Saturable pharmacokinetics and paclitaxel pharmacodynamics in children with solid tumors.

1994 ◽  
Vol 12 (3) ◽  
pp. 532-538 ◽  
Author(s):  
D S Sonnichsen ◽  
C A Hurwitz ◽  
C B Pratt ◽  
J J Shuster ◽  
M V Relling
Keyword(s):  
Solid Tumors ◽  
High Performance ◽  
Phase 1 ◽  
Plasma Concentrations ◽  
Systemic Exposure ◽  
Compartment Model ◽  
Data Sets ◽  
Pharmacokinetics And Pharmacodynamics ◽  
Time Curve ◽  
Elimination Clearance

PURPOSE Our aim was to evaluate the pharmacokinetics and pharmacodynamics of paclitaxel (Taxol; Bristol-Myers Squibb Co, Princeton, NJ) in children, and to determine whether paclitaxel exhibited saturable pharmacokinetics. PATIENTS AND METHODS We evaluated the pharmacokinetics and pharmacodynamics of paclitaxel (200 to 420 mg/m2) administered as a 24-hour intravenous (i.v.) infusion in a phase 1 study of 30 pediatric patients (age, 2.3 to 22.8 years) with refractory solid tumors. Fourteen serial blood samples were obtained during and up to 48 hours after the infusion, and paclitaxel concentrations were measured by a high-performance liquid chromatography-UV (HPLC-UV) method. Four pharmacokinetic models were compared for their ability to describe the patients' data. RESULTS Paclitaxel disposition was not consistent with a first-order, two-compartment pharmacokinetic model. Rather, the majority of data sets were best described by a two-compartment model that incorporated both saturable tissue distribution and saturable elimination; a smaller number of patient data sets were best described by models that incorporated either saturable distribution or saturable elimination. Clearance was dose-dependent, with a median clearance at the lower dosages (< 400 mg/m2) of 161 mL/min/m2, and at the highest dosages (> 400 mg/m2) of 123 mL/min/m2 (P = .044). The duration that paclitaxel plasma concentrations exceeded 0.1 mumol/L was highly variable (range, 26 to 71 hours). There was a trend toward higher median area under the concentration-versus-time curve (AUC) in those children with musculoskeletal (72 mumol/L.h; P = .054) or neurologic toxicity (54 mumol/L.h; P = .062) versus those without toxicity (30 mumol/L.h). Toxicity was not significantly correlated with dosage. CONCLUSION We conclude that paclitaxel distribution and elimination are saturable, and that estimates of paclitaxel systemic exposure correlate better with toxicity than does dosage.

Clinical pharmacodynamics of continuous infusion topotecan in children: systemic exposure predicts hematologic toxicity.

1994 ◽  
Vol 12 (9) ◽  
pp. 1946-1954 ◽  
Author(s):  
C F Stewart ◽  
S D Baker ◽  
R L Heideman ◽  
D Jones ◽  
W R Crom ◽  
...  
Keyword(s):  
Continuous Infusion ◽  
High Performance ◽  
Plasma Concentrations ◽  
Systemic Exposure ◽  
Compartment Model ◽  
Maximum Effect ◽  
Hematologic Toxicity ◽  
Time Curve ◽  
Steady State Plasma Concentration ◽  
Plasma And Urine Samples

PURPOSE Topotecan pharmacokinetics and pharmacodynamics were studied following a 72-hour continuous infusion in 20 children with cancer (median age, 8 years; range, 3.5 to 18). METHODS Serial plasma and urine samples were collected during the infusion and for up to 6 hours following the end of infusion. Topotecan (lactone) and total (lactone plus hydroxy acid) concentrations were determined by a sensitive and specific high-performance liquid chromatography (HPLC) assay with fluorescence detection. Using maximum a posteriori-Bayesian modeling, lactone and total plasma concentrations were described separately by a two-compartment model. Hematologic toxicity was expressed as the percent decrease in absolute neutrophil count (ANC) and platelet count. The relation between systemic exposure (SE) and hematologic toxicity was modeled using a sigmoid maximum-effect model. RESULTS Systemic clearance rates for lactone and total topotecan were (mean +/- SD) 18.5 +/- 7.0 and 6.5 +/- 2.4 L/h/m2, respectively. Urinary recovery of total topotecan was (mean +/- SD) 67.5% +/- 25.2% (n = 12 patients). SE (area under the concentration-time curve from zero to infinity [AUC] or steady-state plasma concentration [Cpss]) to either topotecan lactone or total topotecan was significantly correlated to hematologic toxicity (P < .05). Overall, patients with a higher SE to topotecan experienced greater hematologic toxicity. CONCLUSION These data demonstrate a relation between systemic exposure to topotecan and clinical effect (myelosuppression). Moreover, these data provide the basis for development of individualized topotecan administration schedules.

