| 1. |
- Bastami, Salumeh, et al.
(author)
-
Influence of genetic polymorphism on tramadol pharmacokinetics and pharmacodynamics
-
Other publication (other academic/artistic)abstract
- Purpose: There is a significant interindividual variation in the response to tramadol (TRA), which can partly be explained by genetic variation. The main purpose of this study was to determine if there is a correlation between the metabolic ratio of O-desmethyltramadol (ODT) to TRA (MR) and time after drug administration. We also studied the association between genetic polymorphisms in CYP2D6, OPRM1 and ABCB1 and pharmacokinetic and pharmacodynamic properties of TRA.Methods: Nineteen healthy volunteers were randomized into two groups receiving a single dose of either 50 or 100 mg of orally administrated TRA. Blood samples were collected prior to dosing and up to 72 h after drug intake. The subjects were asked to report drug related symptoms (DRS) during the experimental day.Results: We found a positive correlation between MR and the time after drug intake for both intermediate metabolizers (IMs) and extensive metabolizers (EMs). For the only poor metabolizer (PM) with detectable ODT levels the MR was almost constant. The AUC MR and Cmax MR were associated with CYP2D6 genotype, showing the highest mean values for EMs. Multiple regression analysis showed that 56% of the variation in AUC MR could be explained by CYP2D6 alone and 78% by investigated SNPs altogether. There was great interindividual variation in DRS, but no associations could be found between DRS and investigated polymorphisms.Conclusions: MR can be used for estimation of the time of drug intake when the CYP2D6 genotype is known and taken into consideration. The influence of genetic polymorphisms in ABCB1 and OPRM1 requires further study. We propose that pharmacogenetics should be taken into consideration when interpreting clinical pharmacology and forensic toxicology results, more specifically CYP2D6 genotypes when interpreting the pharmacokinetics of TRA.
|
|
| 2. |
- Bastami, Salumeh, et al.
(author)
-
Pharmacogenetic aspects of tramadol pharmacokinetics and pharmacodynamics after a single oral dose
- 2014
-
In: Forensic Science International. - : Elsevier. - 0379-0738 .- 1872-6283. ; 238, s. 125-132
-
Journal article (peer-reviewed)abstract
- The major purpose of this study was to elucidate if genotyping can facilitate interpretations of tramadol (TRA) in forensic case work, with special regard to the estimation of the time of drug intake and drug related symptoms (DRS). The association between genetic polymorphisms in CYP2D6, OPRM1 and ABCB1 and pharmacokinetic and pharmacodynamic properties of TRA was studied. Nineteen healthy volunteers were randomized into two groups receiving a single dose of either 50 or 100 mg of orally administrated TRA. Blood samples were collected prior to dosing and up to 72 h after drug intake. The subjects were asked to report DRS during the experimental day. We found a positive correlation between the metabolic ratio of O-desmethyltramadol (ODT) to TRA and the time after drug intake for both CYP2D6 intermediate metabolizers and extensive metabolizers. For the only poor metabolizer with detectable ODT levels the metabolic ratio was almost constant. Significant associations were found between the area under the concentration-time curve (AUC) and three of the investigated ABCB1 single nucleotide polymorphisms for TRA, but not for ODT and only in the 50 mg dosage group. There was great interindividual variation in DRS, some subjects exhibited no symptoms at all whereas one subject both fainted and vomited after a single therapeutic dose. However, no associations could be found between DRS and investigated polymorphisms. We conclude that the metabolic ratio of ODT/TRA may be used for estimation of the time of drug intake, but only when the CYP2D6 genotype is known and taken into consideration. The influence of genetic polymorphisms in ABCB1 and OPRM1 requires further study.
|
|
| 3. |
- Haage, Pernilla, 1982-, et al.
