scholarly journals Coadministration of Allopurinol To Increase Antimycobacterial Efficacy of Pyrazinamide as Evaluated in a Whole-Blood Bactericidal Activity Model

2017 ◽  
Vol 61 (10) ◽  
Author(s):  
Claire M. Naftalin ◽  
Rupangi Verma ◽  
Meera Gurumurthy ◽  
Qingshu Lu ◽  
Matthew Zimmerman ◽  
...  

ABSTRACT Coadministering pyrazinamide (PZA) with the xanthine oxidase inhibitor allopurinol increases systemic levels of the active metabolite, pyrazinoic acid (POA), but the effects on bactericidal activity against tuberculosis are unknown. We randomized healthy volunteers to take a single dose of PZA (either 10 or 25 mg/kg of body weight) at the first visit and the same dose 7 days later, coadministered with allopurinol (100 mg daily; 2 days before to 1 day after the PZA dose). Blood was drawn at intervals until 48 h after each PZA dose, and drug levels were measured using liquid chromatography-tandem mass spectrometry. Whole-blood bactericidal activity (WBA) was measured by inoculating blood samples with Mycobacterium tuberculosis and estimating the change in bacterial CFU after 72 h of incubation. Allopurinol increased the POA area under the concentration-time curve from 0 to 8 h (AUC0–8) (18.32 h · μg/ml versus 24.63 h · μg/ml for PZA alone versus PZA plus allopurinol) (P < 0.001) and its peak plasma concentration (C max) (2.81 μg/ml versus 4.00 μg/ml) (P < 0.001). There was no effect of allopurinol on mean cumulative WBA (0.01 ± 0.02 ΔlogCFU versus 0.00 ± 0.02 ΔlogCFU for PZA alone versus PZA plus allopurinol) (P = 0.49). Higher systemic POA levels were associated with greater WBA levels (P < 0.001), but the relationship was evident only at low POA concentrations. The lack of an effect of allopurinol on WBA despite a significant increase in blood POA levels suggests that host-generated POA may be less effective than POA generated inside bacteria. Coadministration of allopurinol does not appear to be a useful strategy for increasing the efficacy of PZA in clinical practice. (This study has been registered at ClinicalTrials.gov under registration no. NCT02700347.)

2018 ◽  
Vol 62 (4) ◽  
pp. e01647-17 ◽  
Author(s):  
Sheng-Hsuan Tseng ◽  
Chuan Poh Lim ◽  
Qi Chen ◽  
Cheng Cai Tang ◽  
Sing Teang Kong ◽  
...  

ABSTRACT Bacterial sepsis is a major cause of morbidity and mortality in neonates, especially those involving methicillin-resistant Staphylococcus aureus (MRSA). Guidelines by the Infectious Diseases Society of America recommend the vancomycin 24-h area under the concentration-time curve to MIC ratio (AUC24/MIC) of >400 as the best predictor of successful treatment against MRSA infections when the MIC is ≤1 mg/liter. The relationship between steady-state vancomycin trough concentrations and AUC24 values (mg·h/liter) has not been studied in an Asian neonatal population. We conducted a retrospective chart review in Singapore hospitals and collected patient characteristics and therapeutic drug monitoring data from neonates on vancomycin therapy over a 5-year period. A one-compartment population pharmacokinetic model was built from the collected data, internally validated, and then used to assess the relationship between steady-state trough concentrations and AUC24. A Monte Carlo simulation sensitivity analysis was also conducted. A total of 76 neonates with 429 vancomycin concentrations were included for analysis. Median (interquartile range) was 30 weeks (28 to 36 weeks) for postmenstrual age (PMA) and 1,043 g (811 to 1,919 g) for weight at the initiation of treatment. Vancomycin clearance was predicted by weight, PMA, and serum creatinine. For MRSA isolates with a vancomycin MIC of ≤1, our major finding was that the minimum steady-state trough concentration range predictive of achieving an AUC24/MIC of >400 was 8 to 8.9 mg/liter. Steady-state troughs within 15 to 20 mg/liter are unlikely to be necessary to achieve an AUC24/MIC of >400, whereas troughs within 10 to 14.9 mg/liter may be more appropriate.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Satoshi Nakano ◽  
Shuhei Osaka ◽  
Yusuke Sabu ◽  
Kei Minowa ◽  
Saeko Hirai ◽  
...  

