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1.
Circulation ; 146(23): 1735-1745, 2022 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-36335914

RESUMO

BACKGROUND: There are no randomized data evaluating the safety or efficacy of apixaban for stroke prevention in patients with end-stage kidney disease on hemodialysis and with atrial fibrillation (AF). METHODS: The RENAL-AF trial (Renal Hemodialysis Patients Allocated Apixaban Versus Warfarin in Atrial Fibrillation) was a prospective, randomized, open-label, blinded-outcome evaluation (PROBE) of apixaban versus warfarin in patients receiving hemodialysis with AF and a CHA2DS2-VASc score ≥2. Patients were randomly assigned 1:1 to 5 mg of apixaban twice daily (2.5 mg twice daily for patients ≥80 years of age, weight ≤60 kg, or both) or dose-adjusted warfarin. The primary outcome was time to major or clinically relevant nonmajor bleeding. Secondary outcomes included stroke, mortality, and apixaban pharmacokinetics. Pharmacokinetic sampling was day 1, day 3, and month 1. RESULTS: From January 2017 through January 2019, 154 patients were randomly assigned to apixaban (n=82) or warfarin (n=72). The trial stopped prematurely because of enrollment challenges. Time in therapeutic range (international normalized ratio, 2.0-3.0) for warfarin-treated patients was 44% (interquartile range, 23%-59%). The 1-year rates for major or clinically relevant nonmajor bleeding were 32% and 26% in apixaban and warfarin groups, respectively (hazard ratio, 1.20 [95% CI, 0.63-2.30]), whereas 1-year rates for stroke or systemic embolism were 3.0% and 3.3% in apixaban and warfarin groups, respectively. Death was the most common major event in the apixaban (21 patients [26%]) and warfarin (13 patients [18%]) arms. The pharmacokinetic substudy enrolled the target 50 patients. Median steady-state 12-hour area under the curve was 2475 ng/mL×h (10th to 90th percentiles, 1342-3285) for 5 mg of apixaban twice daily and 1269 ng/mL×h (10th to 90th percentiles, 615-1946) for 2.5 mg of apixaban twice daily. There was substantial overlap between minimum apixaban blood concentration, 12-hour area under the curve, and maximum apixaban blood concentration for patients with and without a major or clinically relevant nonmajor bleeding event. CONCLUSIONS: There was inadequate power to draw any conclusion regarding rates of major or clinically relevant nonmajor bleeding comparing apixaban and warfarin in patients with AF and end-stage kidney disease on hemodialysis. Clinically relevant bleeding events were ≈10-fold more frequent than stroke or systemic embolism among this population on anticoagulation, highlighting the need for future randomized studies evaluating the risks versus benefits of anticoagulation among patients with AF and end-stage kidney disease on hemodialysis. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02942407.


Assuntos
Fibrilação Atrial , Embolia , Falência Renal Crônica , Acidente Vascular Cerebral , Humanos , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/tratamento farmacológico , Fibrilação Atrial/complicações , Varfarina/efeitos adversos , Anticoagulantes/uso terapêutico , Estudos Prospectivos , Resultado do Tratamento , Hemorragia/epidemiologia , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/etiologia , Embolia/prevenção & controle , Diálise Renal/efeitos adversos , Falência Renal Crônica/complicações , Falência Renal Crônica/diagnóstico , Falência Renal Crônica/terapia
2.
Circulation ; 141(17): 1384-1392, 2020 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-32160801

RESUMO

BACKGROUND: Compared with the general population, patients with advanced chronic kidney disease have a >10-fold higher burden of atrial fibrillation. Limited data are available guiding the use of nonvitamin K antagonist oral anticoagulants in this population. METHODS: We compared the safety of apixaban with warfarin in 269 patients with atrial fibrillation and advanced chronic kidney disease (defined as creatinine clearance [CrCl] 25 to 30 mL/min) enrolled in the ARISTOTLE trial (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation). Cox proportional models were used to estimate hazard ratios for major bleeding and major or clinically relevant nonmajor bleeding. We characterized the pharmacokinetic profile of apixaban by assessing differences in exposure using nonlinear mixed effects models. RESULTS: Among patients with CrCl 25 to 30 mL/min, apixaban caused less major bleeding (hazard ratio, 0.34 [95% CI, 0.14-0.80]) and major or clinically relevant nonmajor bleeding (hazard ratio, 0.35 [95% CI, 0.17-0.72]) compared with warfarin. Patients with CrCl 25 to 30 mL/min randomized to apixaban demonstrated a trend toward lower rates of major bleeding when compared with those with CrCl >30 mL/min (P interaction=0.08) and major or clinically relevant nonmajor bleeding (P interaction=0.05). Median daily steady-state areas under the curve for apixaban 5 mg twice daily were 5512 ng/(mL·h) and 3406 ng/(mL·h) for patients with CrCl 25 to 30 mL/min or >30 mL/min, respectively. For apixaban 2.5 mg twice daily, the median exposure was 2780 ng/(mL·h) for patients with CrCl 25 to 30 mL/min. The area under the curve values for patients with CrCl 25 to 30 mL/min fell within the ranges demonstrated for patients with CrCl >30 mL/min. CONCLUSIONS: Among patients with atrial fibrillation and CrCl 25 to 30 mL/min, apixaban caused less bleeding than warfarin, with even greater reductions in bleeding than in patients with CrCl >30 mL/min. We observed substantial overlap in the range of exposure to apixaban 5 mg twice daily for patients with or without advanced chronic kidney disease, supporting conventional dosing in patients with CrCl 25 to 30 mL/min. Randomized, controlled studies evaluating the safety and efficacy of apixaban are urgently needed in patients with advanced chronic kidney disease, including those receiving dialysis. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00412984.


