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1.
Aims
The regulatory prohibition of ketoconazole as a CYP3A index inhibitor in drug–drug interaction (DDI) studies has compelled consideration of alternative inhibitors.Methods
The biomedical literature was searched to identify DDI studies in which oral midazolam (MDZ) was the victim, and the inhibitory perpetrator was either ketoconazole, itraconazole, clarithromycin, or ritonavir. The ratios (RAUC) of total area under the curve (AUC) for MDZ with inhibitor divided by MDZ AUC in the control condition were aggregated across individual studies for each inhibitor.Results
Mean (± SE) RAUC values were: ketoconazole (15 studies, 131 subjects), 11.5 (±1.2); itraconazole (five studies, 48 subjects), 7.3 (±1.0); clarithromycin (five studies, 73 subjects), 6.5 (±10.9); and ritonavir (13 studies, 159 subjects), 14.5 (±2.0). Differences among inhibitors were significant (F = 5.31, P < 0.005). RAUC values were not significantly related to inhibitor dosage or to duration of inhibitor pre-exposure prior to administration of MDZ.Conclusions
Ritonavir produces CYP3A inhibition equivalent to or greater than ketoconazole, and is the best index CYP3A inhibitor alternative to ketoconazole. Cobicistat closely resembles ritonavir in structure and function, and can also be considered. Itraconazole and clarithromycin are not suitable alternatives since they do not produce inhibition comparable with ketoconazole or ritonavir, and have other significant disadvantages as well. 相似文献2.
Hylke de Jonge Thomas Vanhove Henri?tte de Loor Kristin Verbeke Dirk R J Kuypers 《British journal of clinical pharmacology》2015,80(3):548-559
Aims
The long-term disposition of tacrolimus following kidney transplantation is characterized by a gradual decrease in dose requirements and increase in dose-corrected exposure. This phenomenon has been attributed to a progressive decline in cytochrome P450 3A4 (CYP3A4) activity, although this has never been demonstrated in vivo.Methods
Sixty-five tacrolimus- and 10 cyclosporine-treated renal transplant recipients underwent pharmacokinetic testing at day 7 and months 1, 3, 6 and 12 after transplantation, including 8-h area under the concentration-time curve (AUC) for tacrolimus or cyclosporine and assessment of CYP3A4 activity using oral and intravenous midazolam (MDZ) drug probes.Results
Tacrolimus clearance decreased gradually throughout the entire first year but only in CYP3A5*3/*3 homozygous recipients (25.6 ± 11.1 l h–1 at day 7; 17 ± 9.1 l h–1 at month 12; P < 0.001). In mixed model analysis, decreasing CYP3A4 activity, measured by apparent oral MDZ clearance (924 ± 443 ml min–1 at day 7 vs. 730 ± 344 ml min–1 at month 1; P < 0.001), explained 55.4% of the decline in tacrolimus clearance in the first month. CYP3A4 activity decreased by 18.9 ml min–1 for every milligram of methylprednisolone dose tapering within the first month; beyond this point it remained stable. A gradual rise in haematocrit throughout the entire first year explained 31.7% of the decrease in tacrolimus clearance in the first month and 23.6% of the decrease between months 1 and 12. Cyclosporine clearance did not change over time.Conclusions
The maturation of tacrolimus disposition in the first year after renal transplantation observed in CYP3A5*3/*3 homozygous patients can partly be explained by a (steroid tapering-related) decline in CYP3A4 activity and a progressive increase in haematocrit. 相似文献3.
Priska Kaufmann Séverine Niglis Shirin Bruderer Jér?me Segrestaa P?ivi ??nismaa Atef Halabi Jasper Dingemanse 《British journal of clinical pharmacology》2015,80(4):670-677
Aims
This study investigated the effect of a fixed dose combination of lopinavir/ritonavir on the pharmacokinetics (PK) of selexipag and its active metabolite ACT-333679.Methods
This was an open label, randomized, single centre, two way, crossover study. Twenty healthy male subjects were treated with a single dose of 400 µg selexipag alone and in combination with multiple doses of lopinavir/ritonavir (400/100 mg) twice daily.Results
The results showed that lopinavir/ritonavir approximately doubled the exposure to selexipag. The area under the plasma concentration–time curve from time zero to infinity (AUC(0,∞) and the maximum plasma concentration (Cmax) of selexipag were 2.2- and 2.1-fold higher, respectively, than under selexipag alone, with a 90% confidence interval (CI) of the geometric mean ratio (GMR) of 1.9, 2.7 and 1.7, 2.6, respectively. For ACT-333679, the clinically more relevant component of selexipag, systemic exposure was increased by 8% (GMR of AUC(0,∞) 1.1, 90% CI 0.9, 1.3), when lopinavir/ritonavir was co-administered with selexipag.The most frequently reported adverse event (AE) was headache. A single dose of selexipag, administered either alone or together with multiple doses of lopinavir/ritonavir, was safe and well tolerated.Conclusions
Lopinavir/ritonavir does not affect the PK parameters of selexipag and ACT-333679 to a clinically relevant extent. Therefore, adaptation of the selexipag dose is not required when co-administered with inhibitors of the organic anion-transporting polypeptide (OATP) 1B1/ 1B3, P-glycoprotein (P-gp) and/or CYP3A4. 相似文献4.