AbstractProgressive familial intrahepatic cholestasis (PFIC), a rare inherited disorder, progresses to liver failure in childhood. We have shown that sodium 4-phenylbutyrate (NaPB), a drug approved for urea cycle disorders (UCDs), has beneficial effects in PFIC. However, there is little evidence to determine an optimal regimen for NaPB therapy. Herein, a multicenter, open-label, single-dose study was performed to investigate the influence of meal timing on the pharmacokinetics of NaPB. NaPB (150 mg/kg) was administered orally 30 min before, just before, and just after breakfast following overnight fasting. Seven pediatric PFIC patients were enrolled and six completed the study. Compared with postprandial administration, an approved regimen for UCDs, preprandial administration significantly increased the peak plasma concentration and area under the plasma concentration-time curve of 4-phenylbutyrate by 2.5-fold (95% confidential interval (CI), 2.0–3.0;P = 0.003) and 2.4-fold (95% CI, 1.7–3.2;P = 0.005). The observational study over 3 years in two PFIC patients showed that preprandial, but not prandial or postprandial, oral treatment with 500 mg/kg/day NaPB improved liver function tests and clinical symptoms and suppressed the fibrosis progression. No adverse events were observed. Preprandial oral administration of NaPB was needed to maximize its potency in PFIC patients.


Pharmaceutics ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 313 ◽  
Author(s):  
Noriaki Nagai ◽  
Fumihiko Ogata ◽  
Hiroko Otake ◽  
Naohito Kawasaki

Meloxicam (MLX) is widely applied as a therapy for rheumatoid arthritis (RA); however, it takes far too long to reach its peak plasma concentration for a quick onset effect, and gastrointestinal toxicity has been observed in RA patients taking it. To solve these problems, we designed MLX solid nanoparticles (MLX-NPs) by the bead mill method and used them to prepare new oral formulations. The particle size of the MLX-NPs was approximately 20-180 nm, and they remained in the nano-size range for 1 month. The tmax of MLX-NPs was shorter than that of traditional MLX dispersions (MLX-TDs), and the intestinal penetration of MLX-NPs was significantly higher in comparison with MLX-TDs (P < 0.05). Caveolae-dependent endocytosis (CavME), clathrin-dependent endocytosis (CME), and micropinocytosis (MP) were found to be related to the high intestinal penetration of MLX-NPs. The area under the plasma MLX concentration-time curve (AUC) for MLX-NPs was 5-fold higher than that for MLX-TDs (P < 0.05), and the AUC in rats administered 0.05 mg/kg MLX-NPs were similar to rats administered the therapeutic dose of 0.2 mg/kg MLX-TDs. In addition, the anti-inflammatory effect of the MLX-NPs was also significantly higher than that of MLX-TDs at the corresponding dose (P < 0.05), and the therapeutic effect of 0.2 mg/kg MLX-TDs and 0.05 mg/kg MLX-NPs in adjuvant-induced arthritis (AA) rats showed no difference. Furthermore, the gastrointestinal lesions in AA rats treated repetitively with 0.05 mg/kg MLX-NPs were fewer than in rats receiving 0.2 mg/kg MLX-TDs (P < 0.05). In conclusion, we demonstrate that MLX solid nanoparticles allow a quick onset of therapeutic effect and that three endocytosis pathways, CavME, CME, and MP, are related to the high absorption of solid nanoparticles. In addition, we found that MLX solid nanoparticles make it possible to reduce the amount of orally administered drugs, and treatment with low doses of MLX-NPs allows RA therapy without intestinal ulcerogenic responses to MLX. These findings are useful for designing therapies for RA patients.


2019 ◽  
Vol 63 (6) ◽  
Author(s):  
Rajeev Ranjan ◽  
Ashish Srivastava ◽  
Reena Bharti ◽  
Trisha Roy ◽  
Sonia Verma ◽  
...  