Assuntos
Anticoagulantes , Fibrilação Atrial , Pirazóis , Piridonas , Varfarina , Idoso , Idoso de 80 Anos ou mais , Anticoagulantes/administração & dosagem , Anticoagulantes/efeitos adversos , Anticoagulantes/farmacocinética , Fibrilação Atrial/sangue , Fibrilação Atrial/tratamento farmacológico , Fibrilação Atrial/epidemiologia , Método Duplo-Cego , Feminino , Hemorragia/sangue , Hemorragia/induzido quimicamente , Hemorragia/epidemiologia , Humanos , Masculino , Modelos de Riscos Proporcionais , Pirazóis/administração & dosagem , Pirazóis/efeitos adversos , Pirazóis/farmacocinética , Piridonas/administração & dosagem , Piridonas/efeitos adversos , Piridonas/farmacocinética , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/tratamento farmacológico , Insuficiência Renal Crônica/epidemiologia , Varfarina/administração & dosagem , Varfarina/efeitos adversos , Varfarina/farmacocinética
3.
Arterioscler Thromb Vasc Biol ; 40(11): 2678-2685, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32907366

RESUMO

OBJECTIVE: PAR (protease-activated receptor)-4 antagonism has antiplatelet effects under conditions of high shear stress. We aimed to establish whether PAR4 antagonism had additive antithrombotic activity in the presence of factor Xa inhibition in an ex vivo model of acute arterial injury. Approach and Results: Fifteen healthy volunteers (29±6 years, 7 women) completed a phase zero double-blind randomized controlled crossover trial. Ex vivo platelet activation, platelet aggregation, and thrombus formation were measured following blood perfusion of low shear and high shear stress chambers. Upstream of the chambers, extracorporeal blood was admixed with (1) vehicle, (2) low-dose apixaban (20 ng/mL), (3) high-dose apixaban (80 ng/mL), (4) BMS-986141 (400 ng/mL), (5) BMS-968141 and low-dose apixaban, or (6) BMS-968141 and high-dose apixaban in 6 sequential studies performed in random order. Compared with vehicle, BMS-986141 demonstrated selective inhibition of PAR4-AP (agonist peptide)-stimulated platelet aggregation, platelet-monocyte aggregates, and P-selectin expression (P≤0.01 for all). Total thrombus area was reduced under both low shear and high shear stress conditions for all drug infusions (P<0.0001 for all versus vehicle). BMS-968141 reduced total (≤44.4%) and platelet-rich (≤39.3%) thrombus area, whereas apixaban reduced total (≤42.9%) and fibrin-rich (≤31.6%) thrombus area. Combination of BMS-986141 with apixaban caused a further modest reduction in total thrombus area (9.6%-12.4%), especially under conditions of high shear stress (P≤0.027). CONCLUSIONS: In the presence of factor Xa inhibition, PAR4 antagonism with BMS-986141 further reduces thrombus formation, especially under conditions of high shear stress. This suggests the potential for additive efficacy of combination PAR4 antagonism and factor Xa inhibition in the prevention of atherothrombotic events.


Assuntos
Plaquetas/efeitos dos fármacos , Inibidores do Fator Xa/administração & dosagem , Fibrinolíticos/administração & dosagem , Agregação Plaquetária/efeitos dos fármacos , Pirazóis/administração & dosagem , Piridonas/administração & dosagem , Receptores de Trombina/antagonistas & inibidores , Trombose/prevenção & controle , Adulto , Plaquetas/metabolismo , Método Duplo-Cego , Quimioterapia Combinada , Inibidores do Fator Xa/farmacocinética , Feminino , Fibrinolíticos/farmacocinética , Humanos , Masculino , Pirazóis/farmacocinética , Piridonas/farmacocinética , Receptores de Trombina/sangue , Transdução de Sinais , Trombose/sangue , Adulto Jovem
4.
Arterioscler Thromb Vasc Biol ; 38(2): 448-456, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29269513

