Management of apixaban anticoagulation in a patient requiring therapeutic plasma exchange: a case report and a literature review.

Therapeutic plasma exchange (TPE) is used as an effective treatment modality for a variety of autoimmune disorders. Apart from its desired effect of removing pathological blood components, it also can remove coagulation factors and drugs. Currently, there is an insufficient amount of information regarding the use of direct oral anticoagulants in this setting. In this article, we present a case report of a patient with myasthenia gravis and chronic anticoagulation with apixaban who underwent a series of TPE while continuing apixaban treatment. We observed that only 10% of daily dose was removed by the procedure and plasma levels of apixaban corresponded with expected range. TPE was not associated with shortened drug plasma half-life. We did not observe any significant alteration of apixaban pharmacokinetics during the period of TPE therapy, as well as no thrombotic or bleeding events. This case report supports the use of apixaban in patients treated by TPE, nevertheless, to firmly establish apixaban efficacy and safety profile in this clinical setting further research is needed.

Pupillometry as an indicator of L-DOPA dosages in Parkinson's disease patients.

Dopamine was shown to induce mydriasis by excitation of alpha-adrenergic receptors at the dilator pupillae muscle. Pupilla diameter may thus serve as an indirect measure of peripheral pharmacokinetics of L-DOPA and dopamine. The aim of this study is to evaluate the effect of L-DOPA dosage on pupillometric parameters in Parkinson's disease (PD) patients. Sixteen PD patients and 14 healthy control subjects (CS) were studied. The statistical analysis revealed significant differences between CS and PD patients for the mean maximum and minimum pupil diameters (p = 0.017, p = 0.028, respectively), with higher values found in PD. Moreover, a significant dose-response relationship was found between the maximum pupil diameter and both the morning L-DOPA dose (R 2 = 0.78) and the total daily L-DOPA dose (R 2 = 0.93). A sigmoid-shaped curve best describes the dose-response relationship, with a ceiling effect at about 400 mg L-DOPA daily dose. In conclusion, measuring pupillometric parameters represents a sensitive tool for non-invasive evaluation of the peripheral effect of L-DOPA, especially with daily doses below 400 mg L-DOPA.

Correction to: Pupillometry as an indicator of L-DOPA dosages in Parkinson's disease patients.

Unfortunately, original article has been published without acknowledgement section.

Estimation of initial phenobarbital dosing in term neonates with moderate-to-severe hypoxic ischaemic encephalopathy following perinatal asphyxia.

WHAT IS KNOWN AND OBJECTIVE: Phenobarbital is the first-line treatment of seizures in asphyxiated neonates; however, due to the high pharmacokinetic variability in this population, there is no consensus on the optimal dosage regimen. This study was conducted to identify variables that affect phenobarbital fate during routine clinical care and then to evaluate the dosage schedule that could be applied in term asphyxiated neonates with respect to achieving the target therapeutic range. METHODS: Phenobarbital pharmacokinetics was calculated based on serum concentrations measurements using one-compartmental model. Body weight, body surface area, gestational age, creatinine clearance, total bilirubin, alanine aminotransferase, aspartate aminotransferase, international normalized ratio, Apgar scores, umbilical cord arterial pH and base excess were explored as covariates in linear regression models. Based on this analysis, phenobarbital loading and maintenance dose regimen were projected. RESULTS AND DISCUSSION: In the whole study population (N = 36), phenobarbital volume of distribution, clearance and half-life median (interquartile range) values were 0.49 (0.38-0.59) L/kg, 0.0045 (0.0034-0.0055) L/h/kg and 75.1 (60.2-103.3) hours, respectively. The drug volume of distribution was associated with body weight, length and body surface area, whereas clearance was not in relationship with any explored features. Weight-normalized loading dose of 15 mg/kg and weight-normalized daily maintenance dose of 3 mg/kg proved to be optimal in our study population to reach phenobarbital therapeutic range. WHAT IS NEW AND CONCLUSIONS: This study presents basis for phenobarbital initial dosing in term asphyxiated neonates during first week of life. Phenobarbital weight-normalized loading dose of 15 mg/kg lead to simulated target peak concentrations in 72% of neonates, weight-normalized maintenance dose of 3 mg/kg lead to steady state within therapeutic window in the same proportion of patients.

