L Färber

Charité Universitätsmedizin Berlin, Berlin, Land Berlin, Germany

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Publications (82)177.72 Total impact

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    ABSTRACT: In 2 crossover studies, 12 healthy volunteers (6 male/6 female) received a single oral dose of mycophenolate mofetil (MMF) 1000 mg or an equimolar dose of enteric-coated mycophenolate sodium (EC-MPS) 720 mg fasting with and without coadministered omeprazole 20 mg bid. The plasma concentrations of mycophenolic acid (MPA) and of the inactive metabolite mycophenolic acid glucuronide (MPA-G) were measured by high-performance liquid chromatography (HPLC). In addition, dissolution of MMF 500 mg or EC-MPS 360 mg tablets was determined using an USP paddle apparatus in aqueous buffer of pH 1 to 7. The bioavailability of MPA following administration of MMF or EC-MPS was similar except for the time to peak concentration, which was longer in the EC-MPS group. Concomitant treatment with omeprazole lowered significantly C(max) and AUC(12h) of MPA following administration of MMF. The pharmacokinetics of EC-MPS was not affected. Dissolution of MMF in aqueous buffer decreased dramatically at pH above 4.5. The EC-MPS tablet was stable up to pH 5. Above, EC-MPS was quantitatively disintegrated and MPS quantitatively dissolved. There is strong evidence that impaired absorption of MMF with concomitant proton pump inhibitors is due to incomplete dissolution of MMF in the stomach at elevated pH.
    The Journal of Clinical Pharmacology 09/2011; 52(8):1265-72. · 2.84 Impact Factor
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    ABSTRACT: Objective: As in a prospective, randomized, placebo-controlled, multicenter, double-blind trial in fibromyalgia [FMS] a significant reduction of pain especially, but of other symptoms as well, could be gained after 10 days of peroral daily treatment with 5 mg tropisetron, the question was evaluated as to whether quicker and better effects could be achieved with intravenous application of 2 mg tropisetron daily for a limited period of time. Methods: In the first cohort, 18 FMS patients received a single bolus intravenous [i.v.] injection of 2 mg tropisetron, in the second cohort 24 FMS patients were treated with 2 mg i.v. bolus injection tropisetron daily for five days. Pain intensity was measured with the visual analog scale and the painscore; pain at the tenderpoints and control points [dolorimeter] was evaluated as well as 17 ancillary symptoms before and after treatment; furthermore, pain intensity was followed up by means of a patient diary, until pain recurrence. Results: Even with a single i.v. injection of 2 mg tropisetron a significant pain reduction as well as an enhancement of the pain threshold provable by dolorimetry could be achieved; however, this lasted only a few days. Three out of these 18 patients did not respond at all to therapy. If 2 mg tropisetron were applied daily for five days, 23 of 24 patients showed a pain reduction, which lasted for two weeks to two months in 20 of these patients. Two patients stopped fillling in the pain diary. Twelve ancillary symptoms such as sleep disturbances, fatigue, morning stiffness, and others, were also significantly improved by the latter treatment. In the global assessment 16 out of 24 patients showed a significant improvement and seven showed a slight improvement of their disease. There was only one patient who did not experience any improvement. Tolerability was good. Conclusion: Intravenous injection of 2 mg of the 5-HT3 receptor antagonist tropisetron once daily for five days can often produce a longer-lasting therapeutic effect on fibromyalgia symptoms. The results achieved are now being evaluated in a randomized, placebo-controlled, double-blind trial.
    01/2010; 8(4):31-40.
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    ABSTRACT: The influence of pantoprazole 40 mg twice daily on the bioavailability of a single dose of mycophenolate mofetil 1000 mg or enteric-coated mycophenolate sodium is investigated in healthy volunteers. The plasma concentrations of mycophenolic acid and of the inactive metabolite mycophenolic acid glucuronide are measured by high-performance liquid chromatography. The pharmacokinetic parameters following sole administration are similar for mycophenolate mofetil and enteric-coated mycophenolate sodium except for the time to peak concentration, which is longer in the enteric-coated mycophenolate sodium group. Concomitant treatment with pantoprazole significantly (P < .001) lowers the mycophenolic acid exposure following administration of mycophenolate mofetil. The peak concentrations drop by 57%, and area under the curve decreases from 0 to 12 hours by 27%. In contrast, pantoprazole does not change the pharmacokinetics of enteric-coated mycophenolate sodium. Given that mycophenolic acid exposure correlates with the incidence of biopsy-proven acute rejections in renal transplant recipients, these findings may have clinical implications. Administration of pantoprazole in combination with mycophenolate mofetil could possibly result in an insufficient mycophenolic acid exposure, increasing the risk of treatment failure.
