scholarly journals Pharmacokinetics of Rifampin, Isoniazid, Pyrazinamide, and Ethambutol in Infants Dosed According to Revised WHO-Recommended Treatment Guidelines

2016 ◽  
Vol 60 (4) ◽  
pp. 2171-2179 ◽  
Author(s):  
A. Bekker ◽  
H. S. Schaaf ◽  
H. R. Draper ◽  
L. van der Laan ◽  
S. Murray ◽  
...  
Keyword(s):  
Drug Disposition ◽  
Treatment Guidelines ◽  
Geometric Mean ◽  
Plasma Concentrations ◽  
World Health ◽  
Pharmacokinetic Parameters ◽  
Pharmacokinetic Data ◽  
Maximum Plasma ◽  
Antituberculosis Treatment ◽  
The Mean

ABSTRACTThere are limited pharmacokinetic data for use of the first-line antituberculosis drugs during infancy (<12 months of age), when drug disposition may differ. Intensive pharmacokinetic sampling was performed in infants routinely receiving antituberculosis treatment, including rifampin, isoniazid, pyrazinamide, and ethambutol, using World Health Organization-recommended doses. Regulatory-approved single-drug formulations, including two rifampin suspensions, were used on the sampling day. Assays were conducted using liquid chromatography-mass spectrometry; pharmacokinetic parameters were generated using noncompartmental analysis. Thirty-nine infants were studied; 14 (36%) had culture-confirmed tuberculosis. Fifteen (38%) were premature (<37 weeks gestation); 5 (13%) were HIV infected. The mean corrected age and weight were 6.6 months and 6.45 kg, respectively. The mean maximum plasma concentrations (Cmax) for rifampin, isoniazid, pyrazinamide, and ethambutol were 2.9, 7.9, 41.9, and 1.3 μg/ml, respectively (current recommended adult target concentrations: 8 to 24, 3 to 6, 20 to 50, and 2 to 6 μg/ml, respectively), and the mean areas under the concentration-time curves from 0 to 8 h (AUC0–8) were 12.1, 24.7, 239.4, and 5.1 μg · h/ml, respectively. After adjusting for age and weight, rifampin exposures for the two formulations used differed inCmax(geometric mean ratio [GMR],2.55; 95% confidence interval [CI], 1.47 to 4.41;P= 0.001) and AUC0–8(GMR, 2.52; 95% CI, 1.34 to 4.73;P= 0.005). HIV status was associated with lower pyrazinamideCmax(GMR, 0.85; 95% CI, 0.75 to 0.96;P= 0.013) and AUC0–8(GMR, 0.79; 95% CI, 0.69 to 0.90;P< 0.001) values. No other important differences were observed due to age, weight, prematurity, ethnicity, or gender. In summary, isoniazid and pyrazinamide concentrations in infants compared well with proposed adult target concentrations; ethambutol concentrations were lower but similar to previously reported pediatric studies. The low rifampin exposures require further investigation. (This study has been registered at ClinicalTrials.gov under registration no. NCT01637558.)

scholarly journals Pharmacokinetic study of lenvatinib in Chinese patients with solid tumors

2021 ◽  
Author(s):  
Dan Liu ◽  
Lei Liu ◽  
Lin Shen ◽  
Tomoki Kubota ◽  
Takuya Suzuki ◽  
...  
Keyword(s):  
Steady State ◽  
Geometric Mean ◽  
Plasma Concentrations ◽  
Chinese Patients ◽  
Pharmacokinetic Data ◽  
Maximum Plasma ◽  
Clinical Trial Registration ◽  
Time Curve ◽  
Once Daily ◽  
Appropriate Treatment