Pregnane xenobiotic receptors and their effect on drug elimination from the organism.

Nuclear receptors are intracellular proteins which, having been activated by their more or less specific ligands, regulate (usually increase) the transcription of target genes. They thus participate in a regulation of a number of physiologic functions. Some of them - especially pregnane xenobiotic receptors - serve primarily as protection of the organism from the xenobiotic intoxication. This is because many xenobiotics activate their function which consists in increasing the gene expression of enzymes involved in the metabolism of xenobiotics and detoxication drug transporters. Clarification of these mechanisms enabled the understanding of the substance of many drug-drug interactions observed in the clinical practice. Polymorphism of the nuclear receptors appears to be one of the causes of the interindividual variability in response to drug administration.

Impact of MDR1 genetic polymorphisms on postoperative piritramide analgesia.

OBJECTIVES: The aim of prospective study was to evaluate the therapeutic efficacy of piritramide in patients after removal of parathyroid glands in relation to MDR1 genotype. In the treatment of moderate acute postoperative pain, piritramide plays a major role. It is difficult to predict its optimal therapeutic efficacy and tolerability in individual patients. METHODS: We compared the effect of piritramide in 56 patients after surgical removal of parathyroid glands in a prospective study. We evaluated pain intensity, pain difference and sum of pain difference (SPID) using visual analogue scale (VAS in mm) and adverse effects in the relationship with the MDR1 - polymorphism of G2677T/A. RESULTS: In the wild-type group (2677GG), there was maximal pain difference of 30.6 ± 24.9 and SPID of 209.33 ± 95.80 while in genotype 2677TT and 2677GT, the corresponding values were 19.5 ± 25.5 and 147.07 ± 91.38, respectively. In group of patients with wild type of 2677GG genotype, there was 80 % of responders with more than 50 % reduction in VAS as compared to baseline while in group with carriers of 2677T allele, there are only 39 % of responders present (χ² = 5. 83; p = 0.016). Furthermore, the total consumption of piritramide was lower in comparison with the variant-allele carrying group (p = 0.008). The total incidence of adverse drug reactions was observed in 40 % of patients with wild type of 2677GG genotype when compared to 83% in the group carrying the variant allele (χ² = 7.92; p = 0.005). Significantly more patients in the wild-type group were satisfied with postoperative pain treatment in comparison to the variant allele group (χ² = 6. 49; p = 0.0109). CONCLUSION: We observed a better analgesic effect of piritramide and a decreased incidence of side effects in the wild-type genotype (2677GG) group, when compared with variant-allele carrying patients (Tab. 2, Fig. 1, Ref. 7).

Pharmacogenetics in clinical practice.

Pharmacogenetics is a discipline that investigates how genetic variation relates to the drug efficacy and safety. The goal of pharmacogenetics is a personalized treatment, where according to genotype we would be able to prescribe the most effective drug at the most appropriate dose for an individual patient. The aim of this review is to summarize pharmacogenetics as a specialization with its own background, research, methods, including barriers and promises for the future.

Tramadol efficacy in patients with postoperative pain in relation to CYP2D6 and MDR1 polymorphisms.