    The Journal of Clinical Pharmacology 10/2009; 49(10):1196-201. · 2.84 Impact Factor
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    ABSTRACT: In two crossover studies with 12 (6 males/6 females) healthy young volunteers each, we compared the bioavailability of Neoimmun capsules with the microemulsion Neoral and the influence of a fat-rich breakfast on the bioavailability of Neoimmun. Each volunteer received a single dose of 200 mg cyclosporine A in each period. Blood samples were taken up to 24 h and analysed for cyclosporine A by high-performance liquid chromatography (HPLC) and photometric detection. The pharmacokinetic parameters were determined by non-compartmental analysis. The treatments were tested for bioequivalence and significant differences. The bioavailability of Neoimmun was significantly lower compared to Neoral, albeit Neoimmun met the bioequivalence criterion (90% confidence interval of AUC 0.80-0.94) or missed the criterion only marginally (90% confidence interval of c (max) 0.75-0.91). The bioavailability of Neoimmun as determined by area under the blood concentration-time curve (AUC) increased by nearly 20% after a fat-rich breakfast. However, mean peak concentrations after food were only higher in male subjects, whereas mean peak concentrations in female subjects were lower compared to fasting administration. In conclusion, our data show that Neoimmun exhibits a lower bioavailability than the microemulsion Neoral and that food has a significant but variable and sex-dependent impact on the bioavailability of Neoimmun capsules.
    Archiv für Experimentelle Pathologie und Pharmakologie 09/2007; 375(6):393-9. · 2.15 Impact Factor
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    ABSTRACT: The 5-HT3 receptor is a pentameric ligand-gated cation channel which is found in the central and peripheral nervous system and on extraneuronal locations like lymphocytes, monocytes and fetal tissue. Five monomer subtypes, the 5-HT(3A-E) subunits, have been identified which show differences in the amino-terminal and the transmembrane region. The functional relevance of different receptor compositions is not yet clarified. 5-HT3 receptors are located predominantly in CNS regions that are involved in the integration of the vomiting reflex, pain processing, the reward system and anxiety control. The preferential localization on nerve endings is consistent with a physiological role of 5-HT3 receptors in the control of neurotransmitter release such as dopamine, cholecystokinin, glutamate, acetylcholine, GABA, substance P, or serotonin itself. 5-HT3-receptor agonists cause unpleasant effects like nausea and anxiety, and no clinical use has been considered. In contrast, the introduction of 5-HT3-receptor antagonists for chemotherapy-induced vomiting was extremely successful. After development of other gastrointestinal indications like postoperative vomiting and diarrhea-predominant irritable bowel syndrome recent research focuses on rheumatological indications such as fibromyalgia, rheumatoid arthritis and tendinopathies. Positive effects have also been observed for pain syndromes such as chronic neuropathic pain and migraine. These effects seem to be related to substance P-mediated inflammation and hyperalgesia. Furthermore, antiinflammatory and immunomodulatory properties have been observed for 5-HT3-receptor antagonists which might explain promising findings in systemic sclerosis and other immunological conditions. For all of these innovative indications the optimal dosing schedule is a crucial issue, since a bell-shaped dose-response curve has been observed repeatedly for 5-HT3-receptor antagonists, particularly in CNS effects.