Phase I and Pharmacokinetic Study of a Daily Times 5 Short Intravenous Infusion Schedule of 9-Aminocamptothecin in a Colloidal Dispersion Formulation in Patients With Advanced Solid Tumors

1999 ◽  
Vol 17 (6) ◽  
pp. 1906-1906 ◽  
Author(s):  
Virginie M.M. Herben ◽  
Roel van Gijn ◽  
Jan H.M. Schellens ◽  
Margaret Schot ◽  
Jan Lieverst ◽  
...  
Keyword(s):  
Solid Tumors ◽  
High Performance ◽  
Plasma Concentrations ◽  
Colloidal Dispersion ◽  
Maximum Tolerated Dose ◽  
Hematologic Toxicity ◽  
Time Curve ◽  
Infusion Schedule ◽  
Recommended Phase Ii Dose ◽  
Dose Levels

PURPOSE: To determine the maximum-tolerated dose (MTD), dose-limiting toxicities (DLT), and pharmacokinetics of 9-aminocamptothecin (9-AC) in a colloidal dispersion (CD) formulation administered as a 30-minute intravenous (IV) infusion over 5 consecutive days every 3 weeks. PATIENTS AND METHODS: Patients with solid tumors refractory to standard therapy were entered onto the study. The starting dose was 0.4 mg/m2/d. The MTD was assessed on the first cycle and was defined as the dose at which ≥ two of three patients or ≥ two of six patients experience DLT. Pharmacokinetic measurements were performed on days 1 and 5 of the first cycle and on day 4 of subsequent cycles using high-performance liquid chromatography. RESULTS: Thirty-one patients received 104+ treatment courses at seven dose levels. The DLT was hematologic. At a dose of 1.3 mg/m2/d, three of six patients experienced grade 3 thrombocytopenia. Grade 4 neutropenia that lasted less than 7 days was observed in four patients. At a dose of 1.1 mg/m2/d, four of nine patients had grade 4 neutropenia of brief duration, which was not dose limiting. Nonhematologic toxicities were relatively mild and included nausea/vomiting, diarrhea, obstipation, mucositis, fatigue, and alopecia. Maximal plasma concentrations and area under the concentration-time curve (AUC) increased linearly with dose, but interpatient variation was wide. Lactone concentrations exceeded 10 nmol/L, the threshold for activity in preclinical tumor models, at all dose levels. Sigmoidal Emax models could be fit to the relationship between AUC and the degree of hematologic toxicity. A partial response was observed in small-cell lung cancer. CONCLUSION: 9-AC CD administered as a 30-minute IV infusion daily times 5 every three weeks is safe and feasible. The recommended phase II dose is 1.1 mg/m2/d.

Phase 1b/2a study of PLX2853, a small molecule BET inhibitor, in subjects with advanced solid tumors and lymphoma.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 3018-3018
Author(s):  
Michael S. Gordon ◽  
Richard D. Carvajal ◽  
Alexander I. Spira ◽  
Marilyn Huang ◽  
Paul Watkins ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Solid Tumors ◽  
Uveal Melanoma ◽  
Small Molecule ◽  
Thromboembolic Event ◽  
Mononuclear Cells ◽  
Plasma Concentrations ◽  
Systemic Exposure ◽  
Clinical Activity ◽  
Bet Inhibitor