OBJECTIVES: The aim of our study was to evaluate impact of CYP2D6 and MDR1 polymorphisms on the analgesic efficacy of tramadol in patients after a knee arthroscopy. BACKGROUND: Pharmacokinetics of tramadol and its metabolites is stereoselective and displays high interindividual variability correlating with polymorphic CYP2D6 in the population. Available data provide controversial results regarding the analgesic efficacy of tramadol in subjects with different CYP2D6 genotypes. METHODS: Pain intensity was assessed using visual analogue scale at 2 and 24 hours after the knee arthroscopy in 156 patients. Polymorphisms CYP2D6*3,*4,*5,*6, and gene duplication and C3435T in MDR1 gene were analyzed by PCR - RFLP. RESULTS: Mean VAS2h value in the whole study group was 44.0 ± 16.5 mm. Mean pain difference, was lowest in the UM group and highest in the PM group. The pain difference varied significantly among the CYP2D6 subgroups (F = 4.29; p = 0.006) with significant differences between homEM vs hetEM, homEM vs PM, and UM vs PM subgroups. There were no significant differences among MDR1 subgroups with regards of pain difference. Mean tramadol consumption was 2.47 ± 1.17 mg/kg during the 24 h period. There were no significant differences in the drug consumption, reporting of adverse reactions, need for rescue analgesic medication or verbal description of pain among the CYP2D6 or MDR1 genotype subgroups. CONCLUSION: CYP2D6 plays a significant role in tramadol analgesic efficacy. The non-opioid analgesia in PMs was associated with better subjective pain relief in patients after a knee arthroscopy (Tab. 3, Ref. 18).

Edaravone attenuates disease severity of experimental auto-immune encephalomyelitis and increases gene expression of Nrf2 and HO-1.

The aim of this study was to evaluate therapeutic potential of edaravone in the murine model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE) and to expand the knowledge of its mechanism of action. Edaravone (6 mg/kg/day) was administered intraperitoneally from the onset of clinical symptoms until the end of the experiment (28 days). Disease progression was assessed daily using severity scores. At the peak of the disease, histological analyses, markers of oxidative stress (OS) and parameters of mitochondrial function in the brains and spinal cords (SC) of mice were determined. Gene expression of inducible nitric oxide synthase (iNOS), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1alpha was determined at the end of the experiment. Edaravone treatment ameliorated EAE severity and attenuated inflammation in the SC of the EAE mice, as verified by histological analysis. Moreover, edaravone treatment decreased OS, increased the gene expression of the Nrf2 and HO-1, increased the activity of the mitochondrial complex II/III, reduced the activity of the mitochondrial complex IV and preserved ATP production in the SC of the EAE mice. In conclusion, findings in this study provide additional evidence of edaravone potential for the treatment of multiple sclerosis and expand our knowledge of the mechanism of action of edaravone in the EAE model.

Pupillometry in healthy volunteers as a biomarker of tramadol efficacy.

WHAT IS KNOWN AND OBJECTIVE: The opioid effect of tramadol, which can be detected by pupillary response, is predominantly mediated by the O-demethylated metabolite, formed via CYP2D6. This study was designed to evaluate the effects of tramadol using different parameters of pupillometry as biomarkers. METHODS: Sixty-nine healthy volunteers received tramadol hydrochloride drops orally at a dose of 0·7 mg/kg. Pre-dose and 2-h post-dose pupillometric measurements were performed. The polymorphism of CYP2D6 was analysed. RESULTS AND DISCUSSION: Large interindividual variability was observed in the tramadol-induced pupillary reaction. Miosis was induced in 69·6% and mydriasis in 30·4% of the subjects. The pupillary response differed in relation to the CYP2D6 genotype. A maximal difference in initial pupil diameter of 0·81 mm was found in extensive metabolizers. There were significant effects observed on the pupillary light reflex parameters with tramadol administration (P < 0·05) except for the reflex amplitude and constriction velocity. WHAT IS NEW AND CONCLUSION: The pharmacodynamic effects of tramadol were easily detected using both static and dynamic pupil parameters. The pharmacodynamic profiles were markedly influenced by the CYP2D6 phenotype.

[Screening of benzodiazepines in urine by liquid chromatography with tandem mass spectrometric detection]. / Prukaz benzodiazepinu v moci pomocí kapalinové chromatografie s tandemovou hmotnostní detekci.