    European Journal of Pharmacology 04/2007; 560(1):1-8. · 2.59 Impact Factor
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    ABSTRACT: Background The immunosuppressant cyclosporin A has been used with success in the treatment of chronic plaque-type psoriasis; little is known about its effect on palmoplantar psoriasis.Subjects and methods Thirty-three patients (12 women, 21 men; mean age = 44.2 years, range 22-68 years) with palmoplantar psoriasis were treated with oral cyclosporin A, (CyA), 2.5 mg/kg/day, which could be increased to 5 mg/kg/day, for 12 weeks. Patients were followed up for a further 4 weeks without CyA treatment. A total of 26 patients completed the 12-week treatment course, an additional six patients were followed up during 4 weeks after premature withdrawal. Efficacy was assessed by calculating the Psoriasis Area and Severity Index (PASl). a Local Psoriasis Severity Index (LPS1), and estimation of the area involved.Results Clinical response, being defined as at least 50% reduction of these parameters at the end of the therapeutic phase compared to baseline before treatment, was reached in 84% of the patients; 61% of the patients showed clinical response after only 6 weeks of treatment. No signs of severe hepatic or renal toxicity were noted during the study period; mild hypertension, which developed in one case, resolved after termination of the treatment. Relapses after treatment never reached the pretreatment baseline levels.Conclusions It is concluded that palmoplantar psoriasis can be treated effectively and safely with oral CyA at the low-dose range of 2.5-5 mg/kg/day. The results demonstrate the necessity for evaluation of a maintenance treatment in this special form of psoriasis, the doses and safety of which remain to be determined in future controlled clinical trials.
    Journal of the European Academy of Dermatology and Venereology 07/2006; 3(4):518 - 524. · 2.69 Impact Factor
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    ABSTRACT: The aim of this study was to compare the bioavailability of cyclosporine (CyA) from the generic dispersion formulation Cicloral (CIC) with the microemulsion formulation Neoral (NEO) and the original Sandimmune (SIM) capsules after single doses of 100, 300, or 600 mg of drug, respectively. The study was performed according to an open 3-period cross-over design with 12 young healthy male volunteers for each dosage. The concentrations of CyA and its main metabolites were determined by high performance liquid chromatography in whole blood and urine up to 48 hours postdosing. Peak concentrations and area under the time-concentration curve were greater for the NEO and CIC formulations compared with SIM, and the mean bioavailability of CIC was significantly (P<0.05) lower compared with NEO. The bioavailability of SIM compared with NEO was 54% to 71%, in agreement with previous results. Bioequivalence was not demonstrated between CIC (test) and NEO (reference) as the 90% confidence intervals were outside the 80% to 125% guidelines based on log-transformed AUCs, and were 75.2% to 87.7% at 100 mg, 79.2% to 91.8% at 300 mg, and 76.6% to 94.5% at 600 mg doses. The respective values for Cmax were 78.9% to 94.6%, 80.7% to 95.0%, and 71.4% to 84.1%. A good correlation was demonstrated between the urinary recovery of CyA and the AUC4. Therefore, the urinary recovery of CyA may be helpful as a surrogate parameter for the systemic exposure of patients to CyA. Whereas the relative amount of hydroxylated metabolites (AM1, AM9, AM1c) was similar for all formulations and doses, the urinary recovery of the N-demethylated metabolite AM4N decreased with increasing dose indicating saturable metabolism. No relationship could be demonstrated between CYP3A activity using dextromethorphan as a probe for the metabolic clearance of CyA.
    Therapeutic Drug Monitoring 06/2006; 28(3):312-20. · 2.23 Impact Factor
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    ABSTRACT: Tropisetron, an antagonist of serotonin type 3 receptor, has been investigated in chronic inflammatory joint process. Since T cells play a key role in the onset of several inflammatory diseases, we have evaluated the immunosuppressive activity of tropisetron in human T cells, discovering that this compound is a potent inhibitor of early and late events in TCR-mediated T cell activation. Moreover, we found that tropisetron specifically inhibited both IL-2 gene transcription and IL-2 synthesis in stimulated T cells. To further characterize the inhibitory mechanisms of tropisetron at the transcriptional level, we examined the DNA binding and transcriptional activities of NF-(kappa)B, NFAT and AP-1 transcription factors in Jurkat T cells. We found that tropisetron inhibited both the binding to DNA and the transcriptional activity of NFAT and AP-1. We also observed that tropisetron is a potent inhibitor of PMA plus ionomycin-induced NF-(kappa)B activation but in contrast TNF(alpha)-mediated NF-(kappa)B activation was not affected by this antagonist. Finally, overexpression of a constitutively active form of calcineurin indicated that this phosphatase may represent one of the main targets for the inhibitory activity of tropisetron. These findings provide new mechanistic insights into the anti-inflammatory activities of tropisetron, which are probably independent of serotonin receptor signalling and highlight their potential to design novel therapeutic strategies to manage inflammatory diseases.