ABSTRACT We compared the pharmacokinetics and efficacy of a combination of d-cycloserine (DCS) and ethionamide (ETO) via oral and inhalation routes in mice. The plasma half-life (t1/2) of oral ETO at a human-equivalent dose decreased from 4.63 ± 0.61 h to 1.64 ± 0.40 h when DCS was coadministered. The area under the concentration-time curve from 0 h to time t (AUC0–t) was reduced to one-third. Inhalation overcame the interaction. Inhalation, but not oral doses, reduced the lung CFU/g of Mycobacterium tuberculosis H37Rv from 6 to 3 log10 in 4 weeks, indicating bactericidal activity.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 782
Author(s):  
Ji-Min Kim ◽  
Seong-Wook Seo ◽  
Dong-Gyun Han ◽  
Hwayoung Yun ◽  
In-Soo Yoon

Repaglinide (RPG), a rapid-acting meglitinide analog, is an oral hypoglycemic agent for patients with type 2 diabetes mellitus. Quercetin (QCT) is a well-known antioxidant and antidiabetic flavonoid that has been used as an important ingredient in many functional foods and complementary medicines. This study aimed to comprehensively investigate the effects of QCT on the metabolism of RPG and its underlying mechanisms. The mean (range) IC50 of QCT on the microsomal metabolism of RPG was estimated to be 16.7 (13.0–18.6) μM in the rat liver microsome (RLM) and 3.0 (1.53–5.44) μM in the human liver microsome (HLM). The type of inhibition exhibited by QCT on RPG metabolism was determined to be a mixed inhibition with a Ki of 72.0 μM in RLM and 24.2 μM in HLM as obtained through relevant graphical and enzyme inhibition model-based analyses. Furthermore, the area under the plasma concentration versus time curve (AUC) and peak plasma concentration (Cmax) of RPG administered intravenously and orally in rats were significantly increased by 1.83- and 1.88-fold, respectively, after concurrent administration with QCT. As the protein binding and blood distribution of RPG were observed to be unaltered by QCT, it is plausible that the hepatic first-pass and systemic metabolism of RPG could have been inhibited by QCT, resulting in the increased systemic exposure (AUC and Cmax) of RPG. These results suggest that there is a possibility that clinically significant pharmacokinetic interactions between QCT and RPG could occur, depending on the extent and duration of QCT intake from foods and dietary supplements.


Author(s):  
V. A. Chernyshov

The article summarizes mechanisms, linking hyperuricemia, the elevated serum levels of uric acid (UA), and atrial fibrillation (AF), the most frequent cardiac arrhythmia. The actuality of the problem is explained by the fact that UA is considered as an independent risk marker of AF closely associated with the onset and subsequent persistence of AF as well as by the AF increased risk in males and females with hyperuricemia. It has been shown how hyperuricemia, combined with other AF risk factors, contributeы to the development of arrhythmia, as well as the role of hyperuricemia, oxidative stress and renin‑angiotensin system (RAS) activation in the AF pathogenesis. The consideration have been given to the hyperuricemia association with a prevalence of AF among the patients with carbohydrate exchange disorders such as metabolic syndrome and type 2 diabetes mellitus as well as to the relationship between hyperuricemia and endothelial vascular dysfunction, oxidative stress, high blood concentration of systemic inflammatory markers and insulin resistance (IR). Some mechanisms of hyperuricemia participation in cardiac remodeling as a risk factor of AF are adduced. In particular, the relationship between hyperuricemia and left atrial (LA) size that could be mediated through systemic inflammation and IR is discussed. A significance of a direct impaired action of UA on LA cardiomyocytes resulted in their structural and ionic remodeling is shown. The role of xanthinoxidase (XO) activation in initiation of oxidative stress and inflammation in cardiomyocytes and endothelial cells is discussed. All these mechanisms are emphasized to be able to shorten a potential of action of atrial cardiomyocytes as well as to reduce a threshold of re‑entry mechanism initiation and to promote an appearance of the first and the following AF episodes. An important place in the review is taken for an intracellular UA and its cellular transporters in the context of their participation in pathogenesis of AF. The possibilities of drug hyperuricemia correction have been described in regards the reduction of AF risk, in particular, the role of reducing of the oxidative stress intensity with the use of xanthine oxidase inhibitor allopurinol, the inhibitor of NADPH oxidase apocynin, the antioxidant N‑acetylcysteine in the reduction of the risk of onset and subsequent recurrences of AF episodes, and transition of arrhythmia in the persistent form. Some perspectives of probenecid (an inhibitor of UA intracellular transporter activity) usage in the reduction of AF risk due to such of its mechanisms as a reduction of intracellular UA accumulation and antiapoptotic action as well as an ability of this agent to inhibit a locally activated oxidative stress and locally activated tissue RAS are discussed. A significance of the further detailed study of pathophysiological mechanisms of AF in hyperuricemia is emphasized for elaboration of the most effective practical recommendations in prevention of this arrhythmia in persons with UA exchange disorders.