RESUMO

OBJECTIVE: BMS-986120 is a novel first-in-class oral PAR4 (protease-activated receptor 4) antagonist with potent and selective antiplatelet effects. We sought to determine for the first time, the effect of BMS-986120 on human ex vivo thrombus formation. APPROACH AND RESULTS: Forty healthy volunteers completed a phase 1 parallel-group PROBE trial (Prospective Randomized Open-Label Blinded End Point). Ex vivo platelet activation, platelet aggregation, and thrombus formation were measured at 0, 2, and 24 hours after (1) oral BMS-986120 (60 mg) or (2) oral aspirin (600 mg) followed at 18 hours with oral aspirin (600 mg) and oral clopidogrel (600 mg). BMS-986120 demonstrated highly selective and reversible inhibition of PAR4 agonist peptide (100 µM)-stimulated P-selectin expression, platelet-monocyte aggregates, and platelet aggregation (P<0.001 for all). Compared with pretreatment, total thrombus area (µm2/mm) at high shear was reduced by 29.2% (95% confidence interval, 18.3%-38.7%; P<0.001) at 2 hours and by 21.4% (9.3%-32.0%; P=0.002) at 24 hours. Reductions in thrombus formation were driven by a decrease in platelet-rich thrombus deposition: 34.8% (19.3%-47.3%; P<0.001) at 2 hours and 23.3% (5.1%-38.0%; P=0.016) at 24 hours. In contrast to aspirin alone, or in combination with clopidogrel, BMS-986120 had no effect on thrombus formation at low shear (P=nonsignificant). BMS-986120 administration was not associated with an increase in coagulation times or serious adverse events. CONCLUSIONS: BMS-986120 is a highly selective and reversible oral PAR4 antagonist that substantially reduces platelet-rich thrombus formation under conditions of high shear stress. Our results suggest PAR4 antagonism has major potential as a therapeutic antiplatelet strategy. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02439190.


Assuntos
Benzofuranos/administração & dosagem , Plaquetas/efeitos dos fármacos , Fibrinolíticos/administração & dosagem , Imidazóis/administração & dosagem , Morfolinas/administração & dosagem , Inibidores da Agregação Plaquetária/administração & dosagem , Agregação Plaquetária/efeitos dos fármacos , Receptores de Trombina/antagonistas & inibidores , Tiazóis/administração & dosagem , Trombose/prevenção & controle , Administração Oral , Adulto , Aspirina/administração & dosagem , Benzofuranos/efeitos adversos , Benzofuranos/farmacocinética , Plaquetas/metabolismo , Clopidogrel/administração & dosagem , Feminino , Fibrinolíticos/efeitos adversos , Fibrinolíticos/farmacocinética , Voluntários Saudáveis , Humanos , Imidazóis/efeitos adversos , Imidazóis/farmacocinética , Masculino , Morfolinas/efeitos adversos , Morfolinas/farmacocinética , Inibidores da Agregação Plaquetária/efeitos adversos , Inibidores da Agregação Plaquetária/farmacocinética , Estudos Prospectivos , Receptores de Trombina/sangue , Escócia , Transdução de Sinais/efeitos dos fármacos , Tiazóis/efeitos adversos , Tiazóis/farmacocinética , Trombose/sangue , Trombose/diagnóstico , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
5.
Drug Metab Dispos ; 46(8): 1075-1082, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29777022

RESUMO

In a recent study, limited to South Asian Indian subjects (n = 12), coproporphyrin (CP) I and CPIII demonstrated properties appropriate for an organic anion-transporting polypeptide (OATP) 1B endogenous probe. The current studies were conducted in healthy volunteers of mixed ethnicities, including black, white, and Hispanic subjects, to better understand the utility of these biomarkers in broader populations. After oral administration with 600 mg rifampin, AUC(0-24h) values were 2.8-, 3.7-, and 3.6-fold higher than predose levels for CPI and 2.6-, 3.1-, and 2.4-fold higher for CPIII, for the three populations, respectively. These changes in response to rifampin were consistent with previous results. The sensitivity toward OATP1B inhibition was also investigated by evaluating changes of plasma CP levels in the presence of diltiazem and itraconazole [administered as part of an unrelated drug-drug interaction (DDI) investigation], two compounds that were predicted to have minimal inhibitory effect on OATP1B. Administration of diltiazem and itraconazole did not increase plasma CPI and CPIII concentrations relative to prestudy levels, in agreement with predictions from in vitro parameters. Additionally, the basal CP concentrations in subjects with SLCO1B1 c.521TT genotype were comparable to those with SLCO1B1 c.521TC genotype, similar to studies with probe substrates. However, subjects with SLCO1B1 c.388AG and c.388GG genotypes (i.e., increased OATP1B1 transport activity for certain substrates) had lower concentrations of CPI than those with SLCO1B1 c.388AA. Collectively, these findings provide further evidence supporting the translational value of CPI and CPIII as suitable endogenous clinical probes to gauge OATP1B activity and potential for OATP1B-mediated DDIs.