A sensitive and selective method for screening of benzodiazepines and their metabolites in urine using liquid chromatography coupled with tandem mass spectrometric detection is presented. Analytes were separated on C18 column using gradient elution. Ionisation of analytes was performed by positive electrospray operated in Selected Reaction Monitoring mode. Optimization of the chromatographic method, acid hydrolysis and liquid - liquid extraction was also described. The limit of detection for most of analytes was 1 ng/mL. The chromatograms of real samples, which are also presented, demonstrate the selectivity, universality and simplicity of the developed method.

The role of diclofenac and piritramide in the management of acute postoperative pain in hernioplasty.

OBJECTIVES: The aim of the study was to compare the effects of diclofenac and piritramide in acute postoperative pain after hernioplasty. BACKGROUND: In the treatment of moderate acute postoperative pain, non-steroidal anti-inflammatory drugs and opioids play the major role. The data on safety and effect of analgesia based on opioid and non-opioid drugs are still a controversial topic. METHODS: We compared the first-line treatment effects of diclofenac and piritramide in 105 patients after hernioplasty in a retrospective manner. The subsequent therapy combined piritramide with diclofenac. We evaluated the intensity of pain and its relief using a visual analogue scale (VAS). We also evaluated the necessity of application of other analgesics. RESULTS: One hour after the application of the first analgesic dose, we observed complete pain relief in 39.5% of patients treated with piritramide and in 19.4% of patients treated with diclofenac (chi2=5.17; p=0.02). After the use of piritramide, the pain relief (3.84 +/- 1.27 mm) was significantly higher than after diclofenac (3.34 +/- 0.77 mm). Another injection was needed in 76% and 54% of patients subjected to first-line treatment based on diclofenac and piritramide, respectively. CONCLUSION: We observed that the first-line analgesic treatment based on piritramide was more effective when compared to that based on diclofenac (Tab. 3, Ref. 3). Full Text in free PDF www.bmj.sk.

New insights in the mechanisms of impaired redox signaling and its interplay with inflammation and immunity in multiple sclerosis.

Multiple sclerosis (MS) is an autoimmune neurological disease characterized by chronic inflammation of the central nervous system (CNS), leading to demyelination and axonal damage and resulting in a range of physical, mental or even psychiatric symptoms. Key role of oxidative stress (OS) in the pathogenesis of MS has been suggested, as indicated by the biochemical analysis of cerebrospinal fluid and blood samples, tissue homogenates, and animal models of multiple sclerosis. OS causes demyelination and neurodegeneration directly, by oxidation of lipids, proteins and DNA but also indirectly, by inducing a dysregulation of the immunity and favoring the state of pro-inflammatory response. In this review, we discuss the interrelated mechanisms of the impaired redox signaling, of which the most important are inflammation-induced production of free radicals by activated immune cells and growth factors, release of iron from myelin sheath during demyelination and mitochondrial dysfunction and consequent energy failure and impaired oxidative phosphorylation. Review also provides an overview of the interplay between inflammation, immunity and OS in MS. Finally, this review also points out new potential targets in MS regarding attenuation of OS and inflammatory response in MS.

Epidural analgesia with sufentanil in relation to OPRM1 and ABCB1 polymorphisms.

The aim of this study was to evaluate the association between OPRM1 and ABCB1 polymorphisms on pain relief with epidural sufentanil in 69 patients after rectosigma resection for cancer. The median number of injections (SD) 2.31 (1.36), IQR=1, required by 118AA subjects was significantly lower in comparison with 118AG group 5.25 (3.13), IQR=6.5, (chi(2)=9.75, p=0.001); correspondingly median drug consumption of 1.16 (0.79), IQR=1.083, defined daily doses (DDD) was significantly less in the 118AA group in comparison with 2.14 (1.17), IQR=2.23, DDD in 118AG subjects, (chi(2)=7.00, p=0.008). Opioid-induced adverse effects were observed in 15 % and 33 % of patients in 118AA and 118AG groups, respectively (chi(2)=8.16, p=0.004). The median number of injections (SD) required by women and men was 3.30 (2.16), IQR=2, and 2.80 (1.59), IQR=1, respectively (chi(2)=6.25, p=0.012). Opioid-induced adverse effects were observed in 26 % and 12 % of women and men, respectively (chi(2)=5.49, p=0.011). Heterozygotes of OPRM1 polymorphism and women were more difficult to treat subpopulations that required higher doses of rescue analgesic medication and suffered more adverse effects.

