo Comparator: 4
1 mg single administration p.o.
Drug therapy is an essential part of pain treatment. However, only a minor part of pain patients benefits from the available treatments or is able to tolerate the drugs. One important limitation of drug therapy is lack of instruments to predict their effect. Indeed, in clinical practice "classes" of drugs (e.g. antidepressants) are given to "classes" of patients (e.g. neuropathic pain patients). However, within those classes of patients very different pain mechanisms are likely to underlie the pain condition in different patients. If drugs affect part of these mechanisms, they will not work in all patients. Another reason for variability in drug responses is genetic variation leading to a spectrum of different responses to analgesics, from lack of efficacy to exaggerated responses, up to intolerable adverse effects.
Quantitative sensory testing comprises methods that document alterations and reorganization of the nociceptive system. Measuring an abnormal result in a chronic pain patient may provide us with the information that the underlying pain pathways somehow must be altered. An essential question is whether this information can be linked to drug efficacy in a mechanism-based treatment approach. A further important question is whether assessing genetic polymorphisms can explain different drug effects and hence help selecting the appropriate therapeutic strategy for individual patients.
We will test the hypothesis that there is a correlation between disturbances in specific pain mechanisms as assessed by quantitative sensory tests and analgesic efficacy after single-dose drug administration in patients with chronic low back pain. Genetic factors affecting drug metabolism and pain sensitivity will be analyzed as additional explanatory variables for drug efficacy.
Quantitative sensory testing: Heat pain threshold and tolerance, Ice water testing with central modulation of nociceptive input (DNIC), electrical pain detection and temporal summation (skin probe), pressure algometry with pain detection and threshold Drugs investigated: Imipramine, Oxycodone, Clobazam Blood samples: pharmacogenetics: Cytochrome variants CYP2D6, CYP2C19, CYP3A4, COMT haplotypes, CGH-1 variants, A118G of mu opioid receptor gene variants pharmacokinetics: kinetics of imipramine and desipramine
Please refer to this study by its ClinicalTrials.gov identifier: NCT01179828
|Dep. of Anesthesiolgy and Pain therapy, Bern University Hospital, Switzerland, 3010 Bern|
|Study Chair:||Michele Curatolo, Prof||University Hospital Bern, Switzerland|
|Study Director:||Andreas Siegenthaler, Dr Med||University Hospital Bern, Switzerland|
|Principal Investigator:||Pascal H Vuilleumier, Dr Med||University Hospital Bern, Switzerland|