Aim: To assess the pharmacokinetics of once-daily oral lenvatinib 24 mg in Chinese patients. Material & methods: Patients had any solid tumor (except hepatocellular carcinoma) that was resistant to standard antitumor therapies or for which no appropriate treatment was available. Results: Twelve patients were enrolled. Maximum plasma concentrations of lenvatinib were observed at 2 and 4 h (median) after single and multiple doses (day 15), respectively. Steady state was achieved within 8 days. The geometric mean maximum observed concentration at steady state was 258 ng/ml (coefficient of variance: 49.2%); and the geometric mean area under the concentration-time curve from zero to 24 h at steady state was 3090 ng•h/ml (coefficient of variance: 44.7%). No accumulation was seen after 15 days. Conclusion: Lenvatinib pharmacokinetic data in Chinese patients are consistent with data in multinational trials, supporting usage of the 24-mg dose. Clinical Trial Registration: NCT03009292 (ClinicalTrials.gov)

scholarly journals Differential Impact of Nevirapine on Artemether-Lumefantrine Pharmacokinetics in Individuals Stratified by CYP2B6 c.516G>T Genotypes

2019 ◽  
Vol 64 (3) ◽  
Author(s):  
Sa’ad T. Abdullahi ◽  
Julius O. Soyinka ◽  
Adeniyi Olagunju ◽  
Rahman A. Bolarinwa ◽  
Olusola J. Olarewaju ◽  
...  
Keyword(s):  
Drug Interaction ◽  
Genetic Polymorphisms ◽  
Drug Disposition ◽  
Geometric Mean ◽  
Plasma Concentrations ◽  
Clinical Malaria ◽  
Pharmacokinetic Parameters ◽  
Drug Drug Interaction ◽  
The Impact ◽  
Hiv Negative

ABSTRACT There is an increased recognition of the need to identify and quantify the impact of genetic polymorphisms on drug-drug interactions. This study investigated the pharmacogenetics of the pharmacokinetic drug-drug interaction between nevirapine and artemether-lumefantrine in HIV-positive and HIV-negative adult Nigerian subjects. Thirty each of HIV-infected patients on nevirapine-based antiretroviral therapy and HIV-negative volunteers without clinical malaria, but with predetermined CYP2B6 c.516GG and TT genotypes, were administered a complete treatment dose of 3 days of artemether-lumefantrine. Rich pharmacokinetic sampling prior to and following the last dose was conducted, and the plasma concentrations of artemether/dihydroartemisinin and lumefantrine/desbutyl-lumefantrine were quantified using tandem mass spectrometry. Pharmacokinetic parameters of artemether-lumefantrine and its metabolites in HIV-infected patients on nevirapine were compared to those in the absence of nevirapine in HIV-negative volunteers. Overall, nevirapine reduced exposure to artemether and desbutyl-lumefantrine by 39 and 34%, respectively. These reductions were significantly greater in GG versus TT subjects for artemether (ratio of geometric mean [90% confidence interval]: 0.42 [0.29 to 0.61] versus 0.81 [0.51 to 1.28]) and for desbutyl-lumefantrine (0.56 [0.43 to 0.74] versus 0.75 [0.56 to 1.00]). On the contrary, it increased exposure to dihydroartemisinin and lumefantrine by 47 and 30%, respectively. These increases were significantly higher in TT versus GG subjects for dihydroartemisinin (1.67 [1.20 to 2.34] versus 1.25 [0.88 to 1.78]) and for lumefantrine (1.51 [1.20 to 1.90] versus 1.08 [0.82 to 1.42]). This study underscores the importance of incorporating pharmacogenetics into all drug-drug interaction studies with potential for genetic polymorphisms to influence drug disposition.

scholarly journals HIV-1 Coinfection Does Not Reduce Exposure to Rifampin, Isoniazid, and Pyrazinamide in South African Tuberculosis Outpatients

2016 ◽  
Vol 60 (10) ◽  
pp. 6050-6059 ◽  
Author(s):  
Neesha Rockwood ◽  
Graeme Meintjes ◽  
Maxwell Chirehwa ◽  
Lubbe Wiesner ◽  
Helen McIlleron ◽  
...  
Keyword(s):  
Body Weight ◽  
Antiretroviral Therapy ◽  
Plasma Concentrations ◽  
Fat Free Mass ◽  
World Health ◽  
Pharmacokinetic Parameters ◽  
Antituberculosis Drug ◽  
Antituberculosis Treatment ◽  
Drug Concentrations ◽  
Hiv 1