    Biochemical Pharmacology 09/2005; 70(3):369-80. · 4.58 Impact Factor
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    ABSTRACT: When the microemulsion formulation of the critical dose drug cyclosporine A (CsA) (Sandimmun Optoral) was introduced in the mid-1990s, it became clear that this new formulation improves the oral bioavailability of CsA and has a positive influence on its pharmacokinetic variability. Previous studies with the original CsA formulation (Sandimmun) showed that the size of the emulsion droplets and concomitant food intake has an effect on the absorption of CsA from the small intestine when orally administered. It was suggested that these effects might have an influence on the drugs' pharmacokinetic parameters. In this study, we focused on the two above-mentioned aspects and compared the first and second generations of CsA products (Sandimmun, Sandimmun Optoral) to generic CsA formulations by analyzing the contents of cyclosporine A gel capsules with respect to their emulsion droplet and micelle sizes using photon correlation spectroscopy (PCS). We tried to discern any differences in droplet size between different generations of CsA formulations, primarily the second and third generation, through simple physical tests. Because a high fat content food may influence the absorption of CsA, we also determined the distribution of CsA between hydrophilic and lipophilic phases using high-performance liquid chromatography analysis. It became clear that when compared under simple physical conditions, established cyclosporine formulations and new generic products show significant differences in droplet size and distribution between an aqueous phase and a high fat content food. Whether these differences are of clinical relevance remains to be investigated.
    Drug Development and Industrial Pharmacy 06/2005; 31(4-5):357-66. · 1.54 Impact Factor
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    ABSTRACT: Previous studies evaluating the efficacy and tolerance of tropisetron for the treatment of fibromyalgia (FM) used the drug either intravenously or orally, and at different dosage levels ranging from 2 mg to 15 mg daily. The shortest treatment was a single dose and the longest treatment period covered 28 days. A significant reduction of the pain intensity was achieved by using tropisetron 5 mg per day. Apart from the fact that treatment periods were different, the efficacy of oral and intravenous administration did not differ significantly. Tropisetron was well tolerated; but in the 15 mg group in one of the studies, the decrease in pain was less than in the placebo group, however, the frequency of constipation and other gastrointestinal symptoms increased. Furthermore, it was hypothesized that due to the impacts of CYP2D6 activities, a daily dose of tropisetron 2 mg may be efficacious in slow metabolizers only. Although tropisetron proved to be efficacious in a group of fibromyalgia patients, the dose-response curves cannot yet be explained in a fully satisfactory manner, which may encourage research focusing on possible subgroups of FM.
    Scandinavian journal of rheumatology. Supplement 02/2004; 119:63-6.
  • R Kohnen, L Färber, M Späth
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    ABSTRACT: Vegetative and functional symptoms are, besides pain and tenderness of tender points, considered as additional information for the diagnosis of fibromyalgia (FM). In clinical trials, vegetative and functional symptoms have been included for selection of patients (e.g. sleep disturbances) and as secondary outcome parameters. Despite the relevance of these symptoms, no validated method is currently available but symptom lists are ad hoc developed by investigators. In this manuscript, data from a published double blind, randomised study are reanalysed which compared oral therapy over 10 days with 5 mg, 10 mg, and 15 mg to placebo in FM patients. This study applied a list of 17 vegetative and functional symptoms, which had to be scored by the patients by use of a 4-point severity scale (0 = none to 3 = severe). Factor analysis of the baseline data from 195 patients suggested to separate 6 sub-scales: Cardiovascular, gastrointestinal, psychiatric (sleep disturbance), nervous, autonomic system, and general disorders. Sleep disturbances, general symptoms (morning stiffness, fatigue) and autonomic symptoms (cold extremities, hyperhidrosis) were most severe in intensity. Analysis of sensitivity for treatment effects made use of differences between placebo and 5 mg tropisetron in changes between baseline and final assessment of the tropisetron trial. While, on the item level, differences in favour of tropisetron could only be demonstrated for sleep disorders, on the sub-scale level, also favourable effects of tropisetron could be shown for cardiovascular and nervous system complaints and, as a tendency, for general symptoms. On the other side, the sub-scale score of gastrointestinal symptoms worsened under tropisetron whilst it improved under placebo which effect was due to side effects of the active treatment. It is concluded that symptom clusters like sub-scales of a list of vegetative and functional symptoms will be more suitable for diagnostic purposes and evaluation of treatment outcome of clinical trials. Further research is urgently required which addresses the development of a FM-specific scale to assess vegetative and functional symptoms.