Assuntos
Transporte Biológico/fisiologia , Biomarcadores/metabolismo , Coproporfirinas/metabolismo , Transportador 1 de Ânion Orgânico Específico do Fígado/antagonistas & inibidores , Transportadores de Ânions Orgânicos/metabolismo , Membro 1B3 da Família de Transportadores de Ânion Orgânico Carreador de Soluto/antagonistas & inibidores , Adulto , Transporte Biológico/efeitos dos fármacos , Coproporfirinas/genética , Interações Medicamentosas/fisiologia , Genótipo , Humanos , Transportador 1 de Ânion Orgânico Específico do Fígado/genética , Transportador 1 de Ânion Orgânico Específico do Fígado/metabolismo , Masculino , Pessoa de Meia-Idade , Transportadores de Ânions Orgânicos/genética , Rifampina/farmacologia , Membro 1B3 da Família de Transportadores de Ânion Orgânico Carreador de Soluto/genética , Membro 1B3 da Família de Transportadores de Ânion Orgânico Carreador de Soluto/metabolismo , Adulto Jovem
6.
Clin Infect Dis ; 64(5): 565-571, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28011614

RESUMO

Background: Intravenous colistin is difficult to use because plasma concentrations for antibacterial effect overlap those causing nephrotoxicity, and there is large inter-patient variability in pharmacokinetics. The aim was to develop dosing algorithms for achievement of a clinically desirable average steady-state plasma colistin concentration (Css,avg) of 2mg/L. Methods: Plasma concentration-time data from 214 adult critically-ill patients (creatinine clearance 0-236mL/min; 29 receiving renal replacement therapy (RRT)) were subjected to population pharmacokinetic analysis. Development of an algorithm for patients not receiving RRT was based upon the relationship between the dose of colistimethate that would be needed to achieve a desired Css,avg and creatinine clearance. The increase in colistin clearance when patients were on RRT was determined from the population analysis and guided the supplemental dosing needed. To balance potential antibacterial benefit against risk of nephrotoxicity the algorithms were designed to achieve target attainment rates of >80% for Css,avg ≥2 and <30% for Css,avg ≥4mg/L. Results: When algorithm doses were applied back to individual patients not on RRT (including patients prescribed intermittent dialysis on a non-dialysis day), >80% of patients with creatinine clearance <80mL/min achieved Css,avg ≥2mg/L; but for patients with creatinine clearance ≥80mL/min target attainment was <40%, even with the maximum allowed daily dose of 360mg colistin base activity. For patients receiving RRT, target attainment rates were >80% with the proposed supplemental dosing. In all categories of patients, <30% of patients attained Css,avg ≥4mg/L. Conclusions: The project has generated clinician-friendly dosing algorithms and pointed to circumstances where intravenous monotherapy may be inadequate.


Assuntos
Antibacterianos/administração & dosagem , Colistina/administração & dosagem , Estado Terminal/terapia , Administração Intravenosa , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/sangue , Antibacterianos/farmacocinética , Antibacterianos/uso terapêutico , Colistina/sangue , Colistina/farmacocinética , Colistina/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Guias de Prática Clínica como Assunto , Terapia de Substituição Renal , Adulto Jovem
7.
Artigo em Inglês | MEDLINE | ID: mdl-28893780

RESUMO

Acute kidney injury (AKI) occurs in a substantial proportion of critically ill patients receiving intravenous colistin. In the pharmacokinetic/toxicodynamic analysis reported here, the relationship of the occurrence of AKI to exposure to colistin and a number of potential patient factors was explored in 153 critically ill patients, none of whom were receiving renal replacement therapy. Tree-based modeling revealed that the rates of AKI were substantially higher when the average steady-state plasma colistin concentration was greater than ∼2 mg/liter.


Assuntos
Injúria Renal Aguda/induzido quimicamente , Antibacterianos/farmacocinética , Colistina/farmacocinética , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/efeitos adversos , Antibacterianos/sangue , Colistina/efeitos adversos , Colistina/sangue , Creatinina/sangue , Estado Terminal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
8.
J Antimicrob Chemother ; 72(5): 1415-1420, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28333347

RESUMO

Objectives: The emergence of polymyxin resistance threatens to leave clinicians with few options for combatting drug-resistant Acinetobacter baumannii . The objectives of the current investigation were to define the in vitro emergence of polymyxin resistance and identify a combination regimen capable of eradicating A. baumannii with no apparent drug susceptibilities. Methods: Two clonally related, paired, A. baumannii isolates collected from a critically ill patient who developed colistin resistance while receiving colistin methanesulfonate in a clinical population pharmacokinetic study were evaluated: an A. baumannii isolate collected before (03-149.1, polymyxin-susceptible, MIC 0.5 mg/L) and an isolate collected after (03-149.2, polymyxin-resistant, MIC 32 mg/L, carbapenem-resistant, ampicillin/sulbactam-resistant). Using the patient's unique pharmacokinetics, the patient's actual regimen received in the clinic was recreated in a hollow-fibre infection model (HFIM) to track the emergence of polymyxin resistance against 03-149.1. A subsequent HFIM challenged the pan-resistant 03-149.2 isolate against polymyxin B, meropenem and ampicillin/sulbactam alone and in two-drug and three-drug combinations. Results: Despite achieving colistin steady-state targets of an AUC 0-24 >60 mg·h/L and C avg of >2.5 mg/L, colistin population analysis profiles confirmed the clinical development of polymyxin resistance. During the simulation of the patient's colistin regimen in the HFIM, no killing was achieved in the HFIM and amplification of polymyxin resistance was observed by 96 h. Against the polymyxin-resistant isolate, the triple combination of polymyxin B, meropenem and ampicillin/sulbactam eradicated the A. baumannii by 96 h in the HFIM, whereas monotherapies and double combinations resulted in regrowth. Conclusions: To combat polymyxin-resistant A. baumannii , the triple combination of polymyxin B, meropenem and ampicillin/sulbactam holds great promise.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Colistina/farmacologia , Farmacorresistência Bacteriana Múltipla , Polimixina B/farmacologia , Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/microbiologia , Adulto , Antibacterianos/uso terapêutico , Colistina/farmacocinética , Colistina/uso terapêutico , Sinergismo Farmacológico , Quimioterapia Combinada , Humanos , Meropeném , Testes de Sensibilidade Microbiana , Polimixina B/uso terapêutico , Tienamicinas/farmacologia , Tienamicinas/uso terapêutico
9.
Clin Infect Dis ; 62(5): 552-558, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26607424