Stacy S Shord Lingtak-Neander Chan Joseph R Camp Eva M Vasquez Hyun-Young Jeong Robert E Molokie Charles L Baum Hui Xie 《British journal of clinical pharmacology》2010,69(2):160-166
AIMS
The aim of the study was to determine the effects of oral clotrimazole troches on the pharmacokinetics of oral and intravenous midazolam in the plasma.METHODS
We conducted a randomized, open-label, four-way crossover study in 10 healthy volunteers. Each volunteer received oral midazolam 2 mg or intravenous midazolam 0.025 mg kg−1 with and without oral clotrimazole troches 10 mg taken three times daily for 5 days. Each study period was separated by 14 days. Serial blood samples were collected up to 24 h after oral midazolam and 6 h after intravenous midazolam. Plasma concentrations for midazolam and its metabolite 1-hydroxymidazolam were measured and fitted to a noncompartmental model to estimate the pharmacokinetic parameters.RESULTS
Ten healthy volunteers aged 21–26 years provided written informed consent and were enrolled into the study. Clotrimazole decreased the apparent oral clearance of midazolam from 57 ± 13 l h−1[95% confidence interval 48, 66] to 36 ± 9.8 l h−1 (95% confidence interval 29, 43) (P= 0.003). These changes were accompanied by a decrease in the area under the concentration–time curve (mean difference 22 µg h−1 l−1, P= 0.001) and bioavailability (mean difference 0.21, P= NS). There were no significant differences in the systemic clearance of midazolam with or without clotrimazole troches.CONCLUSIONS
Oral clotrimazole troches decreased the apparent oral clearance of midazolam; no significant differences in the systemic clearance of midazolam were found. 相似文献5.
Nicolas Hohmann Franziska Kocheise Alexandra Carls Jürgen Burhenne Walter E Haefeli Gerd Mikus 《British journal of clinical pharmacology》2015,79(2):278-285
Aim
We aimed to establish a method to assess systemic and pre-systemic cytochrome P450 (CYP) 3A activity using ineffective microgram doses of midazolam.Methods
In an open, one sequence, crossover study, 16 healthy participants received intravenous and oral midazolam at microgram (0.001 mg intravenous and 0.003 mg oral) and regular milligram (1 mg intravenous and 3 mg oral) doses to assess the linearity of plasma and urine pharmacokinetics.Results
Dose-normalized AUC and Cmax were 37.1 ng ml−1 h [95% CI 35.5, 40.6] and 39.1 ng ml−1 [95% CI 30.4, 50.2] for the microdose and 39.0 ng ml−1 h [95% CI 36.1, 42.1] and 37.1 ng ml−1 [95% CI 26.9, 51.3] for the milligram dose. CLmet was 253 ml min−1 [95% CI 201, 318] vs. 278 ml min−1 [95% CI 248, 311] for intravenous doses and 1880 ml min−1 [95% CI 1590, 2230] vs. 2050 ml min−1 [95% CI 1720, 2450] for oral doses. Oral bioavailability of a midazolam microdose was 23.4% [95% CI 20.0, 27.3] vs. 20.9% [95% CI 17.1, 25.5] after the regular dose. Hepatic and gut extraction ratios for microgram doses were 0.44 [95% CI 0.39, 0.49] and 0.53 [95% CI 0.45, 0.63] and compared well with those for milligram doses (0.43 [95% CI 0.37, 0.49] and 0.61 [95% CI 0.53, 0.70]).Conclusion
The pharmacokinetics of an intravenous midazolam microdose is linear to the applied regular doses and can be used to assess safely systemic CYP3A activity and, in combination with oral microdoses, pre-systemic CYP3A activity. 相似文献6.