    Scandinavian journal of rheumatology. Supplement 02/2004; 119:67-71.
  • L Färber, U Haus, M Späth, S Drechsler
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    ABSTRACT: The 5-HT3 receptor is a ligand-gated cation channel located in the central and peripheral nervous system; it has also been detected on a variety of other cells. In the periphery, it is found on autonomic neurons and on neurons of the sensory and enteric nervous system. In the CNS, the 5-HT3 receptor has been localized in the area postrema, nucleus tractus solitarii, nucleus vaudatus, nucleus accumbens, amygdala, hippocampus, entorhinal, frontal, cingulate cortex, and in the dorsal horn ganglia. Further extraneuronal locations include among others lymphocytes, monocytes, and foetal tissue. 5-HT3 receptors modulate the release of neurotransmitters and neuropeptides like dopamine, cholecystokinin, acetylcholine, GABA, substance P, and serotonin itself. They have been demonstrated to be involved in sensory transmission, regulation of autonomic functions, integration of the vomiting reflex, pain processing and control of anxiety. While the physiologic functions of the 5-HT3 receptor are discrete and difficult to detect, it plays a key role in certain pathologic situations related to increased serotonin release. Clinical development of 5-HT3 receptor antagonists revealed a remarkable range of activities. 5-HT3 receptor antagonists do not modify any aspect of normal behaviour in animals or induce pronounced changes of physiological functions in healthy subjects. Clinical efficacy was shown for various forms of emesis like chemotherapy-induced, radiotherapy-induced, and postoperative emesis, diarrhoea-predominant irritable bowel syndrome, anxiety, chronic fatigue syndrome, alcohol abuse, and in pain syndromes such as fibromyalgia and migraine. Most recent data also suggest that 5-HT3 receptor antagonists are effective for the treatment of other rheumatic diseases such as rheumatoid arthritis, tendinopathies, periarthropathies, and myofascial pain. Other possible indications under discussion are chronic heart pain and bulimia. Unfortunately, experimental findings do not yet provide a homogenous conception of the significance of 5-HT3 receptors in all investigated fields; in nociception, for example, contradictory observations are still inadequately explained and complicated by bell-shaped dose-response curves. Further elucidation and better understanding of the serotonergic neuronal network remains a task for the next decade.
    Scandinavian journal of rheumatology. Supplement 02/2004; 119:2-8.
  • U Haus, M Späth, L Färber
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    ABSTRACT: Several 5-HT3 receptor antagonists are available (tropisetron, ondansetron, granisetron, dolasetron, and palonsetron), and further compounds are in clinical development. These substances show only minor differences in the activity profile regarding their affinity for particular receptors. 5-HT3 receptor antagonists are primarily used and found effective in the prevention and treatment of chemotherapy-induced nausea and emesis, and in postoperative nausea and vomiting (PONV). Antagonism of the 5-HT3 receptors in the peripheral and central nervous system is a probable mechanism of action. The substances are suitable as first-line therapy (combined with a corticosteroid) for the prevention of acute nausea and vomiting in patients treated with moderately to severely emetogenic chemotherapeutic agents. This combination is also moderately effective in the prevention of delayed nausea and vomiting. 5-HT3 receptor antagonists are an important constituent in the prevention and treatment of emesis and nausea caused by radiation therapy, especially in patients receiving whole body or upper abdominal treatment. Alosetron was found clinically effective in diarrhoea-predominant irritable bowel syndrome, whereas tropisetron in fibromyalgia and related pain disorders. Further indications for such treatment include anxiety disorders, alcohol dependence, drug withdrawal, and psychosis related to treatment of Parkinson's disease. 5-HT3 receptor antagonists are well tolerated with the most frequently reported adverse effects being headache, constipation, dizziness, tiredness, and gastrointestinal disturbances such as abdominal pain or constipation. Intravenous administration of serotonin induces the Bezold-Jarisch reflex and causes small reversible changes in electrocardiogram (ECG) parameters.