RESUMO

BACKGROUND: The US Food and Drug Administration (FDA) and European Medicines Agency (EMA) have approved updated dose recommendations for intravenous colistin in patients with various degrees of renal function. We assessed the recommendations in relation to their ability to achieve clinically relevant plasma colistin concentrations. METHODS: Pharmacokinetic data from 162 adult critically ill patients (creatinine clearance range, 5.4-211 mL/min) were used to determine the average steady-state plasma colistin concentration (Css,avg) that would be achieved if each patient received the FDA or EMA dose. Target attainment rates for FDA- and EMA-approved daily doses to achieve colistin Css,avg of ≥0.5, ≥1, ≥2, and ≥4 mg/L were determined for each creatinine clearance category (≥80 mL/min, 50 to <80 mL/min, 30 to <50 mL/min, and <30 mL/min). RESULTS: For creatinine clearance <30 mL/min, 100% of patients receiving the EMA dose achieved a colistin Css,avg ≥1 mg/L, but the attainment rate was as low as 53.1% for patients receiving the FDA-approved dose. For colistin Css,avg ≥2 mg/L, the attainment rates were 87.5% with the EMA dose but only 6.3%-34.4% in patients receiving the FDA dose. Differences in attainment rates for a colistin Css,avg of ≥2 mg/L and ≥4 mg/L extended to patients with creatinine clearance 30 to <50 mL/min. For patients with creatinine clearance ≥80 mL/min, only approximately 65%-75% of patients achieved a colistin Css,avg of ≥1 mg/L with either set of recommendations. CONCLUSIONS: The study highlights important differences between the FDA- and EMA-approved dose recommendations and informs the setting of clinical breakpoints. CLINICAL TRIALS REGISTRATION: NCT00235690.


Assuntos
Colistina/administração & dosagem , Administração Intravenosa , Adulto , Idoso , Idoso de 80 Anos ou mais , Colistina/sangue , Relação Dose-Resposta a Droga , Europa (Continente) , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estados Unidos , Adulto Jovem
10.
Antimicrob Agents Chemother ; 58(3): 1381-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24342636

RESUMO

Increasing evidence suggests that colistin monotherapy is suboptimal at currently recommended doses. We hypothesized that front-loading provides an improved dosing strategy for polymyxin antibiotics to maximize killing and minimize total exposure. Here, we utilized an in vitro pharmacodynamic model to examine the impact of front-loaded colistin regimens against a high bacterial density (10(8) CFU/ml) of Pseudomonas aeruginosa. The pharmacokinetics were simulated for patients with hepatic (half-life [t1/2] of 3.2 h) or renal (t1/2 of 14.8 h) disease. Front-loaded regimens (n=5) demonstrated improvement in bacterial killing, with reduced overall free drug areas under the concentration-time curve (fAUC) compared to those with traditional dosing regimens (n=14) with various dosing frequencies (every 12 h [q12h] and q24h). In the renal failure simulations, front-loaded regimens at lower exposures (fAUC of 143 mg · h/liter) obtained killing activity similar to that of traditional regimens (fAUC of 268 mg · h/liter), with an ∼97% reduction in the area under the viable count curve over 48 h. In hepatic failure simulations, front-loaded regimens yielded rapid initial killing by up to 7 log10 within 2 h, but considerable regrowth occurred for both front-loaded and traditional regimens. No regimen eradicated the high bacterial inoculum of P. aeruginosa. The current study, which utilizes an in vitro pharmacodynamic infection model, demonstrates the potential benefits of front-loading strategies for polymyxins simulating differential pharmacokinetics in patients with hepatic and renal failure at a range of doses. Our findings may have important clinical implications, as front-loading polymyxins as a part of a combination regimen may be a viable strategy for aggressive treatment of high-bacterial-burden infections.