Miotic action of tramadol is determined by CYP2D6 genotype.

Polymorphic CYP2D6 is the enzyme that activates the opioid analgesic tramadol by O-demethylation to its active metabolite O-demethyltramadol (M1). Our objective was to determine the opioid effects measured by pupillary response to tramadol of CYP2D6 genotyped volunteers in relation to the disposition of tramadol and M1 in plasma. Tramadol displayed phenotypic pharmacokinetics and it was possible to identify poor metabolizers (PM) with >99% confidence from the metabolic ratio (MR) in a single blood sample taken between 2.5 and 24 h post-dose. Homozygous extensive metabolizers (EM) differed from PM subjects by an almost threefold greater (P=0.0014) maximal pupillary constriction (Emax). Significant correlations between the AUC and Cmax values of M1 versus pupillary constriction were found. The corresponding correlations of pharmacokinetic parameters for tramadol itself were weaker and negative. The strongest correlations were for the single-point metabolic ratios at all sampling intervals versus the effects, with rs ranging from 0.85 to 0.89 (p<0.01). It is concluded that the concept of dual opioid/non-opioid action of the drug, though considerably stronger in EMs, is valid for both EM and PM subjects. This is the theoretical basis for the frequent use and satisfactory efficacy of tramadol in clinical practice when given to genetically non-selected population.

[Genotyping of CYP2D6 and CYP2C19]. / Genotypizace cytochromu P450 2D6 a 2C19.

BACKGROUND: Polymorphisms in drug metabolizing enzymes are considered as a major factor influencing the incidence of adverse drug reactions or failure of pharmacotherapy. Our aim was to compare the distribution of functional polymorphisms in the genes CYP2D6 and CYP2C19 between healthy control group and of patients reffered to our department due to adverse drug reactions or insufficient efficacy of a treatment. METHODS AND RESULTS: The group of patients comprised of 60 subjects, 218 healthy unrelated subjects were included in the cotrol group. In both groups genotypes of CYP2D6 and CYP2C19 were analyzed. There were significantly fewer extensive metabolizers of CYP2D6 in the patient group comparison with healthy control subjects (25.0% vs. 49.8%) while the proportion of intermediate metabolizers was significantly higher than in helthy population (58.3% vs. 38.5%). We also observed more poor metabolizers than in control group (13.3% vs. 6.8%), but the difference did not reach level of statistical significance probably due to low number of subjects. The distribution of either ultrarapid metabolizers of CYP2D6 or deficient alleles of CYP2C19 was similar in both groups. CONCLUSIONS: Clinically apparent alteration of drug effects are often caused by partial or complete deficit of CYP2D6 activity. Our results confirm the importance of CYP2D6 polymorphisms on the efficycy and safety of pharmacotherapy.

Efficacy and safety of human mesenchymal stromal cells in healing of critical-size bone defects in immunodeficient rats.