ABSTRACTThere are contrasting data in the literature about antituberculosis plasma drug concentrations in HIV-1-coinfected patients. We report the pharmacokinetics of rifampin, isoniazid, and pyrazinamide in a cohort of patients being treated for active tuberculosis, the majority of whom were coinfected with HIV-1 and had commenced antiretroviral therapy within 2 months of starting antituberculosis treatment. We also examined the association between antituberculosis drug concentrations and reported drug side effects at the 2-month clinical review. One hundred patients with pulmonary tuberculosis (65% coinfected with HIV-1) were intensively sampled to determine rifampin, isoniazid, and pyrazinamide plasma concentrations after 7 to 8 weeks of a daily quadruple-therapy regimen dosed according to World Health Organization (WHO) weight bands. Pharmacokinetic parameters were determined for each patient by using nonlinear mixed-effects models. HIV-1-coinfected patients had lower clearance rates for rifampin (21% decrease) and isoniazid (23% decrease) than HIV-1-uninfected patients, with resulting higher areas under the concentration-time curve from 0 to 24 h (AUC0–24) and maximum concentrations of drug in serum (Cmax). Antiretroviral therapy (ART) that included double-standard-dose lopinavir/ritonavir further lowered rifampin clearance, by 46%, and increased the AUC0–24. The current uniform dosing (per kilogram of body weight) across WHO weight bands was associated with a trend of decreased pharmacokinetic exposures for the lowest weight band. Use of fat-free mass as opposed to total body weight for allometric scaling of clearance significantly improved the model. Ambulant HIV-1-coinfected patients, the majority of whom were coprescribed ART, did not have reduced antituberculosis drug concentrations compared to HIV-1-uninfected patients.

scholarly journals Effect of intramuscular methadone on pharmacokinetic data and thermal and mechanical nociceptive thresholds in the cat

2016 ◽  
Vol 18 (11) ◽  
pp. 875-881 ◽  
Author(s):  
Louisa S Slingsby ◽  
John W Sear ◽  
Polly M Taylor ◽  
Joanna C Murrell
Keyword(s):  
Antinociceptive Effect ◽  
Plasma Concentrations ◽  
Pharmacokinetic Parameters ◽  
Blood Collection ◽  
Pharmacokinetic Data ◽  
Maximum Plasma ◽  
Time Data ◽  
Mechanical Threshold ◽  
Liquid Chromatography Tandem Mass ◽  
Methadone Concentration

Objectives The aim of the study was to assess simultaneous pharmacokinetics and thermal and mechanical antinociception after intramuscular methadone (0.6 mg/kg) in 10 cats. Methods Thermal and mechanical threshold (TT and MT, respectively) testing and blood collection were conducted at baseline and up to 24 h after administration. Methadone plasma concentrations were determined by liquid chromatography–tandem mass spectrometry and pharmacokinetic parameters were estimated by a non-compartmental method. TT and MT were analysed using ANOVA ( P <0.05). Time of maximum plasma concentration (Tmax), time of onset of antinociception and time of reaching cut-out threshold (TT 55°C; MT 30 Newtons [N]) were determined. Results TT and MT increased above baseline from 20–240 mins and 5–40 mins, respectively, after intramuscular (IM) administration ( P <0.005). Mean maximum delta T (measured as TT minus baseline threshold) was 7.9°C (95% confidence interval [CI] 4.3–11.6) at 60 mins and mean maximum delta F (measured as MT minus baseline threshold) was 4.2 (95% CI 1.6–6.7) N at 45 mins. IM methadone concentration–time data decreased curvilinearly, and gave a clearance estimate of mean 9.1 ml/kg/min (range 5.2–15.7) with median Tmax at 20 mins (range 5–360 mins). Conclusions and relevance IM data followed classical disposition and elimination in all cats. Plasma concentrations after IM administration were associated with an antinociceptive effect, including negative hysteresis. These data can be used for devising dosing schedules for methadone in clinical feline practice.

scholarly journals Evaluation of the Effect of CYP2D6 Genotypes on Tramadol and O-Desmethyltramadol Pharmacokinetic Profiles in a Korean Population Using Physiologically-Based Pharmacokinetic Modeling