Assuntos
Antibacterianos/administração & dosagem , Colistina/administração & dosagem , Nefropatias/complicações , Hepatopatias/complicações , Infecções por Pseudomonas/tratamento farmacológico , Antibacterianos/farmacocinética , Antibacterianos/uso terapêutico , Colistina/farmacocinética , Colistina/uso terapêutico , Humanos , Técnicas In Vitro , Nefropatias/metabolismo , Hepatopatias/metabolismo , Modelos Biológicos , Infecções por Pseudomonas/complicações
12.
Drugs R D ; 21(4): 375-384, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34363188

RESUMO

BACKGROUND: Hepatic impairment can impact apixaban pharmacokinetics and pharmacodynamics by decreasing cytochrome P450-mediated metabolism and factor X production. OBJECTIVE: This study evaluated the effect of mild or moderate (Child-Pugh A and B) hepatic impairment on apixaban pharmacokinetics, pharmacodynamics, and safety. METHODS: This open-label, parallel-group, single-dose study included eight mildly and eight moderately hepatically impaired subjects, and 16 healthy subjects. Subjects received a single oral apixaban 5-mg dose (day 1). Pharmacokinetic, pharmacodynamic, and safety assessments were completed at prespecified time points. Apixaban maximum plasma concentration and area under the concentration-time curve to infinity were compared between subjects with hepatic impairment and healthy subjects. RESULTS: Apixaban area under the concentration-time curve to infinity point estimates and 90% confidence intervals were 1.03 (0.80-1.32) and 1.09 (0.85-1.41) for subjects with mild and moderate hepatic impairment vs healthy subjects. Maximum plasma concentration results were similar. Mean (standard deviation) apixaban unbound fraction was 6.8% (1.4), 7.9% (1.8), and 7.1% (1.3) in subjects with mild or moderate hepatic impairment and in healthy subjects. Mean change from baseline in international normalized ratio (3 h post-dose) was 14.7%, 12.7%, and 10.7% for subjects with mild or moderate hepatic impairment and healthy subjects, respectively. A direct relationship was observed between apixaban anti-factor Xa activity and plasma concentration across groups. No serious adverse events or discontinuations due to adverse events occurred. CONCLUSIONS: Mild or moderate hepatic impairment had no clinically relevant impact on apixaban pharmacokinetic or pharmacodynamic measures, suggesting that dose adjustment may not be required.


Assuntos
Fígado , Pirazóis , Piridonas , Administração Oral , Área Sob a Curva , Humanos , Fígado/metabolismo , Hepatopatias/metabolismo
13.
Clin Pharmacol Drug Dev ; 10(9): 974-984, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34342172

RESUMO

This randomized, double-blind, placebo-controlled, ascending single intravenous (IV) bolus-dose study evaluated safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of apixaban, a direct factor Xa (FXa) inhibitor approved for multiple indications. Eight healthy subjects were randomized 3:1 (apixaban:placebo) within each IV dose cohort (0.5, 1.25, 2.5, 3.75, and 5 mg). The 2.5-mg IV panel also received 5 mg of oral apixaban or placebo. Blood samples were collected for PK and PD, including international normalized ratio, modified prothrombin time (mPT), and anti-FXa activity. Apixaban had 66.2% oral bioavailability, dose-proportional exposure, 17 to 26 L steady-state volume of distribution, and 3.2 to 3.5 L/h total plasma clearance. Renal clearance was ≈27%. Anti-FXa activity and mPT changes followed the apixaban plasma concentration-time profile; both were highly correlated with concentration (R2 = 0.99 and R2 = 0.93 for anti-FXa activity and mPT, respectively). International normalized ratio remained within reference range (0.9-1.3). There were no serious or bleeding-related adverse events. Overall, an apixaban single IV bolus was safe and well tolerated over a 10-fold dose range by these subjects. Apixaban had good oral bioavailability, dose-proportional exposure, and constant plasma clearance over a broad dose range, with modest renal clearance. Apixaban PD were consistent with reversible FXa inhibition.


Assuntos
Inibidores do Fator Xa/administração & dosagem , Pirazóis/administração & dosagem , Piridonas/administração & dosagem , Administração Intravenosa , Administração Oral , Adolescente , Adulto , Disponibilidade Biológica , Relação Dose-Resposta a Droga , Método Duplo-Cego , Inibidores do Fator Xa/farmacocinética , Inibidores do Fator Xa/farmacologia , Feminino , Humanos , Coeficiente Internacional Normatizado , Masculino , Tempo de Protrombina , Pirazóis/farmacocinética , Pirazóis/farmacologia , Piridonas/farmacocinética , Piridonas/farmacologia , Distribuição Tecidual , Adulto Jovem
14.
Clin Pharmacokinet ; 58(10): 1265-1279, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31089975

RESUMO

Apixaban is an oral, direct factor Xa inhibitor that inhibits both free and clot-bound factor Xa, and has been approved for clinical use in several thromboembolic disorders, including reduction of stroke risk in non-valvular atrial fibrillation, thromboprophylaxis following hip or knee replacement surgery, the treatment of deep vein thrombosis or pulmonary embolism, and prevention of recurrent deep vein thrombosis and pulmonary embolism. The absolute oral bioavailability of apixaban is ~ 50%. Food does not have a clinically meaningful impact on the bioavailability. Apixaban exposure increases dose proportionally for oral doses up to 10 mg. Apixaban is rapidly absorbed, with maximum concentration occurring 3-4 h after oral administration, and has a half-life of approximately 12 h. Elimination occurs via multiple pathways including metabolism, biliary excretion, and direct intestinal excretion, with approximately 27% of total apixaban clearance occurring via renal excretion. The pharmacokinetics of apixaban are consistent across a broad range of patients, and apixaban has limited clinically relevant interactions with most commonly prescribed medications, allowing for fixed dosages without the need for therapeutic drug monitoring. The pharmacodynamic effect of apixaban is closely correlated with apixaban plasma concentration. This review provides a summary of the pharmacokinetic, pharmacodynamic, biopharmaceutical, and drug-drug interaction profiles of apixaban. Additionally, the population-pharmacokinetic analyses of apixaban in both healthy subjects and in the target patient populations are discussed.


Assuntos
Anticoagulantes/farmacocinética , Pirazóis/farmacocinética , Piridonas/farmacocinética , Animais , Anticoagulantes/efeitos adversos , Anticoagulantes/química , Anticoagulantes/farmacologia , Antídotos/uso terapêutico , Interações Medicamentosas , Humanos , Pirazóis/efeitos adversos , Pirazóis/química , Pirazóis/farmacologia , Piridonas/efeitos adversos , Piridonas/química , Piridonas/farmacologia
15.
Am J Cardiovasc Drugs ; 19(6): 561-567, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31030414

RESUMO

BACKGROUND: This was an open-label, phase I, nonrandomized, single-sequence, crossover study to evaluate the effect of concomitant administration of multiple doses of clarithromycin on the single-dose exposure, safety, and tolerability of apixaban in healthy subjects. METHODS: In total, 19 subjects received a single oral dose of apixaban 10 mg on day 1. On day 4, subjects began receiving oral clarithromycin immediate release (IR) 500 mg twice daily (bid) for 4 days. On day 8, subjects received oral apixaban 10 mg and oral clarithromycin IR 500 mg bid. Oral clarithromycin IR 500 mg bid was given alone on days 9 and 10. RESULTS: Compared with apixaban alone, coadministration of apixaban with clarithromycin resulted in increased apixaban exposure. The adjusted geometric mean ratio (GMR) was 1.299 (90% confidence interval [CI] 1.220-1.384) for peak plasma concentration (Cmax), whereas the adjusted GMR for the area under the concentration curve (AUC(INF)) was 1.595 (90% CI 1.506-1.698). The mean half-life and median time to Cmax of apixaban were comparable with and without concomitant administration of clarithromycin. Administration of apixaban and clarithromycin concomitantly did not result in increased adverse events compared with administration of either agent alone. All adverse events were mild in intensity. CONCLUSIONS: Apixaban Cmax and AUC(INF) increased 30% and 60%, respectively, when multiple doses of clarithromycin were coadministered with apixaban versus administration of apixaban alone. The increase in apixaban Cmax and AUC(INF) with concomitant clarithromycin was less than that which has been observed when apixaban was given with ketoconazole. Administration of apixaban alone and in combination with clarithromycin bid was safe and generally well-tolerated by the healthy adult subjects in this study. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier number NCT02912234.


Assuntos
Claritromicina/farmacologia , Inibidores do Citocromo P-450 CYP3A/farmacologia , Inibidores do Fator Xa/farmacocinética , Pirazóis/farmacocinética , Piridonas/farmacocinética , Adulto , Área Sob a Curva , Estudos Cross-Over , Feminino , Meia-Vida , Voluntários Saudáveis , Humanos , Masculino , Pirazóis/efeitos adversos , Piridonas/efeitos adversos
16.
Bioanalysis ; 8(23): 2429-2443, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27855510

RESUMO

AIM: A UHPLC-MS/MS assay was developed to quantify urinary dehydroepiandrosterone (DHEA), 7ß-hydroxy-DHEA, cortisone and 6ß-hydroxycortisone as potential biomarkers to predict CYP3A activity. RESULTS: A sensitive assay at LLOQ of 0.500 ng/ml with good accuracy and precision was developed for the four analytes in human urine. This UHPLC-MS/MS assay was optimized by eliminating nonspecific loss of the analytes in urine, ensuring complete hydrolysis of the conjugates to unconjugated forms and use of the product ions of [M+H-H2O]+ for multiple reaction monitoring detection of DHEA and 7ß-hydroxy-DHEA. CONCLUSION: This assay was successfully applied to a pilot clinical study. It is also suitable for future drug-drug interaction studies to continue evaluating the potential of these steroids as biomarkers for CYP3A inhibition and induction.