2018 ◽  
Vol 62 (4) ◽  
Author(s):  
Christopher M. Rubino ◽  
Sujata M. Bhavnani ◽  
Jeffery S. Loutit ◽  
Elizabeth E. Morgan ◽  
Dan White ◽  
...  

ABSTRACTMeropenem-vaborbactam is a fixed combination of the novel β-lactamase inhibitor vaborbactam and the carbapenem antibiotic meropenem, developed for the treatment of serious infections caused by drug-resistant Gram-negative bacteria. The safety, tolerability, and pharmacokinetics (PK) of vaborbactam and meropenem following single and multiple ascending doses of each study drug administered alone or combined were evaluated in 76 healthy adult subjects in a randomized, placebo-controlled, double-blind study. Subjects were enrolled in 1 of 5 dose cohorts (receiving 250 to 2,000 mg vaborbactam and/or 1,000 to 2,000 mg meropenem) alone or in combination. No subjects discontinued the study due to adverse events (AEs), and no serious AEs were observed. The pharmacokinetics of meropenem and vaborbactam were similar when given alone or in combination; all evaluated plasma PK exposure measures (peak plasma concentration, area under the plasma concentration-time curve [AUC] from time zero to the last measurable concentration area under the plasma concentration-time curve, and AUC from time zero to infinity) were similar for the study drugs alone versus those in combination, indicating no pharmacokinetic interaction between meropenem and vaborbactam. Across all treatments, 47 to 64% of an administered meropenem dose and 75 to 95% of vaborbactam was excreted unchanged in the urine over 48 h postdose. Meropenem and vaborbactam, when given alone or in combination, have similar pharmacokinetic properties, with no plasma or urine PK drug-drug interactions, and are well tolerated. These findings supported further clinical investigation of the combination product. (This study is registered at ClinicalTrials.gov under registration no. NCT01897779.)


Author(s):  
GNANASEKARAN JOHN SELVARAJ ◽  
ARUL BALASUBRAMANIAN ◽  
KOTHAI RAMALINGAM

Objective: The present study was aimed to alter the pharmacokinetic parameters of the drug pentoxifylline using a novel natural mucoadhesive polymer from two different plants, Manilkara zapotta Linn and Ocimum basilicum Linn. Methods: The polymer was isolated and six batches of mucoadhesive tablets of pentoxifylline was formulated with 3 different concentrations of each polymer. The best formulation from each of the polymer was selected and administered to rabbits and the plasma drug concentration was compared with the marketed formulation. The pharmacokinetic parameters such as such as Cmax, tmax, AUC, AUMC, λz, t1/2, and MRT were determined. Results: The plasma drug concentration vs time curve shows the extended-release of pentoxifylline when compared with the conventional marketed formulation. The results show that there is no change in the peak plasma concentration, but the significant difference was observed in t½, which showed approximately 2.5 fold increase from 2.44 to 6.87 h and the AUC showed five-fold increase from 22.40 to 117.19 μg*h/ml, and other pharmacokinetic parameters, when compared with the marketed formulation. Conclusion: The isolated polymer from the plants Manilkara zapotta Linn. and Ocimum basilicum Linn can be used as a carrier for developing mucoadhesive formulations and it alter the pharmacokinetic of pentoxifylline positively.


