Search results for "PHARMACOKINETICS"
showing 10 items of 458 documents
Pharmacokinetics of dabigatran etexilate and rivaroxaban in patients with short bowel syndrome requiring parenteral nutrition: The PDER PAN study
2017
Background and aims: Patients on parenteral nutrition for short bowel syndrome (SBS) have a high risk of thrombotic complications and are often treated with parenteral anticoagulation. Direct oral anticoagulants are absorbed proximally in the digestive tract and may represent alternative regimens in selected SBS patients. In our pilot study, we provided pharmacokinetics parameters of dabigatran etexilate and rivaroxaban in this setting and compared peak (Cmax), trough (Ctrough) concentrations, and areas-under-the-concentration-time-curve (AUC(0) (-) (t)) to reference values retrieved from phase I-III studies. Methods: We enrolled 6 adults with a remaining small bowel length <= 200 cm, norma…
Melperone is an Inhibitor of the CYP2D6 Catalyzed O-demethylation of Venlafaxine
2003
INTRODUCTION Melperone, a butyrophenone neuroleptic, is frequently used for its sleep-inducing properties. Despite its common use for more than 30 years, it is not yet characterized regarding its effects on cytochrome P450 s (CYPs). In an open pilot study, effects of melperone on the steady-state blood levels of venlafaxine, a recently introduced serotonin- and noradrenaline reuptake inhibiting antidepressant, were assessed. METHODS The dose-corrected serum concentrations of venlafaxine and O-desmethylvenlafaxine were analyzed retrospectively in a therapeutic drug-monitoring (TDM) database comprising 94 patients. In addition, three patients received venlafaxine and melperone concomitantly a…
Doxepin and its metabolites in plasma and cerebrospinal fluid in depressed patients
1997
Little information exists on the concentrations of antidepressants and their metabolites in CSF. We measured plasma and CSF levels of trans-doxepin (trans-DOX) and DOX metabolites in 12 depressed patients treated with DOX (250 mg/day) for 6 days. Spinal taps and blood samples were taken on day 7, 10 h after drug administration. Trans-DOX, cis-desmethyldoxepin (cis-DM-DOX), trans-desmethyldoxepin (trans-DM-DOX) and di-desmethyldoxepin (DDM-DOX) were analyzed in CSF and plasma samples by HPLC with column-switching. Although DOX was given as a mixture of 85% trans-DOX and 15% of the pharmacologically more active cis-DOX, we found similar amounts of cis-DM-DOX and trans-DM-DOX in plasma (59.8 +…
Concentrations of 9-Tetrahydrocannabinol and 11-Nor-9-Carboxytetrahydrocannabinol in Blood and Urine After Passive Exposure to Cannabis Smoke in a C…
2010
Cannabinoid concentrations in blood and urine after passive exposure to cannabis smoke under real-life conditions were investigated in this study. Eight healthy volunteers were exposed to cannabis smoke for 3 h in a well-attended coffee shop in Maastricht, Netherlands. An initial blood and urine sample was taken from each volunteer before exposure. Blood samples were taken 1.5, 3.5, 6, and 14 h after start of initial exposure, and urine samples were taken after 3.5, 6, 14, 36, 60, and 84 h. The samples were subjected to immunoassay screening for cannabinoids and analyzed using gas chromatography-mass spectrometry (GC-MS) for Delta(9)-tetrahydrocannabinol (THC), 11-nor-hydroxy-Delta(9)-tetra…
Alteration of vancomycin pharmacokinetics during cardiopulmonary bypass in patients undergoing cardiac surgery.