    Scandinavian journal of rheumatology. Supplement 02/2004; 119:12-8.
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    ABSTRACT: To determine the efficacy of a serotonin receptor (5-HT(3)) antagonist in the treatment of fibromyalgia (FM) in a prospective, randomized, double-blind, placebo-controlled, multicentre trial. Twenty-one female patients (age 21-63 years) with FM according to the American College of Rheumatology classification criteria for FM were assigned randomly to either a placebo group or to receive a daily intravenous bolus injection of 5 mg tropisetron for 5 days. In patients receiving tropisetron, the visual analogue scale (VAS) score for pain decreased by 28.9 compared with a decrease of 6.8 in the placebo group [probability (p)=0.063; effect size: 0.794]. Similar results were obtained using a body diagram pain score as a secondary efficacy parameter: mean pain reduction was 27.2 in the tropisetron group, versus 2.8 in the placebo group (p=0.038; effect size: 0.902). 5-HT(3) receptor antagonists provide significant pain relief for a group of FM patients.
    Scandinavian Journal of Rheumatology 02/2004; 33(4):267-70. · 2.22 Impact Factor
  • U Haus, M Späth, L Färber
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    ABSTRACT: Several 5‐HT3 receptor antagonists are available (tropisetron, ondansetron, granisetron, dolasetron, and palonsetron), and further compounds are in clinical development. These substances show only minor differences in the activity profile regarding their affinity for particular receptors. 5‐HT3 receptor antagonists are primarily used and found effective in the prevention and treatment of chemotherapy‐induced nausea and emesis, and in postoperative nausea and vomiting (PONV). Antagonism of the 5‐HT3 receptors in the peripheral and central nervous system is a probable mechanism of action. The substances are suitable as first‐line therapy (combined with a corticosteroid) for the prevention of acute nausea and vomiting in patients treated with moderately to severely emetogenic chemotherapeutic agents. This combination is also moderately effective in the prevention of delayed nausea and vomiting. 5‐HT3 receptor antagonists are an important constituent in the prevention and treatment of emesis and nausea caused by radiation therapy, especially in patients receiving whole body or upper abdominal treatment. Alosetron was found clinically effective in diarrhoea‐predominant irritable bowel syndrome, whereas tropisetron in fibromyalgia and related pain disorders. Further indications for such treatment include anxiety disorders, alcohol dependence, drug withdrawal, and psychosis related to treatment of Parkinson's disease. 5‐HT3 receptor antagonists are well tolerated with the most frequently reported adverse effects being headache, constipation, dizziness, tiredness, and gastrointestinal disturbances such as abdominal pain or constipation. Intravenous administration of serotonin induces the Bezold‐Jarisch reflex and causes small reversible changes in electrocardiogram (ECG) parameters.
    Scandinavian Journal of Rheumatology - SCAND J RHEUMATOL. 01/2004; 33:12-18.
  • L Färber, U Haus, M Späth, S Drechsler
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    ABSTRACT: The 5‐HT3 receptor is a ligand‐gated cation channel located in the central and peripheral nervous system; it has also been detected on a variety of other cells. In the periphery, it is found on autonomic neurons and on neurons of the sensory and enteric nervous system. In the CNS, the 5‐HT3 receptor has been localized in the area postrema, nucleus tractus solitarii, nucleus vaudatus, nucleus accumbens, amygdala, hippocampus, entorhinal, frontal, cingulate cortex, and in the dorsal horn ganglia. Further extraneuronal locations include among others lymphocytes, monocytes, and foetal tissue. 5‐HT3 receptors modulate the release of neurotransmitters and neuropeptides like dopamine, cholecystokinin, acetylcholine, GABA, substance P, and serotonin itself. They have been demonstrated to be involved in sensory transmission, regulation of autonomic functions, integration of the vomiting reflex, pain processing and control of anxiety. While the physiologic functions of the 5‐HT3 receptor are discrete and difficult to detect, it plays a key role in certain pathologic situations related to increased serotonin release. Clinical development of 5‐HT3 receptor antagonists revealed a remarkable range of activities. 5‐HT3 receptor antagonists do not modify any aspect of normal behaviour in animals or induce pronounced changes of physiological functions in healthy subjects. Clinical efficacy was shown for various forms of emesis like chemotherapy‐induced, radiotherapy‐induced, and postoperative emesis, diarrhoea‐predominant irritable bowel syndrome, anxiety, chronic fatigue syndrome, alcohol abuse, and in pain syndromes such as fibromyalgia and migraine. Most recent data also suggest that 5‐HT3 receptor antagonists are effective for the treatment of other rheumatic diseases such as rheumatoid arthritis, tendinopathies, periarthropathies, and myofascial pain. Other possible indications under discussion are chronic heart pain and bulimia. Unfortunately, experimental findings do not yet provide a homogenous conception of the significance of 5‐HT3 receptors in all investigated fields; in nociception, for example, contradictory observations are still inadequately explained and complicated by bell‐shaped dose‐response curves. Further elucidation and better understanding of the serotonergic neuronal network remains a task for the next decade.