2018 ◽  
Vol 62 (6) ◽  
Author(s):  
Ilya Nikolaevich Zykov ◽  
Ørjan Samuelsen ◽  
Lotte Jakobsen ◽  
Lars Småbrekke ◽  
Dan I. Andersson ◽  
...  

ABSTRACTFosfomycin has become an attractive treatment alternative for urinary tract infections (UTIs) due to increasing multidrug resistance (MDR) inEscherichia coli. In this study, we evaluated the pharmacokinetic (PK) and pharmacodynamic (PD) indices of fosfomycin and itsin vivoactivity in an experimental murine model of ascending UTI. Subcutaneous administration of fosfomycin showed that the mean peak plasma concentrations of fosfomycin were 36, 280, and 750 mg/liter following administration of a single dose of 0.75, 7.5, and 30 mg/mouse, respectively, with an elimination half-life of 28 min, and urine peak concentrations of 1,100, 33,400, and 70,000 mg/liter expected to be sustained above 1 mg/liter (MIC of the test strain, NU14) for 5, 8, and 9.5 h, respectively. The optimal PK/PD indices for reducing urine colony counts (number of CFU per milliliter) were determined to be the area under the concentration-time curve/MIC from 0 to 72 h and the maximum concentration/MIC on the basis of the dose-dependent bloodstream PK and the results of an evaluation of six dosing regimens. With a dosing regimen of 15 mg/mouse twice (every 36 h), fosfomycin significantly reduced the number of CFU per milliliter of all susceptible strains in urine, including clinical MDR strains, except for one clinical strain (P= 0.062). Variable degrees of reduction were observed in the bladder and kidneys. No significant reductions in the number of CFU per milliliter were observed with the resistant strains. In conclusion, fosfomycin shows concentration-dependentin vivoactivity, and the results suggest that fosfomycin is an effective alternative to carbapenems in treating MDRE. coliin uncomplicated UTIs. The data on the effectiveness of fosfomycin against the MDR isolates along with the results of PK/PD modeling should facilitate the further development of improved recommendations for its clinical use.


2016 ◽  
Vol 61 (3) ◽  
Author(s):  
María del Mar Castro ◽  
Maria Adelaida Gomez ◽  
Anke E. Kip ◽  
Alexandra Cossio ◽  
Eduardo Ortiz ◽  
...  

ABSTRACT An open-label pharmacokinetics (PK) clinical trial was conducted to comparatively assess the PK and explore the pharmacodynamics (PD) of miltefosine in children and adults with cutaneous leishmaniasis (CL) in Colombia. Sixty patients, 30 children aged 2 to 12 years and 30 adults aged 18 to 60 years, were enrolled. Participants received miltefosine (Impavido) at a nominal dose of 2.5 mg/kg/day for 28 days. Miltefosine concentrations were measured in plasma and peripheral blood mononuclear cells by liquid chromatography-tandem mass spectrometry of samples obtained during treatment and up to 6 months following completion of treatment, when therapeutic outcome was determined. Fifty-two patients were cured, 5 pediatric patients failed treatment, and 3 participants were lost to follow-up. Leishmania (Viannia) panamensis predominated among the strains isolated (42/46; 91%). Noncompartmental analysis demonstrated that plasma and intracellular miltefosine concentrations were, overall, lower in children than in adults. Exposure to miltefosine, estimated by area under the concentration-time curve and maximum concentration, was significantly lower in children in both the central and intracellular compartments (P < 0.01). Leishmania persistence was detected in 43% of study participants at the end of treatment and in 27% at 90 days after initiation of treatment. Clinical response was not dependent on parasite elimination. In vitro miltefosine susceptibility was similar for Leishmania strains from adults and children. Our results document PK differences for miltefosine in children and adults with cutaneous leishmaniasis that affect drug exposure and could influence the outcome of treatment, and they provide bases for optimizing therapeutic regimens for CL in pediatric populations. (This study has been registered at ClinicalTrials.gov under identifier NCT01462500.)


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