Pharmaceutics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 618 ◽  
Author(s):  
Jeong ◽  
Bae ◽  
Bae ◽  
Lee ◽  
Kim ◽  
...  
Keyword(s):  
Steady State ◽  
Geometric Mean ◽  
Plasma Concentrations ◽  
Korean Population ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Metabolic Clearance ◽  
Concentration Profiles ◽  
Physiologically Based Pharmacokinetic ◽  
Physiologically Based

Tramadol is a μ-opioid receptor agonist and a monoamine reuptake inhibitor. O-desmethyltramadol (M1), the major active metabolite of tramadol, is produced by CYP2D6. A physiologically-based pharmacokinetic model was developed to predict changes in time-concentration profiles for tramadol and M1 according to dosage and CYP2D6 genotypes in the Korean population. Parallel artificial membrane permeation assay was performed to determine tramadol permeability, and the metabolic clearance of M1 was determined using human liver microsomes. Clinical study data were used to develop the model. Other physicochemical and pharmacokinetic parameters were obtained from the literature. Simulations for plasma concentrations of tramadol and M1 (after 100 mg tramadol was administered five times at 12-h intervals) were based on a total of 1000 virtual healthy Koreans using SimCYP® simulator. Geometric mean ratios (90% confidence intervals) (predicted/observed) for maximum plasma concentration at steady-state (Cmax,ss) and area under the curve at steady-state (AUClast,ss) were 0.79 (0.69–0.91) and 1.04 (0.85–1.28) for tramadol, and 0.63 (0.51–0.79) and 0.67 (0.54–0.84) for M1, respectively. The predicted time–concentration profiles of tramadol fitted well to observed profiles and those of M1 showed under-prediction. The developed model could be applied to predict concentration-dependent toxicities according to CYP2D6 genotypes and also, CYP2D6-related drug interactions.

scholarly journals Toxicity and Pharmacokinetic Studies of Lidocaine and Its Active Metabolite, Monoethylglycinexylidide, in Goat Kids

Animals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 142
Author(s):  
Dinakaran Venkatachalam ◽  
Paul Chambers ◽  
Kavitha Kongara ◽  
Preet Singh
Keyword(s):  
Total Dose ◽  
Plasma Concentrations ◽  
Subcutaneous Administration ◽  
Lidocaine Hydrochloride ◽  
Pharmacokinetic Parameters ◽  
Pharmacokinetic Studies ◽  
Liquid Chromatography Mass Spectrometry ◽  
Elimination Half ◽  
The Mean ◽  
Safe Dose

This study determined the convulsant plasma concentrations and pharmacokinetic parameters following cornual nerve block and compared the results to recommend a safe dose of lidocaine hydrochloride for goat kids. The plasma concentrations of lidocaine and monoethylglycinexylidide (MGX) were quantified using liquid chromatography-mass spectrometry. A total dose of 7 mg/kg body weight (BW) was tolerated and should therefore be safe for local and regional anesthesia in goat kids. The mean plasma concentration and mean total dose that produced convulsions in goat kids were 13.59 ± 2.34 µg/mL and 12.31 ± 1.42 mg/kg BW (mean ± S.D.), respectively. The absorption of lidocaine following subcutaneous administration was rapid with Cmax and Tmax of 2.12 ± 0.81 µg/mL and 0.33 ± 0.11 h, respectively. The elimination half-lives (t½λz) of lidocaine hydrochloride and MGX were 1.71 ± 0.51 h and 3.19 ± 1.21 h, respectively. Injection of 1% lidocaine hydrochloride (0.5 mL/site) was safe and effective in blocking the nerves supplying horn buds in goat kids.

scholarly journals Pharmacokinetic Profile of μSMIN Plus™, a new Micronized Diosmin Formulation, after Oral Administration in Rats

2015 ◽  
Vol 10 (9) ◽  
pp. 1934578X1501000 ◽  
Author(s):  
Rosario Russo ◽  
Angelo Mancinelli ◽  
Michele Ciccone ◽  
Fabio Terruzzi ◽  
Claudio Pisano ◽  
...  
Keyword(s):  
Oral Administration ◽  
Plasma Concentrations ◽  
Compartmental Analysis ◽  
Pharmacokinetic Profile ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Sprague Dawley ◽  
Time Curve ◽  
Maximum Plasma Drug Concentration