To evaluate the preclinical efficacy and safety of human mesenchymal stem cells (hMSC) rapidly expanded in growth medium for clinical use with human serum and recombinant growth factors, we conducted a controlled, randomized trial of plasma clots with hMSC vs. plasma clots only in critical segmental femoral defects in rnu/rnu immunodeficient rats. X-ray, microCT and histomorphometrical evaluation were performed at 8 and 16 weeks. MSC were obtained from healthy volunteers and patients with lymphoid malignancy. Human MSC survived in the defect for the entire duration of the trial. MSC from healthy volunteers, in contrast to hMSC from cancer patients, significantly improved bone healing at 8, but not 16 weeks. However, at 16 weeks, hMSC significantly improved vasculogenesis in residual defect. We conclude that hMSC from healthy donors significantly contributed to the healing of bone defects at 8 weeks and to the vascularisation of residual connective tissue for up to 16 weeks. We found the administration of hMSC to be safe, as no adverse reaction to human cells at the site of implantation and no evidence of migration of hMSC to distant organs was detected.

Polymorphisms of the MDR1 gene in the Czech population.

There exists a marked inter-individual variability of P-glycoprotein expression and activity, which can be of clinical importance due to the large number of drugs that are substrates for the transporter. Previously identified polymorphisms in the MDR1 gene belong to important factors causing this phenomenon. Our aim was to investigate the frequency of major functional SNPs of the MDR1 gene coding for P-glycoprotein in the Czech population. DNA was isolated from whole blood of 189 healthy, young and unrelated subjects (99 females and 90 males, aged from 23 to 28 years). The genotypes of polymorphic positions C3435T, G2677T/A, C1236T and T-76A were determined by PCR-RFLP. Observed allelic frequencies were 56.5%, 46.0%, 0.53%, 44.5% and 37.6% for the alleles 3435T, 2677T, 2677A, 1236T and -76A, respectively. We have found 64 subjects homozygous for 3435T, 42 for 2677T, 40 for 1236T and 31 for -76A alleles. The allelic distribution complies well with Hardy-Weinberg equilibrium. Allelic frequencies of functionally important MDR1 variants are in the Czech population similar to that of other Caucasian populations.

Time trend analysis and variations in statins prescribing in the Czech Republic.

The aim of the study was to describe the effect of regulatory changes on the development of statins prescribing in individual districts of the Czech Republic. Retrospective analysis of reimbursed medical prescriptions for statins was based on the data from the General Health Care Insurance Company. The situation was assessed in 75 districts starting from the last quarter of 2001 and repeatedly every quarter up to the last quarter of the 2003. Anatomical Therapeutic Chemical Classification system (ATC) and Defined Daily Dose (DDD) as a unit of measurement were used. In the followed up time period the average consumption of statins in DDDs increased 2.12 times. Nearly tenfold variation across the regions in the number of DDDs per 1000 insured persons per day was found ranking from 4.53 to 46.48 in the last quarter of 2001, while corresponding values in 2003 were 6.10 and 37.55. The amount of DDDs was correlated with numbers of practising internist, general practitioners in individual districts in the same time periods. In the observed period opposite trend of the correlation coefficients was noted for internists and GPs. While the correlation of DDD/1000 persons/day to the number of internists decreased over time, the relation to the number of GPs gradually increased. Almost linear trend with gradual increase of the correlation coefficients between DDD/1000 persons/day and the number of insured persons was noted (T(t) = 0.659 + 0.009.t). Time trend analysis of statins utilization development could help to follow the effect of regulatory changes on its prescribing.

Genetic polymorphism of cytochrome P450 and methods for its determination.

The majority of human P450 dependent drug metabolism is carried out by polymorphic enzymes which can alter plasma concentration of the pharmacological active substance followed by an enhanced or suppressed pharmacological effect. The response of individual patients to drugs can be affected by variations in DNA sequence mainly by single nucleotide polymorphisms (SNPs). Knowledge of functionally important SNPs prior to the drug administrations may assist in the development of individualized pharmacotherapy avoiding unexpected drug responses, such as harmful adverse drug reactions or treatment failures. This review discusses both the basic characteristics of the major polymorphic cytochrome P450 enzymes and examines the pharmacogenetic methods employed to estimate metabolic status. We will focus mainly on the basic principles of genotyping assays involving molecular biology tools.