3018 Background: PLX2853 is a potent, orally active small molecule BET inhibitor. Its unique pharmacokinetic (PK) profile is associated with less thrombocytopenia and improved tolerability by allowing transient target engagement with a prolonged pharmacodynamic (PD) response and time for recovery after dosing. Methods: We conducted a first-in-human 3+3 Ph1b/2a study of PLX2853 in adults with relapsed or refractory solid tumors and lymphoma to determine the safety, PK and recommended phase II dose (RP2D) (NCT03297424). Secondary endpoints included efficacy and PD. Results: As of 2 February 2021, 44 subjects (median age 65, range 39 - 84) received PLX2853 in escalating doses from 5mg to 120mg QD and 40mg to 60mg BID. Ovarian cancer (n = 11), uveal melanoma, colorectal, and prostate (n = 5 each) were the most represented tumor types. Adverse events (AE) occurring in ≥15% of subjects included nausea (41%), decrease appetite (39%), fatigue (27%), vomiting (25%), diarrhea (25%), dysgeusia (25%), dehydration (23%), anemia (20%), dry mouth (18%), dizziness (16%), abdominal pain (16%), and pyrexia (16%). Thrombocytopenia occurred in 11% of subjects. Most AEs ( > 85%) were grades (G) 1-2. Of all AEs, 40% were related. There were 5 treatment-related serious AEs in 2 subjects (n = 1 G4 thrombocytopenia, G4 ischemic stroke, G3 subarachnoid hemorrhage [SAH], and G3 thromboembolic event; n = 1 G3 vomiting). Dose-limiting toxicities were observed at 120mg QD (G4 thrombocytopenia, G4 ischemic stroke, G3 thromboembolic event, and G3 SAH; asymptomatic G4 thrombocytopenia), 60mg BID (G3 thrombocytopenia with recovery > 7 days), and 40mg BID (dose reduction for transient G3 fatigue). PLX2853 systemic exposure was dose-proportional up to 120mg with a short terminal half-life ( < 3.5 hr). Plasma concentrations were above the IC90 in the MYC-responsive reporter assay for 9 hr at 80mg or higher doses. RNA-seq analyses of peripheral blood mononuclear cells showed a dose-dependent modulation of BET target gene expression. One complete response (ongoing 9+ months) was seen in a patient with DLBCL, two patients had partial responses (1 uveal melanoma, 1 primary peritoneal cancer), and 14 patients had stable disease. The median PFS was 82.5 days (range: 51 – 209 days). Conclusions: PLX2853 shows encouraging signs of clinical activity and is well tolerated at the anticipated RP2D of 80 mg/day. PLX2853 is being evaluated as monotherapy and in combination. Clinical trial information: NCT03297424.

scholarly journals Comparison of Plasma, Epithelial Lining Fluid, and Alveolar Macrophage Concentrations of Solithromycin (CEM-101) in Healthy Adult Subjects

2012 ◽  
Vol 56 (10) ◽  
pp. 5076-5081 ◽  
Author(s):  
Keith A. Rodvold ◽  
Mark H. Gotfried ◽  
J. Gordon Still ◽  
Kay Clark ◽  
Prabhavathi Fernandes
Keyword(s):  
Steady State ◽  
High Performance ◽  
Healthy Adult ◽  
Plasma Concentrations ◽  
Epithelial Lining ◽  
Time Curve ◽  
Epithelial Lining Fluid ◽  
Once Daily ◽  
Drug Concentrations ◽  
The Mean

ABSTRACTThe steady-state concentrations of solithromycin in plasma were compared with concomitant concentrations in epithelial lining fluid (ELF) and alveolar macrophages (AM) obtained from intrapulmonary samples during bronchoscopy and bronchoalveolar lavage (BAL) in 30 healthy adult subjects. Subjects received oral solithromycin at 400 mg once daily for five consecutive days. Bronchoscopy and BAL were carried out once in each subject at either 3, 6, 9, 12, or 24 h after the last administered dose of solithromycin. Drug concentrations in plasma, ELF, and AM were assayed by a high-performance liquid chromatography-tandem mass spectrometry method. Solithromycin was concentrated extensively in ELF (range of mean [± standard deviation] concentrations, 1.02 ± 0.83 to 7.58 ± 6.69 mg/liter) and AM (25.9 ± 20.3 to 101.7 ± 52.6 mg/liter) in comparison with simultaneous plasma concentrations (0.086 ± 0.070 to 0.730 ± 0.692 mg/liter). The values for the area under the concentration-time curve from 0 to 24 h (AUC0–24values) based on mean and median ELF concentrations were 80.3 and 63.2 mg · h/liter, respectively. The ratio of ELF to plasma concentrations based on the mean and median AUC0–24values were 10.3 and 10.0, respectively. The AUC0–24values based on mean and median concentrations in AM were 1,498 and 1,282 mg · h/L, respectively. The ratio of AM to plasma concentrations based on the mean and median AUC0–24values were 193 and 202, respectively. Once-daily oral dosing of solithromycin at 400 mg produced steady-state concentrations that were significantly (P< 0.05) higher in ELF (2.4 to 28.6 times) and AM (44 to 515 times) than simultaneous plasma concentrations throughout the 24-h period after 5 days of solithromycin administration.

