Clinical trial NCT00952159: CYTRAM (Cytochrome P450, Tramadol)
Official title: Validation of a New Method to Detect CYP2D6 Poor Metabolizers by Monitoring Seric Concentrations of O-demethyl-tramadol and Tramadol to Make a Ratio in Comparison With Genotyping in Post-operative Patients Treated With Intravenous Tramadol
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Post-operative Patients Treated by Tramadol
Keywords: tramadol
CYP2D6
O-demethyl-tramadol
poor metabolizer
genotyping
phenotyping
Lead sponsor: University Hospital, Caen
Sponsor class: OTHER
First posted: 2009-08-06
Enrollment: 301
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Post-operative patients treated by tramadol

Brief summary: Many methods to detect CYP2D6 poor metabolizers have been validated. Some of them are based on phenotyping (metabolism of dextromethorphan or debrisoquine) and some others on genotyping. Up to now, CYP2D6 pharmacogenetics has been restricted to the field of research, in spite of poor metabolizer profile concerns 5 to 10 % of caucasian population. Nevertheless, the polymorphism of CYP2D6 is responsible for the metabolism of many drugs, particularly of two opioids involved in pain management: codeine and tramadol, their metabolites representing the most effective part of the drug effect. So prescribing codeine or tramadol in a patient poor metabolizer for the CYP2D6 is likely to be ineffective in pain management.

O-demethyl-tramadol, the metabolite of tramadol via CYP2D6, is important to consider because its analgesic effect is 2 to 4 times more potent than tramadol.

The investigators propose to phenotype CYP2D6 in post-operative patients treated by tramadol by monitoring seric concentrations of O-demethyl tramadol and tramadol to make a ratio in comparison with genotype, and to find a threshold to determine poor metabolizers. As already described, genotyping CYP2D6 will use a rapid detection method of the alleles implicated in poor metabolizer status (CYP2D6\*3, \*4, \*5 et \*6) in a Caucasian population. Sampling will be executed at two times (H24 and H48 after surgery) and only with blood (three EDTA tubes) during the post-operative monitoring of the patients. This study is likely to include 320 post-operative patients treated with intravenous tramadol during one year in three university hospitals centers (CHU of Caen, Creteil and Rouen).

The first aim of this study is the validation of monitoring seric concentrations of O-demethyl-tramadol and tramadol to make the ratio in order to detect CYP2D6 poor metabolizers in therapeutic situation, comparing the result with genotyping. The finding of a poor metabolizer status in a patient will make the choice of analgesic drugs easier, avoiding tramadol and codeine. The final objective of this research is to be able to determine the CYP2D6 phenotype in a patient treated by tramadol without a good analgesia. By a single take of blood and a rapid response, this method should be liked to improve pain management. Furthermore, CYP2D6 phenotyping is interesting for the patient because many other drugs depend on this way of metabolism.


Eligibility criteria: Inclusion Criteria:

* age \> 18 years, post-operative patient treated with intravenous tramadol
* Caucasian origin
* take of blood at H24 and H48 in the post-operative monitoring

Exclusion Criteria:

* patient having already been included in the study
* patient taking opioid drugs before surgery
* patient taking one or more drugs inhibiting the CYP2D6 before or during surgery
* pregnancy or breast feeding patients having one or more contraindications for taking tramadol in post-operative analgesia
* hepatocellular incapacity (TP \< 70%)

Primary outcomes:
measure: To phenotype CYP2D6 in post-operative patients treated by tramadol by monitoring seric concentrations of O-demethyl tramadol and tramadol to make a ratio in comparison with genotype, and to find a threshold to determine poor metabolizers.
timeFrame: H24 and H48 after surgery
Secondary outcomes:
Other outcomes:
Locations:
city: Caen
country: France
facility: Private Clinic Saint-Martin
city: Caen
country: France
facility: Caen University Hospital
city: Créteil
country: France
facility: Créteil University Hospital
city: Rouen
country: France
facility: Rouen University Hospital
Study officials:
affiliation: University Hospital, Caen
name: Blandine de la Gastine, MD
role: PRINCIPAL_INVESTIGATOR
References: