scholarly journals Pharmacokinetic Interaction between Zidovudine and Trimethoprim/sulphamethoxazole in HIV-1 Infected Children

2000 ◽  
Vol 11 (5) ◽  
pp. 254-258 ◽  
Author(s):  
Shannon Dallas ◽  
Stanley E Read ◽  
Susan King ◽  
Gideon Koren ◽  
Reina Bendayan
Keyword(s):  
Half Life ◽  
Statistical Significance ◽  
Pharmacokinetic Interaction ◽  
Pharmacokinetic Analysis ◽  
Pharmacokinetic Parameters ◽  
Open Label ◽  
Time Curve ◽  
Number Of Patients ◽  
Glucuronide Metabolite ◽  
Hiv 1

OBJECTIVE: To evaluate the effect of the antimicrobial agent trimethoprim/sulphamethoxazole (TMP/SMX) on the pharmacokinetic properties of the antiretroviral drug zidovudine (ZDV).DESIGN: This single dose, open label, crossover study involved the oral administration of ZDV (150 mg/m2) alone and in combination with oral TMP/SMX (2.5 mg/kg) on two separate occasions. Serial blood samples (0 to 8 h) were collected, and concentrations of ZDV and its glucuronide metabolite were quantified using a radioimmunoassay. ZDV pharmacokinetics were determined by noncompartmental analysis.PATIENTS AND SETTING: Six HIV-1 infected children aged four months to five years were recruited from the HIV clinic at The Hospital for Sick Children, Toronto, Ontario. Only three patients completed both study phases and were included in the pharmacokinetic analysis.MAIN RESULTS: With TMP/SMX therapy, no statistically significant changes were observed in ZDV pharmacokinetic parameters. However, there was a trend towards increased ZDV half-life and area under the concentration versus time curve, as well as decreased apparent oral clearance. Similarly, a trend towards an increased half-life of the ZDV-glucuronide metabolite was also observed.CONCLUSION: The changes in ZDV pharmacokinetics in the presence of TMP/SMX did not reach statistical significance, most likely due to the limited number of patients involved. Despite the limited data, a possible interaction between ZDV and TMP/SMX in young HIV-1 infected children should be considered, and patients may require close clinical monitoring.

Pharmacokinetic analyses of vorinostat in patients with metastatic soft tissue sarcoma.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 10041-10041 ◽  
Author(s):  
Thomas Schmitt ◽  
Bianca Andres ◽  
Lu Liu ◽  
Margarete Leisen ◽  
Anthony D Ho ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Soft Tissue Sarcoma ◽  
Half Life ◽  
Mononuclear Cells ◽  
Statistical Significance ◽  
Rank Test ◽  
Open Label ◽  
Time Curve ◽  
Peripheral Blood Mononuclear ◽  
Metastatic Soft Tissue Sarcoma

10041^ Background: New treatment options for patients with metastatic soft tissue sarcoma (STS) are urgently needed. Preclinical studies suggest activity of vorinostat (V), a histone desacetylase (HDAC) inhibitor, in STS. Methods: We initiated a multicenter, open-label, non-randomized phase II trial (SAHA-I, NCT00918489) to investigate efficacy and safety of V in patients with metastatic STS failing 1°-line anthracycline-based CTX. Patients were treated with V 400 mg po QD for 28 days followed by a therapy-free period of 7 days. Blood samples for pharmacokinetic (PK) analyses were collected on day 7 of treatment cycle 1. Samples were acquired before and 30, 60, 90, 120, 240, 360, and 480 minutes after oral administration of V. Plasma- and intracellular concentration of V in peripheral blood mononuclear cells (PBMCs) was determined by mass spectrometry. Statistical differences were assessed by Wilcoxon matched-pairs signed rank test. This trial is ongoing. Results: Data on PK was available for n=8 subjects (male=4, female=4, median age=62 years). In plasma samples, mean Cmax (maximum concentration), tmax (time to reach max. concentration), AUC (area under the plasma-concentration time curve), t1/2 (elimination half-life) and Cl/F (apparent total clearance) were 350 ng/mL, 101 min, 71.1 min*µg/mL, 103 min and 5903 mL/min. The corresponding parameters in PBMCs were 558 ng/mL, 97.5 min, 208.4 min*µg/mL, 286 min and 2475 mL/min, respectively.The AUC plasma/PBMC ratio was 2.93, indicating accumulation of V in PBMCs. Differences in AUC (p=.008) and t1/2 (p=.01) reached statistical significance. Conclusions: Interestingly, significantly higher concentrations of V were achieved in PBMCs andelimination half-life was prolonged compared to plasma. These results suggest potent intracellular activity of V.

An Evaluation of the Potential for Pharmacokinetic Interaction between Tramadol and Cytochrome P450 2D6 Inhibitor Promethazine

2014 ◽  
Vol 989-994 ◽  
pp. 1041-1043
Author(s):  
Ping Liu ◽  
Liang Sun ◽  
Jian Zhang ◽  
Rui Chen Guo
Keyword(s):  
Single Dose ◽  
Plasma Concentration ◽  
Pharmacokinetic Interaction ◽  
Apparent Volume ◽  
Volume Of Distribution ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Open Label ◽  
Tramadol Hydrochloride ◽  
Time Curve

In this single-center, randomized, open-label, 3-way crossover study, subjects received each of the following: a single dose of Tramadol Hydrochloride Injection (THI) 35 mg, a single dose of Promethazine Hydrochloride Injection (PHI) 45 mg, and single dose of Compound Tramadol Hydrochloride Injection (CTHI) 80mg. Blood was collected and plasma was analyzed for the pharmacokinetic parameters (maximum plasma concentration [Cmax], time to Cmax [Tmax], area under the plasma concentration-time curve, plasma elimination half-life, clearance, and apparent volume of distribution) of Tramadol and Promethazine. In general, several pharmacokinetic interactions were observed between Tramadol and Promethazine in the present study.

scholarly journals Pharmacokinetic Interaction between Fosamprenavir-Ritonavir and Rifabutin in Healthy Subjects

2007 ◽  
Vol 52 (2) ◽  
pp. 534-538 ◽  
Author(s):  
Susan L. Ford ◽  
Ya-Chi Chen ◽  
Yu Lou ◽  
Julie Borland ◽  
Sherene S. Min ◽  
...  
Keyword(s):  
Steady State ◽  
Systemic Exposure ◽  
Pharmacokinetic Interaction ◽  
Concomitant Administration ◽  
Pharmacokinetic Parameters ◽  
Phosphate Ester ◽  
Open Label ◽  
Time Curve ◽  
Dosing Interval ◽  
Cyp3a4 Inhibitors

ABSTRACT Rifabutin (RFB) is administered for treatment of tuberculosis and Mycobacterium avium complex infection, including use for patients coinfected with human immunodeficiency virus (HIV). Increased systemic exposure to RFB and its equipotent active metabolite, 25-O-desacetyl-RFB (dAc-RFB), has been reported during concomitant administration of CYP3A4 inhibitors, including ritonavir (RTV), lopinavir, and amprenavir (APV); therefore, a reduction in the RFB dosage is recommended when it is coadministered with these protease inhibitors. Fosamprenavir (FPV), the phosphate ester prodrug of the HIV type 1 protease inhibitor APV, is administered either with or without RTV. A randomized, open-label, two-period, two-sequence, balanced, crossover drug interaction study was conducted with 22 healthy adult subjects to compare steady-state plasma RFB pharmacokinetic parameters during concomitant administration of FPV-RTV (700/100 mg twice a day [BID]) with a 75%-reduced RFB dose (150 mg every other day [QOD]) to the standard RFB regimen (300 mg once per day [QD]) by geometric least-squares mean ratios. Relative to results with RFB (300 mg QD), coadministration of dose-adjusted RFB with FPV-RTV resulted in an unchanged RFB area under the concentration-time curve for 0 to 48 h (AUC0-48) and a 14% decrease in the maximum concentration of drug in plasma (C max), whereas the AUC0-48 and C max of dAc-RFB were increased by 11- and 6-fold, respectively, resulting in a 64% increase in the total antimycobacterial AUC0-48. Relative to historical controls, the plasma APV AUC from 0 h to the end of the dosing interval (AUC0-τ) and C max were increased ∼35%, and the concentration at the end of the dosing interval at steady state was unchanged following coadministration of RFB with FPV-RTV. The safety profile of the combination of RFB and FPV-RTV was consistent with previously described events with RFB or FPV-RTV alone. Based on the results of this study, a reduction in the RFB dose by ≥75% (to 150 mg QOD or three times per week) is recommended when it is coadministered with FPV-RTV (700/100 mg BID).

scholarly journals Herb-Drug Interaction betweenEchinacea purpureaand Darunavir-Ritonavir in HIV-Infected Patients

2010 ◽  
Vol 55 (1) ◽  
pp. 326-330 ◽  
Author(s):  
José Moltó ◽  
Marta Valle ◽  
Cristina Miranda ◽  
Samandhy Cedeño ◽  
Eugenia Negredo ◽  
...  
Keyword(s):  
High Performance ◽  
Geometric Mean ◽  
Echinacea Purpurea ◽  
The Body ◽  
Pharmacokinetic Parameters ◽  
Root Extract ◽  
Open Label ◽  
Fixed Sequence ◽  
Time Curve ◽  
Sequence Study

ABSTRACTThe aim of this open-label, fixed-sequence study was to investigate the potential ofEchinacea purpurea, a commonly used botanical supplement, to interact with the boosted protease inhibitor darunavir-ritonavir. Fifteen HIV-infected patients receiving antiretroviral therapy including darunavir-ritonavir (600/100 mg twice daily) for at least 4 weeks were included.E. purpurearoot extract capsules were added to the antiretroviral treatment (500 mg every 6 h) from days 1 to 14. Darunavir concentrations in plasma were determined by high-performance liquid chromatography immediately before and 1, 2, 4, 6, 8, 10, and 12 h after a morning dose of darunavir-ritonavir on days 0 (darunavir-ritonavir) and 14 (darunavir-ritonavir plus echinacea). Individual darunavir pharmacokinetic parameters were calculated by noncompartmental analysis and compared between days 0 and 14 with the geometric mean ratio (GMR) and its 90% confidence interval (CI). The median age was 49 (range, 43 to 67) years, and the body mass index was 24.2 (range, 18.7 to 27.5) kg/m2. Echinacea was well tolerated, and all participants completed the study. The GMR for darunavir coadministered with echinacea relative to that for darunavir alone was 0.84 (90% CI, 0.63-1.12) for the concentration at the end of the dosing interval, 0.90 (90% CI, 0.74-1.10) for the area under the concentration-time curve from 0 to 12 h, and 0.98 (90% CI, 0.82-1.16) for the maximum concentration. In summary, coadministration ofE. purpureawith darunavir-ritonavir was safe and well tolerated. Individual patients did show a decrease in darunavir concentrations, although this did not affect the overall darunavir or ritonavir pharmacokinetics. Although no dose adjustment is required, monitoring darunavir concentrations on an individual basis may give reassurance in this setting.

Withdrawal of cefoperazone with milk after intramammary administration in dairy cows – prospective and retrospective analysis

2017 ◽  
Vol 20 (2) ◽  
pp. 261-268
Author(s):  
A. Burmańczuk ◽  
T. Grabowski ◽  
T. Błądek ◽  
C. Kowalski ◽  
P. Dębiak
Keyword(s):  
Dairy Cows ◽  
Half Life ◽  
Drug Distribution ◽  
Compartment Model ◽  
Clinical Mastitis ◽  
Pharmacokinetic Analysis ◽  
Pharmacokinetic Parameters ◽  
Lactation Period ◽  
Milk Samples ◽  
Drug Concentrations

Abstract The aim of the study was to carry out retrospective and prospective comparative analyses of the pharmacokinetics of CEF after single intramammary (IMM) administration in cows. The prospective study (study A) was conducted on 9 dairy cows of the Polish Black-White race with clinical mastitis during the lactation period. Milk samples were collected at 2, 4, 6, 8, 10, 24, 36, 48, 72 and 84 h after single IMM administration of 250 mg of CEF to one quarter. Drug concentrations in milk samples were determined by HPLC-MS/MS technique and the results of the pharmacokinetic analysis were compared to those obtained in previous studies based on the microbiological (study B) and HPLC-UV methods (study C and D). Pharmacokinetic parameters were calculated based on adapted two-compartment model of drug distribution. One of the findings of the comparison of the analysed investigations is that the CEF kinetics determined with the microbiological method is consistent with the results obtained by the authors of this paper. Both studies yielded similar results of the key pharmacokinetic parameters related to the level of the drug distribution to tissues and elimination half-life. In the pharmacodynamic analysis, the observations in all four studies were entirely consistent and have shown lower values of T>MIC90 in healthy animals and significantly higher values in infected dairy cows. The comparison of studies A, B, C, and D revealed that the time of complete CEF wash-out of 90.90% varied and amounted to 5.7, 8.0, 2.2, and 2.2 days after administration of the drug, respectively. It was confirmed that not only the type of the analytical method but also correct sampling have a significant impact on determination of the correct value of the drug half-life after IMM administration. The comparative analysis of studies in which the milk yield was high and low allows a conclusion that this parameter in the case of CEF has no significant effect on T>MIC90.

scholarly journals Safety, toleration, and pharmacokinetics of intravenous azithromycin.

1996 ◽  
Vol 40 (11) ◽  
pp. 2577-2581 ◽  
Author(s):  
D R Luke ◽  
G Foulds ◽  
S F Cohen ◽  
B Levy
Keyword(s):  
Half Life ◽  
Active Drug ◽  
Slow Release ◽  
Volume Of Distribution ◽  
Pharmacokinetic Parameters ◽  
Time Curve ◽  
Concentration Time ◽  
Elimination Half ◽  
The Mean ◽  
Male Subjects

To date, the clinical pharmacology of large intravenous doses of azithromycin has not been described. In the present study, single 2-h intravenous infusions of 1, 2, and 4 g of azithromycin were administered to three parallel groups (in each group, six received active drug and two received placebo) of healthy male subjects. Toleration (assessed by scores of subject-administered visual analog scale tests spanning 0 [good] to 10 [poor]), safety, pharmacokinetics, and serum motilin levels were monitored for up to 240 h after the start of each intravenous infusion. Mean nausea scores of 0.0, 0.0, 1.0, and 0.5 and abdominal cramping scores of 0.0, 0.0, 0.4, and 0.4 for 12-h periods after doses of 0, 1, 2, and 4 g of azithromycin, respectively, suggested that azithromycin was well tolerated. Because of the standardized 1-mg/ml infusates, all subjects in the 4-g dosing group complained of an urgent need to urinate. There were no consistent trends in endogenous motilin levels throughout the study. The maximum concentration of azithromycin in serum (10 micrograms/ml after a 4-g dose) and the area under the concentration-time curve (82 micrograms.h/ml after a 4-g dose) were dose related. The mean pharmacokinetic parameters were an elimination half-life of 69 h, total systemic clearance of 10 ml/min/kg, and a volume of distribution at steady state of 33.3 liters/kg. The pharmacokinetic results suggest that the long half-life of azithromycin is due to extensive uptake and slow release of the drug from tissues rather than an inability to clear the drug. Single intravenous doses of up to 4 g of azithromycin in healthy subjects are generally well tolerated, and quantifiable concentrations may persist in serum for 10 days or more.

scholarly journals Lack of Effect of Zafirlukast on the Pharmacokinetics of Azithromycin, Clarithromycin, and 14-Hydroxyclarithromycin in Healthy Volunteers

1999 ◽  
Vol 43 (5) ◽  
pp. 1152-1155 ◽  
Author(s):  
Kevin W. Garey ◽  
Charles A. Peloquin ◽  
Paul G. Godo ◽  
Anne N. Nafziger ◽  
Guy W. Amsden
Keyword(s):  
Steady State ◽  
Healthy Subjects ◽  
High Performance ◽  
Pharmacokinetic Parameters ◽  
Steady State Concentration ◽  
Open Label ◽  
Time Curve ◽  
Data Analyses ◽  
Concentration Time ◽  
State Concentration

ABSTRACT This randomized, open-label, crossover study was conducted to investigate whether the coadministration of zafirlukast would affect the pharmacokinetics of azithromycin, clarithromycin, or 14-hydroxyclarithromycin (14-OHC). Twelve healthy subjects (six males and six females) received single 500-mg doses of azithromycin and clarithromycin with and without zafirlukast given to a steady-state concentration. Blood was collected prior to all macrolide doses and for 3 and 10 days after each clarithromycin and azithromycin dose, respectively. Serum was assayed for azithromycin, clarithromycin, and 14-OHC concentrations by validated high-performance liquid chromatography assay systems. Data analyses were done by noncompartmental and nonparametric methods. Analysis of the patients indicated that the addition of steady-state concentrations of zafirlukast did not significantly alter the pharmacokinetic parameters of or overall exposure (based on the area under the concentration-time curve) to azithromycin, clarithromycin, and 14-OHC. While zafirlukast is a known inhibitor of CYP3A4, it does not appear to exert a clinically or statistically significant pharmacokinetic effect on azithromycin, clarithromycin, or 14-OHC.

scholarly journals Effects of Valproic Acid Coadministration on Plasma Efavirenz and Lopinavir Concentrations in Human Immunodeficiency Virus-Infected Adults

2004 ◽  
Vol 48 (11) ◽  
pp. 4328-4331 ◽  
Author(s):  
Robert DiCenzo ◽  
Derick Peterson ◽  
Kim Cruttenden ◽  
Gene Morse ◽  
Garret Riggs ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Valproic Acid ◽  
Geometric Mean ◽  
Pharmacokinetic Parameters ◽  
Time Curve ◽  
Blood Samples ◽  
Immunodeficiency Virus ◽  
Before And After ◽  
Trough Concentrations ◽  
Hiv 1

ABSTRACT Valproic acid (VPA) has the potential to benefit patients suffering from human immunodeficiency virus (HIV)-associated cognitive impairment. The purpose of this study was to determine if VPA affects the plasma concentration of efavirenz (EFV) or lopinavir. HIV type 1 (HIV-1)-infected patients receiving EFV or lopinavir-ritonavir (LPV/r) had 9 or 10 blood samples drawn over 8 to 24 h of a dosing interval at steady state before and after receiving 250 mg of VPA twice daily for 7 days. VPA blood samples drawn before (C 0) and 8 h after the morning dose (8 h) were compared to blood samples from a group of HIV-1-infected subjects who were taking either combined nucleoside reverse transcriptase inhibitors alone or had discontinued antiretroviral therapy. Pharmacokinetic parameters were calculated by noncompartmental analysis, and tests of bioequivalence were based on 90% confidence intervals (CIs) for ratios or differences. The geometric mean ratio (GMR) (90% CI) of the areas under the concentration-time curve from 0 to 24 h (AUC0-24s) of EFV (n = 11) with and without VPA was 1.00 (0.85, 1.17). The GMR (90% CI) of the AUC0-8s of LPV (n = 8) with and without VPA was 1.38 (0.98, 1.94). The differences (90% CI) in mean C 0 and 8-h VPA concentrations versus the control (n = 11) were −1.0 (−9.4, 7.4) μg/ml and −2.1 (−11.1, 6.9) μg/ml for EFV (n = 10) and −5.0 (−13.2, 3.3) μg/ml and −6.7 (−17.6, 4.2) μg/ml for LPV/r (n = 11), respectively. EFV administration alone is bioequivalent to EFV and VPA coadministration. LPV concentrations tended to be higher when the drug was combined with VPA. Results of VPA comparisons fail to raise concern that coadministration with EFV or LPV/r will significantly influence trough concentrations of VPA.

scholarly journals Paritaprevir and Ritonavir Liver Concentrations in Rats as Assessed by Different Liver Sampling Techniques

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Charles S. Venuto ◽  
Marianthi Markatou ◽  
Yvonne Woolwine-Cunningham ◽  
Rosemary Furlage ◽  
Andrew J. Ocque ◽  
...  
Keyword(s):  
Surgical Resection ◽  
Needle Aspiration ◽  
Pharmacokinetic Analysis ◽  
Pharmacokinetic Parameters ◽  
Sprague Dawley ◽  
Time Curve ◽  
Tissue Samples ◽  
Drug Concentrations ◽  
Sprague Dawley Rats ◽  
Liquid Chromatography Tandem Mass

ABSTRACT The liver is crucial to pharmacology, yet substantial knowledge gaps exist in the understanding of its basic pharmacologic processes. An improved understanding for humans requires reliable and reproducible liver sampling methods. We compared liver concentrations of paritaprevir and ritonavir in rats by using samples collected by fine-needle aspiration (FNA), core needle biopsy (CNB), and surgical resection. Thirteen Sprague-Dawley rats were evaluated, nine of which received paritaprevir/ritonavir at 30/20 mg/kg of body weight by oral gavage daily for 4 or 5 days. Drug concentrations were measured using liquid chromatography-tandem mass spectrometry on samples collected via FNA (21G needle) with 1, 3, or 5 passes (FNA1, FNA3, and FNA5); via CNB (16G needle); and via surgical resection. Drug concentrations in plasma were also assessed. Analyses included noncompartmental pharmacokinetic analysis and use of Bland-Altman techniques. All liver tissue samples had higher paritaprevir and ritonavir concentrations than those in plasma. Resected samples, considered the benchmark measure, resulted in estimations of the highest values for the pharmacokinetic parameters of exposure (maximum concentration of drug in serum [C max] and area under the concentration-time curve from 0 to 24 h [AUC0–24]) for paritaprevir and ritonavir. Bland-Altman analyses showed that the best agreement occurred between tissue resection and CNB, with 15% bias, followed by FNA3 and FNA5, with 18% bias, and FNA1 and FNA3, with a 22% bias for paritaprevir. Paritaprevir and ritonavir are highly concentrated in rat liver. Further research is needed to validate FNA sampling for humans, with the possible derivation and application of correction factors for drug concentration measurements.

Effect of the Addition of Ciprofloxacin on Theophylline Pharmacokinetics in Subjects Inhibited by Cimetidine

1992 ◽  
Vol 26 (1) ◽  
pp. 11-13 ◽  
Author(s):  
Robin L. Davis ◽  
Ronald W. Quenzer ◽  
H. William Kelly ◽  
J. Robert Powell
Keyword(s):  
Half Life ◽  
Repeated Measures ◽  
Enzyme Inhibitors ◽  
Enzyme Inhibitor ◽  
Combined Treatment ◽  
Pharmacokinetic Analysis ◽  
Pharmacokinetic Parameters ◽  
Microsomal Enzyme ◽  
Elimination Half Life ◽  
Elimination Half

OBJECTIVE: Although the effect of individual enzyme inhibitors on hepatic microsomal enzyme activity has been studied extensively, little data exist on the effects of combinations of inhibiting agents. The purpose of this study was to investigate the effect of the addition of a second hepatic oxidative enzyme inhibitor on the inhibition of metabolism in subjects already maximally inhibited by cimetidine. Ciprofloxacin was used as the second inhibitor. DESIGN: In a randomized crossover sequence, subjects received theophylline 5 mg/kg on day 6 of therapy with cimetidine 2400 mg/d, ciprofloxacin 1 g/d, both drugs, or while drug-free. SETTING: National Institutes of Health-funded General Clinical Research Center. PARTICIPANTS: Eight normal volunteers (6 men, 2 women; mean age 25.2 y). OUTCOME MEASURES: Theophylline pharmacokinetic parameters after each treatment were determined by model independent pharmacokinetic analysis. Statistical analysis of the data for differences between treatments was assessed by ANOVA for repeated measures. RESEARCH: When administered alone, ciprofloxacin and cimetidine caused a significant increase in theophylline elimination half-life and a decrease in clearance. Theophylline elimination half-life was significantly longer during combined therapy compared with either drug alone. Theophylline clearance was lower during combined treatment, although this relationship did not reach statistical significance. CONCLUSIONS: The addition of a second enzyme inhibitor in subjects receiving maximally inhibiting doses of cimetidine can produce a further decrease in the hepatic metabolism of drugs that are metabolized by the cytochrome P-450 microsomal enzyme system. As cimetidine and ciprofloxacin are frequently used together for a variety of common clinical indications, clinicians should be aware of this drug interaction and should consider that a similar effect may occur when other enzyme inhibitors are used concomitantly.

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