scholarly journals Pharmacokinetics of Doxycycline in Adults with Cystic Fibrosis

2011 ◽  
Vol 56 (1) ◽  
pp. 70-74 ◽  
Author(s):  
Paul M. Beringer ◽  
Heather Owens ◽  
Albert Nguyen ◽  
Debbie Benitez ◽  
Adupa Rao ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Oral Administration ◽  
Maximum Concentration ◽  
Airway Remodeling ◽  
Plasma Concentrations ◽  
Compartment Model ◽  
Time Curve ◽  
Elimination Half ◽  
Dose Oral

ABSTRACTCystic fibrosis (CF) is characterized by a chronic neutrophilic inflammatory response resulting in airway remodeling and progressive loss of lung function. Doxycycline is a tetracycline antibiotic that inhibits matrix metalloproteinase 9, a protease known to be associated with the severity of lung disease in CF. The pharmacokinetics of doxycycline was investigated during the course of a clinical trial to evaluate the short-term efficacy and safety in adults with CF. Plasma samples were obtained from 14 patients following a single intravenous dose and after 2 and 4 weeks of oral administration of doses ranging from 40 to 200 mg daily. The data were analyzed using noncompartmental and compartmental pharmacokinetics. The maximum concentration of drug in serum (Cmax) and area under the concentration-time curve from 0 h to infinity (AUC0-∞) values ranged from 1.0 to 3.16 mg/liter and 15.2 to 47.8 mg/liter × h, respectively, following single intravenous doses of 40 to 200 mg.Cmaxand time to maximum concentration of drug in serum (Tmax) values following multiple-dose oral administration ranged from 1.15 to 3.04 mg/liter and 1.50 to 2.33 h, respectively, on day 14 and 1.48 to 3.57 mg/liter and 1.00 to 2.17 on day 28. Predose sputum/plasma concentration ratios on days 14 and 28 ranged from 0.33 to 1.1 (mean, 0.71 ± 0.33), indicating moderate pulmonary penetration. A 2-compartment model best described the combined intravenous and oral data. Absorption was slow and delayed (absorption rate constant [Ka], 0.414 h−1; lag time, 0.484 h) but complete (bioavailability [F], 1.16). The distribution and elimination half-lives were 0.557 and 18.1 h, respectively. Based on these data, the plasma concentrations at the highest dose, 200 mg/day, are in the range reported to produce anti-inflammatory effectsin vivoand should be evaluated in clinical trials.

scholarly journals Pharmacokinetics and pharmacodynamics of two multiple-dose piperacillin-tazobactam regimens.

1997 ◽  
Vol 41 (11) ◽  
pp. 2511-2517 ◽  
Author(s):  
D J Occhipinti ◽  
S L Pendland ◽  
L L Schoonover ◽  
E B Rypins ◽  
L H Danziger ◽  
...  
Keyword(s):  
Bactericidal Activity ◽  
Dosage Regimen ◽  
Multiple Dose ◽  
Antimicrobial Agents ◽  
Plasma Concentrations ◽  
Culture Collection ◽  
Beta Lactam ◽  
Pharmacokinetics And Pharmacodynamics ◽  
Time Curve ◽  
Bacteriological Response

The pharmacokinetics and pharmacodynamics of two multiple-dose regimens of piperacillin-tazobactam (3.375 g every 6 h and 4.5 g every 8 h) were evaluated at steady state for 12 healthy adult volunteers. Inhibitory and bactericidal activities for the two regimens were determined with five American Type Culture Collection (ATCC) organisms (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Bacteroides fragilis). The percentage of time that plasma concentrations remained above the MIC (T > MIC) for each organism and dosage regimen was calculated. Areas under the inhibitory (AUIC0-24) and bactericidal activity (AUBC0-24) curves were calculated with the trapezoidal rule by using the reciprocal of the inhibitory and bactericidal titers determined for each dosage regimen. In order to assess the validity of predicted measures of bactericidal (AUC0-24/MBC) and inhibitory (AUC0-24/MIC) activity to determine bacteriological response to beta-lactam antimicrobial agents, AUC0-24/MBC and AUC0-24/MIC values were compared with measured AUBC0-24 and AUIC0-24 values. Total body clearance values were equivalent for piperacillin (183.96 +/- 22.66 versus 181.72 +/- 19.54 ml/min/1.73 m2, P > 0.05) and tazobactam (184.71 +/- 19.89 versus 184.87 +/- 18.35 ml/min/1.73 m2, P > 0.05) following the administration of the 3.375-g-every-6-h and 4.5-g-every-8-h dosages, respectively. Comparison of area under the plasma concentration-time curve (AUC0-24) for piperacillin (967.74 +/- 135.56 microg x h/ml versus 978.88 +/- 140.96 microg x h/ml) and tazobactam (120.14 +/- 15.78 microg x h/ml versus 120.01 +/- 16.22 microg x h/ml) revealed no significant differences (P > 0.05) between the 3.375-g-every-6-h and 4.5-g-every-8-h regimens, respectively. Both regimens provided T > MIC values of > 60% for all organisms tested. Measured values of bactericidal (AUBC) and inhibitory (AUIC) activity were significantly different (P < 0.05) from predicted values (AUC0-24/MBC and AUC0-24/MIC) for all organisms studied with the exception of the bactericidal activity for P. aeruginosa and S. aureus. Additionally, ATCC organisms possessing the same MICs and MBCs exhibited great differences in measured AUBC0-24 and AUIC0-24 values. Reasons for this difference may be inherent differences in organism specific susceptibility.