Assuntos
Biomarcadores/urina , Cortisona/urina , Citocromo P-450 CYP3A/metabolismo , Desidroepiandrosterona/urina , Espectrometria de Massas em Tandem , Urinálise/métodos , Cromatografia Líquida de Alta Pressão/normas , Cortisona/metabolismo , Cortisona/normas , Citocromo P-450 CYP3A/química , Desidroepiandrosterona/metabolismo , Desidroepiandrosterona/normas , Interações Medicamentosas , Humanos , Hidroxilação , Limite de Detecção , Extração Líquido-Líquido , Controle de Qualidade , Espectrometria de Massas em Tandem/normas , Urinálise/instrumentação
17.
PLoS One ; 11(6): e0156131, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27284923

RESUMO

Our objective was to study the pharmacodynamics of daptomycin in the presence of varying concentrations of human serum (HS) in vitro to quantify the fraction of daptomycin that is 'active'. Time kill experiments were performed with daptomycin (0 to 256 mg/L) against two MRSA strains at log-phase growth, in the presence of HS (0%, 10%, 30%, 50%, 70%) combined with Mueller-Hinton broth. Daptomycin ≥ 2 mg/L achieved 99.9% kill within 8 h at all HS concentrations; early killing activity was slightly attenuated at higher HS concentrations. After 1 h, bacterial reduction of USA300 upon exposure to daptomycin 4 mg/L ranged from -3.1 to -0.5 log10CFU/mL in the presence of 0% to 70% HS, respectively. Bactericidal activity was achieved against both strains at daptomycin ≥ 4 mg/L for all fractions of HS exposure. A mechanism-based mathematical model (MBM) was developed to estimate the active daptomycin fraction at each %HS, comprising 3 bacterial subpopulations differing in daptomycin susceptibility. Time-kill data were fit with this MBM with excellent precision (r2 >0.95). The active fraction of daptomycin was estimated to range from 34.6% to 25.2% at HS fractions of 10% to 70%, respectively. Despite the reported low unbound fraction of daptomycin, the impact of protein binding on the activity of daptomycin was modest. The active fraction approach can be utilized to design in vitro experiments and to optimize therapeutic regimens of daptomycin in humans.


Assuntos
Antibacterianos/farmacocinética , Daptomicina/farmacocinética , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Antibacterianos/química , Disponibilidade Biológica , Daptomicina/química , Relação Dose-Resposta a Droga , Cálculos da Dosagem de Medicamento , Humanos , Testes de Sensibilidade Microbiana , Modelos Teóricos , Soro/efeitos dos fármacos , Soro/metabolismo , Albumina Sérica/metabolismo , Albumina Sérica/farmacologia
18.
Clin Pharmacokinet ; 51(12): 809-22, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23044523

RESUMO

BACKGROUND AND OBJECTIVES: A previously published study of antiretroviral pharmacokinetics in the female genital tract of HIV-infected women demonstrated differing degrees of female genital tract penetration among antiretrovirals. These blood plasma (BP) and cervicovaginal fluid (CVF) data were co-modelled for four antiretrovirals with varying CVF exposures. METHODS: Six paired BP and CVF samples were collected over 24 h, and antiretroviral concentrations determined using validated liquid chromatography (LC) with UV detection or LC-mass spectrometry analytical methods. For each antiretroviral, a BP model was fit using Bayesian estimation (ADAPT5), followed by addition of a CVF model. The final model was chosen based on graphical and statistical output, and then non-linear mixed-effects modelling using S-ADAPT was performed. Population mean parameters and their variability are reported. Model-predicated area under the concentration-time curve during the dosing interval (AUC(τ)) and exposure ratios of CVF AUC(τ):BP AUC(τ) were calculated for each drug. RESULTS: The base model uses first-order absorption with a lag time, a two-compartment model, and a series of transit compartments that transfer the drug from BP to CVF. Protein-unbound drug transfers into CVF for efavirenz and atazanavir; total drug transfers for lamivudine and tenofovir. CVF follows a one-compartment model for efavirenz and atazanavir, and a two-compartment model for lamivudine and tenofovir. As expected, inter-individual variability was high. Model-predicted CVF AUC(τ):BP AUC(τ) ratios are consistent with published results. CONCLUSIONS: This is the first pharmacokinetic modelling of antiretroviral disposition in BP and CVF. These models will be further refined with tissue data, and used in clinical trials simulations to inform future studies of HIV pre-exposure prophylaxis in women.


Assuntos
Fármacos Anti-HIV/farmacocinética , Genitália Feminina/metabolismo , Modelos Biológicos , Inibidores da Transcriptase Reversa/farmacocinética , Adenina/análogos & derivados , Adenina/sangue , Adenina/farmacocinética , Adulto , Alcinos , Fármacos Anti-HIV/sangue , Sulfato de Atazanavir , Benzoxazinas/sangue , Benzoxazinas/farmacocinética , Ciclopropanos , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/metabolismo , Humanos , Lamivudina/sangue , Lamivudina/farmacocinética , Oligopeptídeos/sangue , Oligopeptídeos/farmacocinética , Organofosfonatos/sangue , Organofosfonatos/farmacocinética , Pré-Menopausa/metabolismo , Piridinas/sangue , Piridinas/farmacocinética , Inibidores da Transcriptase Reversa/sangue , Tenofovir
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