2003
The alteration of vancomycin pharmacokinetics during cardiopulmonary bypass (CPB) in patients undergoing cardiac surgery was studied. Eighteen patients were enrolled in the study. Vancomycin (1 g) was intravenously infused one to two hours before surgery. Blood samples were taken before, during, and after CPB. Serum drug concentrations were determined by an automated fluorescence polarization immunoassay and adjusted, with a bayesian analysis, to a bi-compartmental model implemented in a pharmacokinetic system program. Serum creatinine, hematocrit, and plasma proteins were also measured before, during, and after CPB. During CPB, serum creatinine, hematocrit, and plasma protein values all de…
Opioid Plasma Concentrations during a Switch from Transdermal Fentanyl to Methadone
2007
Opioid switching is often used to improve the opioid response in patients with cancer experiencing poor analgesia or adverse effects. When switching between drugs with delayed effect because of pharmacokinetics or type of delivery, concerns exist about the correct timing of introducing the second drug after stopping the previous one. The aim of this study was to assess plasmatic changes of fentanyl and methadone underlying the clinical events occurring during opioid switching. Eighteen patients with cancer receiving transdermal fentanyl with uncontrolled pain and/or moderate to severe opioid adverse effects, were switched to oral methadone using an initial fixed ratio of 1:20. Fentanyl patc…
Plasma levels of benperidol, prolactin, and homovanillic acid after intravenous versus two different kinds of oral application of the neuroleptic in …
2009
Plasma levels of prolactin (PRL) and the butyrophenone neuroleptic benperidol (BPD) were closely followed 0 to 48 h after acute application of 6 mg BPD as intravenous injection, orally as liquid, and orally as tablets in 12 schizophrenic patients using a partially randomized cross over design. Drug concentrations showed application specific pharmacokinetic behavior with complete elimination within 48 h. All three applications led to a biphasic PRL response with pronounced initial plasma PRL peaks returning to baseline levels within 48 h. The results suggest that after acute neuroleptic challenge BPD plasma levels as low as 2-3 ng/ml can be sufficient for complete depletion of pituitary PRL …
High-dose short-term administration of naringin did not alter talinolol pharmacokinetics in humans.
2015
Naringin is considered the major causative ingredient of the inhibition of intestinal drug uptake by grapefruit juice. Moreover, it is contained in highly dosed nutraceuticals available on the market. A controlled, open, randomized, crossover study was performed in 10 healthy volunteers to investigate the effect of high-dose naringin on the bioavailability of talinolol, a substrate of intestinal organic anion-transporting polypeptide (OATP)-mediated uptake. Following 6-day supplementation with 3 capsules of 350 mg naringin daily, 100mg talinolol were administered orally with 3 capsules of the same dietary supplement (1050 mg naringin) on the seventh day. This test treatment was compared to …
The enantiomers of phenprocoumon: pharmacodynamic and pharmacokinetic studies.
1976
The pharmacodynamics and pharmacokinetics of the optical enantiomers of phenprocoumon were studied in 5 normal subjects and compared to the racemic mixture. Each subject received a single oral dose of 0.6 mg/kg of racemic, S(-), and R(+) phenprocoumon. S(-) phenprocoumon was 1.6 to 2.6 times as a potent as R(+) phenprocoumon when the area under the effect/time curve was used to quantify the total anticoagulant effect per dose. Comparing the plasma concentrations that elicited the same anticoagulant effect, S(-) phenprocoumon was 1.5 to 2.5 times as potent as R(+) phenprocoumon. The anticoagulant activity of the racemic mixture was between that of the enantiomers. There was no distinct diffe…
Bilateral ureteral obstruction and renal failure caused by massive retroperitoneal hematoma: is there a pelvic compartment syndrome analogous to abdo…
1998
Objectives: To describe an intrapelvic compartment syndrome analogous to abdominal compartment syndrome and to characterize its diagnosis and treatment. Design: Retrospective analysis. Setting: Level I trauma center. Patients: Three patients with pelvic ring or acetabular fractures presented with bilateral ureteral obstruction, renal organ failure. and anuria due to direct compression of both ureters in the true pelvis by a massive retroperitoneal hematoma, Intervention: Surgical therapy consisted of fracture stabilization, decompression of the retroperitoneal space, and evacuation of the hematoma. Persistent isolated bleeding points were either embolized preoperatively or ligated. Results:…