    Scandinavian Journal of Rheumatology - SCAND J RHEUMATOL. 01/2004; 33:2-8.
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    ABSTRACT: Paclitaxel concentrations in the brain are very low after intravenous injection. Since paclitaxel is excluded from some tumors by p-glycoprotein (p-gp), the same mechanism may prevent entry into the brain. In vitro, paclitaxel transport was examined in capillaries from rat brains by confocal microscopy using BODIPY Fl-paclitaxel. Western blots and immunostaining demonstrated apical expression of p-gp in isolated endothelial cells, vessels, and tissue. Secretion of BODIPY Fl-paclitaxel into capillary lumens was specific and energy-dependent. Steady state luminal fluorescence significantly exceeded cellular fluorescence and was reduced by NaCN, paclitaxel, and SDZ PSC-833 (valspodar), a p-gp blocker. Leukotriene C(4) (LTC(4)), an Mrp2-substrate, had no effect. Luminal accumulation of NBDL-cyclosporin, a p-gp substrate, was inhibited by paclitaxel. In vivo, paclitaxel levels in the brain, liver, kidney, and plasma of nude mice were determined after intravenous injection. Co-administration of valspodar led to increased paclitaxel levels in brains compared to monotherapy. Therapeutic relevance was proven for nude mice with implanted intracerebral human U-118 MG glioblastoma. Whereas paclitaxel did not affect tumor volume, co-administration of paclitaxel (intravenous) and PSC833 (peroral) reduced tumor volume by 90%. Thus, p-gp is an important obstacle preventing paclitaxel entry into the brain, and inhibition of this transporter allows the drug to reach sensitive tumors within the CNS.
    Journal of Clinical Investigation 12/2002; 110(9):1309-18. · 12.81 Impact Factor
  • T h Stratz, L Färber, W Müller
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    ABSTRACT: To determine whether local injection of the 5-HT3-receptor antagonist, tropisetron. reduces pain in tendinopathies to the same degree as a local injection of corticosteroids in combination with local anesthetic. Forty patients with tendinopathies were enrolled in this randomized, observer-blind study. An injection of either 5 mg tropisetron. or 10 mg dexamethasone combined with 60 mg lidocaine was administered around the affected tendon. The effect was measured with a visual analog pain scale before the injection, after 3 hours and on each of the following 7 days, in patients with good effects also 3 months after the injection. There were no significant differences between the tropisetron and the corticosteroid/anesthetic group in terms of pain at rest or on movement during the study. Both treatments were well tolerated. Local injection of tropisetron seems to be as safe and as effective as the combination of corticosteroids and local anesthetics in the treatment of painful tendinopathies.