scholarly journals 1335. Safety and Pharmacokinetic Profile of PC786, a Novel Inhibitor of Respiratory Syncytial Virus L-protein Polymerase, in a Single and Multiple-Ascending Dose Study in Healthy Volunteer and Mild Asthmatics

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S407-S408
Author(s):  
Lindsey Cass ◽  
Amanda Davis ◽  
Alison Murray ◽  
Kathy Woodward ◽  
Kazuhiro Ito ◽  
...  
Keyword(s):  
Half Life ◽  
Board Member ◽  
Phase 1 ◽  
Geometric Mean ◽  
Plasma Concentrations ◽  
Systemic Exposure ◽  
Preclinical Studies ◽  
Laboratory Findings ◽  
L Protein ◽  
Syncytial Virus

Abstract Background RSV is the most common cause of bronchiolitis in infants and is responsible for severe respiratory infections in the elderly and immunocompromised populations. RSV replicates in the columnar epithelial cells of the proximal and distal airways which are accessible to inhaled therapies. PC786 is a potent non-nucleoside RSV L-protein polymerase inhibitor designed for inhaled delivery. In preclinical studies, PC786 exhibits prolonged lung tissue residence with minimal systemic exposure, thus limiting the potential for adverse systemic effects. Methods A phase 1 study was conducted to evaluate the safety and pharmacokinetics of PC786 delivered in a suspension formulation by nebulizer (PARI LC SPRINT® device). Healthy volunteers (HVs) received placebo or PC786 as single ascending doses (0.5–20 mg, Cohort (C) 1), 5 mg BD for 7 days (C2), or 10 mg BD for 7 days (C3). Mild asthmatics received a single dose of PC786 5 mg or placebo (C4). PC786 PK was measured in plasma and in nasal mucosal lining fluid (MLF) collected using a synthetic absorptive matrix. Results PC786 was well tolerated, with no significant adverse clinical nor laboratory findings. Following single inhaled doses PC786 appeared rapidly in the plasma; mean plasma Cmax of 190, 571, 1,760, and 3,270 pg/mL, for the 0.5, 2, 8, and 20 mg doses, respectively, were measured on average at 0.68 to 0.93 hours (Tmax) post-inhalation. Following administration of 5 mg BD (C2) the extent of accumulation was approximately 2-fold. The geometric mean apparent terminal half-life measured following 10 mg BD (C3) was 97 hours. The ratio of MLF:plasma concentrations ranged from 6,347 (+2 hours) to 1,050 (+24h). Conclusion PC786 was well tolerated by HVs and asthmatics. The compound showed a rapid Tmax, suggesting rapid exposure of the respiratory epithelium. The PC786 concentrations in MLF exceed the IC90 for RSV, but circulating plasma concentrations were low. The MLF:plasma measured in this study was consistent with lung:plasma ratios measured in preclinical studies. The long plasma half-life is consistent with slow absorption from the lung being the dominant process controlling systemic kinetic behavior. The long t½ and 2-fold accumulation ratio observed on repeat dosing supports once daily dosing in subsequent studies. Disclosures L. Cass, Pulmocide Ltd.: Employee and Shareholder, Salary. A. Davis, Pulmocide Ltd.: Employee and Shareholder, Salary. A. Murray, Pulmocide Ltd.: Employee and Shareholder, Salary. K. Woodward, Pulmocide Ltd.: Consultant, Consulting fee. K. Ito, Pulmocide Ltd.: Employee and Shareholder, Salary. P. Strong, Pulmocide Ltd.: Board Member, Employee and Shareholder, Salary. G. Rapeport, Pulmocide Ltd.: Board Member, Employee and Shareholder, Salary.