(author)
-
Enantioselective pharmacokinetics of tramadol and its three main metabolites; impact of CYP2D6, CYP2B6, and CYP3A4 genotype
- 2018
-
In: Pharmacology Research & Perspectives. - : John Wiley & Sons. - 2052-1707. ; 6:4
-
Journal article (peer-reviewed)abstract
- Tramadol is a complex drug, being metabolized by polymorphic enzymes and administered as a racemate with the (+)- and (-)-enantiomers of the parent compound and metabolites showing different pharmacological effects. The study aimed to simultaneously determine the enantiomer concentrations of tramadol, O-desmethyltramadol, N-desmethyltramadol, and N,O-didesmethyltramadol following a single dose, and elucidate if enantioselective pharmacokinetics is associated with the time following drug intake and if interindividual differences may be genetically explained. Nineteen healthy volunteers were orally administered either 50 or 100 mg tramadol, whereupon blood samples were drawn at 17 occasions. Enantiomer concentrations in whole blood were measured by LC-MS/MS and the CYP2D6,CYP2B6 and CYP3A4 genotype were determined, using the xTAG CYP2D6 Kit, pyrosequencing and real-time PCR, respectively. A positive correlation between the (+)/(-)-enantiomer ratio and time following drug administration was shown for all four enantiomer pairs. The largest increase in enantiomer ratio was observed for N-desmethyltramadol in CYP2D6 extensive and intermediate metabolizers, rising from about two to almost seven during 24 hours following drug intake. CYP2D6 poor metabolizers showed metabolic profiles markedly different from the ones of intermediate and extensive metabolizers, with large area under the concentration curves (AUCs) of the N-desmethyltramadol enantiomers and low corresponding values of the O-desmethyltramadol and N,O-didesmethyltramadol enantiomers, especially of the (+)-enantiomers. Homozygosity of CYP2B6 *5 and *6 indicated a reduced enzyme function, although further studies are required to confirm it. In conclusion, the increase in enantiomer ratios over time might possibly be used to distinguish a recent tramadol intake from a past one. It also implies that, even though (+)-O-desmethyltramadol is regarded the enantiomer most potent in causing adverse effects, one should not investigate the (+)/(-)-enantiomer ratio of O-desmethyltramadol in relation to side effects without consideration for the time that has passed since drug intake.
|
|
| 4. |
- Haage, Pernilla, 1982-
(author)
-
Forensic Toxicological Aspects of Tramadol : Focus on Enantioselective Drug Disposition and Pharmacogenetics
- 2018
-
Doctoral thesis (other academic/artistic)abstract
- One of the most difficult parts in forensic toxicology is to interpret obtained drug concentrations. Was it therapeutic, toxic or even lethal to the particular individual that the blood sample was drawn from? Concentrations of opioid drugs are especially difficult to interpret, because of large interindividual differences in innate and acquired tolerance.Tramadol is a complex drug. Not only is it an opioid, it is also a racemic drug with the (+)- and (-)-enantiomers of the parent compound and metabolites showing different pharmacological effects. Further, it is metabolized by polymorphic enzymes, which may affect the amounts of metabolites formed and possibly the enantiomer ratios of the parent compound and its metabolites. It has been speculated that particularly the (+)/(-)-enantiomer ratio of O-desmethyltramadol is related to the risk of adverse effects, and it has been shown that the ratio is affected by CYP2D6 genotype.The overall aim of the thesis was to evaluate if forensic interpretations of tramadol, regarding toxicity and time since drug administration, may be improved by the use of genotyping and enantioselective concentration determination of tramadol and its three main metabolites.To simultaneously quantify the enantiomer concentrations of tramadol, Odesmethyltramadol, N-desmethyltramadol and N,O-didesmethyltramadol in whole blood, a liquid chromatography tandem mass spectrometry (LCMS/MS) method was developed and validated. Genetic variation in CYP2D6, CYP2B6, CYP3A4 (encoding the tramadol metabolizing enzymes), ABCB1 (encoding a transport protein) and OPRM1 (encoding the μ-opioid receptor) was investigated, using pyrosequencing, xTAG, and TaqMan analysis. The methods were applied to the blood samples of two study populations; 19 healthy volunteers administered a therapeutic, single tramadol dose, and 159 tramadol positive autopsy cases.The most important finding was the positive correlations between all four enantiomer ratios and time since tramadol administration in the healthy volunteers. All enantiomer ratios except the one of tramadol was also affected by the CYP2D6 genotype, which was apparent among the autopsy cases as well. Genetic variation in CYP2D6 and possibly CYP2B6 was shown to have an impact on tramadol pharmacokinetics, although no association to neither drug related symptoms nor tramadol related causes of death was found. Tramadol intoxications were predominantly characterized by low age (median 26 years) and male sex, often with a history of substance abuse and with other drugs (at fairly low concentrations) detected in blood.In conclusion, enantiomer concentration determination combined with genotyping seems promising regarding estimations of time since drug administration, although is of low value concerning interpretations of toxicity in autopsy cases.
|
|
| 5. |
- Haage, Pernilla, et al.