Diosmin is a naturally occurring flavonoid present in citrus fruits and other plants belonging to the Rutaceae family. It is used for the treatment of chronic venous insufficiency (CVI) for its pheblotonic and vaso-active properties, safety and tolerability as well. The aim of the current in vivo study was to investigate the pharmacokinetic profile of a branded micronized diosmin (μSMIN Plus™) compared with plain micronized diosmin in male Sprague-Dawley rats. After oral administration by gastric gavage, blood samples were collected via jugular vein catheters at regular time intervals from baseline up to 24 hours. Plasma concentrations were assessed by LC/MS. For each animal, the following pharmacokinetic parameters were calculated using a non-compartmental analysis: maximum plasma drug concentration (Cmax), time to reach Cmax (Tmax), area under the plasma concentration-time curve (AUC0-last), elimination half-life (t1/2), and relative oral bioavailability (%F). The results of the current study clearly showed an improvement in the pharmacokinetic parameters in animals treated with μSMIN Plus™ compared with animals treated with micronized diosmin. In particular, μSMIN Plus™ showed a 4-fold increased bioavailability compared with micronized diosmin. In conclusion, the results from the current study provided a preliminary pharmacokinetic profile for μSMIN Plus™, which may represent a new tool for CVI management.

scholarly journals Increased tenofovir monoester concentrations in patients receiving tenofovir disoproxil fumarate with ledipasvir/sofosbuvir

2019 ◽  
Vol 74 (8) ◽  
pp. 2360-2364 ◽  
Author(s):  
Kristina M Brooks ◽  
Jose R Castillo-Mancilla ◽  
Joshua Blum ◽  
Ryan Huntley ◽  
Samantha MaWhinney ◽  
...  
Keyword(s):  
Tenofovir Disoproxil Fumarate ◽  
Clinical Relevance ◽  
Geometric Mean ◽  
Plasma Concentrations ◽  
Dried Blood Spots ◽  
Pharmacokinetic Parameters ◽  
Post Dose ◽  
P Values ◽  
Hydrolysis Of ◽  
Tenofovir Diphosphate

AbstractBackgroundIntracellular tenofovir diphosphate concentrations are markedly increased in HIV/HCV coinfected individuals receiving tenofovir disoproxil fumarate (TDF) with sofosbuvir-containing treatment. Sofosbuvir may inhibit the hydrolysis of TDF to tenofovir, resulting in increased concentrations of the disoproxil or monoester forms, which may augment cell loading. We sought to quantify tenofovir disoproxil and monoester concentrations in individuals receiving TDF with and without ledipasvir/sofosbuvir.MethodsHIV/HCV coinfected participants receiving TDF-based therapy were sampled pre-dose and 1 and 4 h post-dose prior to and 4 weeks after initiating ledipasvir/sofosbuvir. Tenofovir disoproxil was not detectable. Tenofovir monoester in plasma and tenofovir diphosphate in PBMC and dried blood spots (DBS) were quantified using LC-MS/MS. Geometric mean ratios (week 4 versus baseline) and 95% CIs were generated for the pharmacokinetic parameters. P values reflect paired t-tests.ResultsTen participants had complete data. At baseline, geometric mean (95% CI) tenofovir monoester plasma concentrations at 1 and 4 h post-dose were 97.4 ng/mL (33.0–287.5) and 0.74 ng/mL (0.27–2.06), respectively. With ledipasvir/sofosbuvir, tenofovir monoester concentrations at 4 h post-dose were 5.02-fold higher (95% CI 1.40–18.05; P = 0.019), but did not significantly differ at 1 h post-dose (1.72-fold higher, 95% CI 0.25–11.78; P = 0.54), possibly due to absorption variability. Tenofovir diphosphate in PBMC and DBS were increased 2.80-fold (95% CI 1.71–4.57; P = 0.001) and 7.31-fold (95% CI 4.47–11.95; P < 0.0001), respectively, after 4 weeks of ledipasvir/sofosbuvir.ConclusionsTenofovir monoester concentrations were increased in individuals receiving TDF with ledipasvir/sofosbuvir, consistent with inhibition of TDF hydrolysis. Additional studies are needed to determine the clinical relevance of this interaction.