    Scandinavian Journal of Rheumatology 02/2002; 31(6):366-70. · 2.22 Impact Factor
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    ABSTRACT: To establish the bioavailability of tropisetron (5 mg) administered orally as capsule compared with 2 mg given intravenously. Using a randomized crossover design, 18 healthy volunteers received a single oral dose of tropisetron (5 mg) and an intravenous bolus of tropisetron (2 mg) separated by a wash-out period of 1 week. Plasma concentrations of tropisetron were determined by h.p.l.c. and the pharmacokinetic parameters were estimated. The mean pharmacokinetic parameters for 5 mg tropisetron given orally were Cmax 3.46 ng ml(-1), t(max) 2.6 h, t(1/2) 5.7 h and AUC(0,infinity) 32.9 ng ml(-1) h. After intravenous administration initial plasma concentration was 15.1 ng ml(-1), t(1/2) 5.6 h, AUC(0,infinity) 20.7 ng ml(-1) h, V 678 l and CL 1800 ml min(-1). An inverse correlation was demonstrated between CYP2D6 activity, measured by the sparteine metabolic ratio, and the bioavailability (mean 0.60, range 0.27-0.99) of oral tropisetron. Tropisetron exhibits a wide range of oral bioavailability at therapeutic doses, which is mainly determined by CYP2D6 activity.
    British Journal of Clinical Pharmacology 01/2002; 52(6):705-7. · 3.58 Impact Factor
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    ABSTRACT: A prospective, randomized, placebo-controlled, multicenter, double-blind trial in fibromyalgia patients demonstrated that peroral daily treatment with 5 mg tropisetron for 10 days produced a significant reduction in pain and other symptoms. The aim of the present study was to determine whether intravenous administration of 2 mg tropisetron daily for a limited period of time would produce quicker and more favorable results. In the first cohort 18 fibromyalgia patients received a single intravenous injection of 2 mg tropisetron. In the second cohort 24 fibromyalgia patients were treated with 2 mg intravenous tropisetron daily for 5 days. Pain intensity was measured with the visual analog scale and the pain score. Pain at tender and control points (dolorimeter) as well as 17 ancillary symptoms before and after treatment were evaluated. Pain intensity was followed-up by means of a patient diary until recurrence. Dolorimetry revealed that a single intravenous injection of 2 mg tropisetron significantly reduced pain and enhanced pain threshold. These effects, however, lasted for only a few days. Of 18 patients in the first cohort, only three showed no response to therapy. Of the 24 patients in the second cohort, 23 showed pain reduction when 2 mg tropisetron was administered daily for 5 days. Pain relief lasted for 2 weeks to 2 months in 20 of these patients. Two patients stopped filling in the pain diary. Twelve ancillary symptoms such as sleep disturbances, fatigue, morning stiffness were also significantly improved by the latter treatment. In the global assessment 16 out of 24 patients showed significant improvement and seven showed slight improvement. Only one patient experienced no improvement. Tolerability was good. In conclusion, intravenous injection of 2 mg of the 5-hydroxytryptamine3 receptor antagonist tropisetron once daily for 5 days produced a longer-lasting therapeutic effect on fibromyalgia symptoms than did peroral daily treatment with 5 mg of this drug. The results achieved are currently being evaluated in a randomized, placebo-controlled, double-blind trial.
    Drugs under experimental and clinical research 02/2001; 27(3):113-8.

Publication Stats

1k Citations
177.72 Total Impact Points

Institutions

  • 1995–2011
    • Charité Universitätsmedizin Berlin
      • Department of Anesthesiology and Operative Intensive Care Medicine
      Berlin, Land Berlin, Germany
  • 2001–2009
    • Universität Regensburg
      • • Lehrstuhl für Pharmakologie und Toxikologie
      • • Institut für Pharmazie
      Regensburg, Bavaria, Germany
  • 2004
    • Novartis
      Bâle, Basel-City, Switzerland
  • 2000
    • Ludwig-Maximilian-University of Munich
      • Friedrich-Baur-Institute
      München, Bavaria, Germany
  • 1998
    • Johannes Gutenberg-Universität Mainz
      • III. Department of Medicine
      Mainz, Rhineland-Palatinate, Germany
  • 1996
    • Humboldt-Universität zu Berlin
      Berlín, Berlin, Germany
    • University of Cologne
      • Department of Dermatology and Venerology
      Köln, North Rhine-Westphalia, Germany
  • 1994–1996
    • Hannover Medical School
      • Department of Gastroenterology, Hepatology and Endocrinology
      Hannover, Lower Saxony, Germany
    • Freie Universität Berlin
      Berlín, Berlin, Germany
  • 1994–1995
    • Friedrich-Alexander Universität Erlangen-Nürnberg
      • Department of Neurology
      Erlangen, Bavaria, Germany