(author)
-
Quantitation of the enantiomers of tramadol and its three main metabolites in human whole blood using LC-MS/MS.
- 2016
-
In: Journal of Pharmaceutical and Biomedical Analysis. - : Elsevier BV. - 0731-7085 .- 1873-264X. ; 119, s. 1-9
-
Journal article (peer-reviewed)abstract
- The analgesic drug tramadol and its metabolites are chiral compounds, with the (+)- and (-)-enantiomers showing different pharmacological and toxicological effects. This novel enantioselective method, based on LC-MS/MS in reversed phase mode, enabled measurement of the parent compound and its three main metabolites O-desmethyltramadol, N-desmethyltramadol and N,O-didesmethyltramadol simultaneously. Whole blood samples of 0.5g were fortified with internal standards (tramadol-(13)C-D3 and O-desmethyl-cis-tramadol-D6) and extracted under basic conditions (pH 11) by liquid-liquid extraction. Chromatography was performed on a chiral alpha-1-acid glycoprotein (AGP) column preceded by an AGP guard column. The mobile phase consisted of 0.8% acetonitrile and 99.2% ammonium acetate (20mM, pH 7.2). A post-column infusion with 0.05% formic acid in acetonitrile was used to enhance sensitivity. Quantitation as well as enantiomeric ratio measurements were covered by quality controls. Validation parameters for all eight enantiomers included selectivity (high), matrix effects (no ion suppression/enhancement), calibration model (linear, weight 1/X(2), in the range of 0.25-250ng/g), limit of quantitation (0.125-0.50ng/g), repeatability (2-6%) and intermediate precision (2-7%), accuracy (83-114%), dilution integrity (98-115%), carry over (not exceeding 0.07%) and stability (stable in blood and extract). The method was applied to blood samples from a healthy volunteer administrated a single 100mg dose and to a case sample concerning an impaired driver, which confirmed its applicability in human pharmacokinetic studies as well as in toxicological and forensic investigations.
|
|
| 6. |
- Johansen, Sys Stybe, et al.
(author)
-
Temporal patterns of tramadol in hair after a single dose
- 2020
-
In: Forensic Science International. - : ELSEVIER IRELAND LTD. - 0379-0738 .- 1872-6283. ; 316
-
Journal article (peer-reviewed)abstract
- This controlled study aimed to measure concentrations of tramadol (TRA) and its two main metabolites, N-desmethyltramadol (NDMT) and O-desmethyltramadol (ODMT), in hair following a single dose ingestion and to investigate the distribution patterns in hair by segmental analysis of hair samples taken at several sampling time points after ingestion. An oral dose (50 or 100 mg) of TRA was administered to 17 healthy volunteers. Hair samples were collected prior to drug administration and 14, 30, 60 and 120 days after ingestion. Each sample was segmented in 5 mm segments and washed. The analytes were extracted from pulverized hair by incubation in extraction media for 18 h at 37 degrees C. A validated UHPLC-MS/MS method was used to quantify the analytes at a LLOQ of 0.001 ng/mg. Hair segments corresponding to the time of ingestion were positive for TRA and the metabolites of each sampling time point, although neighboring segments also showed positive results. The highest concentrations for both dosage groups were observed in the proximal segment of hair collected 14 days after ingestion for all subjects: 0.061-0.95 ng TRA/mg, 0.012-0.86 ng NDMT/mg and 0.009-0.17 ng ODMT/mg (n = 16). Generally, the TRA concentration was higher than the metabolites concentrations but depended on the CYP2D6 phenotype. The metabolite to TRA ratios were stable within a subject over the sampling time points, however it varied greatly between subjects. No significant differences in hair concentrations were found between the two dosage groups at each sampling time. Several confounding factors were identified such as hair pigmentation and internal sweat. We showed that analysis of 5 mm segments improved the determination of the exposure time after a single ingestion of TRA. In addition, in the later sampling time points the analytes were spread more between segments and the total drug amount of each later sampling time point declined up to a 100% (median: 75%) due to wash out. The presented results are important additions to the sparse literature reporting single dose of psychoactive drugs in hair. (C) 2020 Elsevier B.V. All rights reserved.
|
|