Increased teniposide clearance with concomitant anticonvulsant therapy.

1992 ◽  
Vol 10 (2) ◽  
pp. 311-315 ◽  
Author(s):  
D K Baker ◽  
M V Relling ◽  
C H Pui ◽  
M L Christensen ◽  
W E Evans ◽  
...  
Keyword(s):  
High Performance ◽  
Pediatric Patients ◽  
Plasma Concentrations ◽  
Substantial Reduction ◽  
Systemic Exposure ◽  
Pharmacokinetic Interaction ◽  
Lymphocytic Leukemia ◽  
Control Group ◽  
Systemic Clearance ◽  
The Mean

PURPOSE A possible pharmacokinetic interaction between teniposide and anticonvulsant medications was evaluated in pediatric patients. PATIENTS AND METHODS The systemic clearance of teniposide was determined in six pediatric patients with acute lymphocytic leukemia receiving concomitant therapy with anticonvulsants. Clearance was then compared with a control group of patients treated with the same protocol therapy and matched for age at diagnosis, sex, and race but not receiving anticonvulsants or other agents known to induce hepatic metabolism or alter protein binding of drugs. Eight blood samples were obtained during and after 4-hour infusions of teniposide, and plasma concentrations were measured by a specific high-performance liquid chromatography (HPLC) assay. A two-compartment model was fitted to each subject's data. RESULTS The mean systemic clearance (range) for the six anticonvulsant-treated patients studied during 22 courses of therapy was 32 mL/min/m2 (range, 21 to 54 mL/min/m2), significantly higher (P less than .001) than the mean value of 13 mL/min/m2 (range, 7 to 17 mL/min/m2) for the control patients studied during 26 courses of therapy. Clearance estimates for control patients were similar to previously published values for pediatric patients. CONCLUSION These data indicate that the systemic clearance of teniposide is consistently increased two- to three-fold by concomitant phenobarbital or phenytoin therapy. The consequent substantial reduction in systemic exposure may reduce teniposide's efficacy.

scholarly journals Effects of Verapamil and Diltiazem on the Pharmacokinetics and Pharmacodynamics of Rivaroxaban

Pharmaceutics ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 133 ◽  
Author(s):  
Minsoo Kim ◽  
Heebin Son ◽  
Keumhan Noh ◽  
Eunyoung Kim ◽  
Beom Shin ◽  
...  
Keyword(s):  
Prothrombin Time ◽  
Plasma Concentrations ◽  
Systemic Exposure ◽  
Point Of View ◽  
Channel Blockers ◽  
Absorption Process ◽  
Pharmacokinetics And Pharmacodynamics ◽  
Double Peaks ◽  
Simple Linear Relationship ◽  
Rivaroxaban Plasma Concentration

Concomitant use of rivaroxaban with non-dihydropyridine calcium channel blockers (non-DHPs) might lead to an increase of systemic rivaroxaban exposure and anticoagulant effects in relation to the inhibition of metabolic enzymes and/or transporters by non-DHPs. This study was designed to evaluate the effects of verapamil and diltiazem on the pharmacokinetics and the prolongation of prothrombin time of rivaroxaban in rats. The data were analyzed using a pharmacokinetic/pharmacodynamics (PK/PD) modeling approach to quantify the influence of verapamil. Verapamil increased the systemic exposure of rivaroxaban by 2.8-fold (p <0.001) which was probably due to the inhibition of efflux transportation rather than metabolism. Prothrombin time was also prolonged in a proportional manner; diltiazem did not show any significant effects, however. A transit PK model in the absorption process comprehensively describes the double-peaks of rivaroxaban plasma concentrations and the corresponding change of prothrombin time with a simple linear relationship. The slope of prothrombin time vs. rivaroxaban plasma concentration in rats was retrospectively found to be insensitive by about 5.4-fold compared to than in humans. More than a 67% dose reduction in rivaroxaban is suggested in terms of both a pharmacokinetic point of view, and the sensitivity differences on the prolongation of prothrombin time when used concomitantly with verapamil.

Sign in / Sign up

Export Citation Format

Share Document