Safety and Pharmacokinetics of Standardized Extract of Centella asiatica (ECa 233) Capsules in Healthy Thai Volunteers: A Phase 1 Clinical Study

Planta Medica ◽  
2019 ◽  
Vol 85 (06) ◽  
pp. 483-490 ◽  
Author(s):  
Phanit Songvut ◽  
Pajaree Chariyavilaskul ◽  
Mayuree Tantisira ◽  
Phisit Khemawoot
Keyword(s):  
Clinical Laboratory ◽  
Phase 1 ◽  
Plasma Concentrations ◽  
Centella Asiatica ◽  
Fold Increase ◽  
Repeated Dose ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Asiatic Acid ◽  
Active Metabolites

AbstractThe aim of this study was to investigate the safety and pharmacokinetic profiles of a newly developed, standardized extract of Centella asiatica (ECa 233) capsule in healthy Thai volunteers. This study was designed as an open-labeled, 2-sequence dosage, single- and repeated-dose study investigated under fasting conditions. Plasma concentrations of the parent compounds and their relative acid metabolites were measured and pharmacokinetic parameters were calculated using noncompartmental analysis. Tolerability was assessed based on physical examinations, monitoring of vital signs, clinical laboratory tests, and any observed adverse events. A key finding of this study was that the pharmacokinetics of ECa 233 in healthy volunteers did not correspond with its pharmacokinetics in animal studies. As indicated in human pharmacokinetic parameters, maximum plasma concentration and area under the curve of the parent compounds (madecassoside and asiaticoside) were very low, while their respective metabolites (madecassic acid and asiatic acid) demonstrated higher values. Based on the pharmacokinetic results observed in the dose comparison, accumulation of active metabolites after repeated dose is highly suggestive. In addition, the asiatic acid profile showed 2-fold increase in Cmax and AUC(0–t) after increasing dose from 250 to 500 mg of ECa 233. Lastly, the safety and tolerability evaluation illustrated that single and multiple doses in both 250 and 500 mg oral administration of ECa 233 were well tolerated, and none of the volunteers discontinued their participation due to adverse effects during the study.

scholarly journals Severe Renal Impairment Has Minimal Impact on Doravirine Pharmacokinetics

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Wendy Ankrom ◽  
Ka Lai Yee ◽  
Rosa I. Sanchez ◽  
Adedayo Adedoyin ◽  
Li Fan ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Renal Impairment ◽  
Severe Renal Impairment ◽  
Geometric Mean ◽  
Plasma Concentrations ◽  
Area Under The Curve ◽  
Transcriptase Inhibitor ◽  
Maximum Plasma ◽  
Minor Effect ◽  
Minimal Impact

ABSTRACT Doravirine is a novel nonnucleoside reverse transcriptase inhibitor in development for use with other antiretroviral therapies to treat human immunodeficiency virus type 1 (HIV-1) infection. Doravirine metabolism predominantly occurs via cytochrome P450 3A with <10% of elimination occurring via the renal pathway. As severe renal impairment can alter the pharmacokinetics (PK) of metabolically eliminated drugs, the effect of severe renal impairment on doravirine PK was assessed. A single dose of doravirine 100 mg was administered to subjects aged 18 to 75 years with an estimated glomerular filtration rate (eGFR) of <30 ml/min/1.73 m2 (severe renal impairment group) and healthy controls with an eGFR of ≥80 ml/min/1.73 m2, matched to the mean of the renal impairment group by age (±10 years) and weight (±10 kg). Doravirine plasma concentrations were determined at regular intervals, and safety was monitored throughout. The geometric mean ratios (90% confidence interval) for severe renal impairment/healthy subjects were 1.43 (1.00, 2.04), 1.38 (0.99, 1.92), and 0.83 (0.61, 1.15) for the plasma doravirine area under the curve from zero to infinity (AUC0–∞), plasma concentration at 24 h postdose (C24), and maximum plasma concentration (Cmax), respectively. Doravirine was generally well tolerated in both groups. Based on the overall efficacy, safety, and PK profile of doravirine, the minor effect of severe renal impairment on doravirine PK observed in this study is not considered clinically meaningful. (This study has been registered at ClinicalTrials.gov under identifier NCT02641067.)

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