Zhou D Sunzel M Ribadeneira MD Smith MA Desai D Lin J Grimm SW 《British journal of clinical pharmacology》2012,74(1):98-108
AIM(S)
To investigate the potential of AZD7325 to induce CYP1A2 and CYP3A4 enzyme activities.METHODS
Induction of CYP1A2 and CYP3A4 by AZD7325 was first evaluated using cultured human hepatocytes. The effect of multiple doses of 10 mg AZD7325 on the pharmacokinetics of midazolam and caffeine was then examined in healthy subjects.RESULTS
The highest CYP1A2 and CYP3A4 induction responses were observed in human hepatocytes treated with 1 or 10 µm of AZD7325, in the range of 17.9%–54.9% and 76.9%–85.7% of the positive control responses, respectively. The results triggered the further clinical evaluation of AZD7325 induction potential. AZD7325 reached a plasma Cmax of 0.2 µm after 10 mg daily dosing to steady-state. AZD7325 decreased midazolam geometric mean AUC by 19% (0.81-fold, 90% CI 0.77, 0.87), but had no effect on midazolam Cmax (90% CI 0.82, 0.97). The mean CL/F of midazolam increased from 62 l h−1 (midazolam alone) to 76 l h−1 when co-administered with AZD7325. The AUC and Cmax of caffeine were not changed after co-administration of AZD7325, with geometric mean ratios (90% CI) of 1.17 (1.12, 1.23) and 0.99 (0.95, 1.03), respectively.CONCLUSIONS
While AZD7325 appeared to be a potent CYP3A4 inducer and a moderate CYP1A2 inducer from in vitro studies, the expected efficacious dose of AZD7325 had no effect on CYP1A2 activity and only a weak inducing effect on CYP3A4 activity. This comparison of in vitro and in vivo results demonstrates the critical role that clinical exposure plays in evaluating the CYP induction risk of a drug candidate. 相似文献7.
Laurie P Volak Michael J Hanley Gina Masse Suwagmani Hazarika Jerold S Harmatz Vladimir Badmaev Muhammed Majeed David J Greenblatt Michael H Court 《British journal of clinical pharmacology》2013,75(2):450-462
Aims
Turmeric extract derived curcuminoids (curcumin, demethoxycurcumin and bisdemethoxycurcumin) are currently being evaluated for the treatment of cancer and Alzheimer''s dementia. Previous in vitro studies indicate that curcuminoids and piperine (a black pepper derivative that enhances curcuminoid bioavailability) could inhibit human CYP3A, CYP2C9, UGT and SULT dependent drug metabolism. The aim of this study was to determine whether a commercially available curcuminoid/piperine extract alters the pharmacokinetic disposition of probe drugs for these enzymes in human volunteers.Methods
A randomized placebo-controlled six way crossover study was conducted in eight healthy volunteers. A standardized curcuminoid/piperine preparation (4 g curcuminoids plus 24 mg piperine) or matched placebo was given orally four times over 2 days before oral administration of midazolam (CYP3A probe), flurbiprofen (CYP2C9 probe) or paracetamol (acetaminophen) (dual UGT and SULT probe). Plasma and urine concentrations of drugs, metabolites and herbals were measured by HPLC. Subject sedation and electroencephalograph effects were also measured following midazolam dosing.Results
Compared with placebo, the curcuminoid/piperine treatment produced no meaningful changes in plasma Cmax, AUC, clearance, elimination half-life or metabolite levels of midazolam, flurbiprofen or paracetamol (α = 0.05, paired t-tests). There was also no effect of curcuminoid/piperine treatment on the pharmacodynamics of midazolam. Although curcuminoid and piperine concentrations were readily measured in plasma following glucuronidase/sulfatase treatment, unconjugated concentrations were consistently below the assay thresholds (0.05–0.08 μm and 0.6 μm, respectively).Conclusion
The results indicate that short term use of this piperine-enhanced curcuminoid preparation is unlikely to result in a clinically significant interaction involving CYP3A, CYP2C9 or the paracetamol conjugation enzymes. 相似文献8.
Introduction
This open-label, randomized, two-period drug interaction study assessed lisdexamfetamine dimesylate (LDX) effects on cytochrome P450 (CYP) enzyme (CYP1A2, CYP2D6, CYP2C19, and CYP3A) activity.Methods
Thirty healthy volunteers were administered the Cooperstown cocktail (CYP1A2 [caffeine 200 mg], CYP2D6 [dextromethorphan 30 mg], CYP2C19 [omeprazole 40 mg], and CYP3A [midazolam 0.025 mg/kg] substrates) or Cooperstown cocktail + oral LDX 70 mg. Blood samples for pharmacokinetic analysis were collected pre-dose and serially for 72 h post-dose. Treatment differences in the primary endpoints, maximum plasma concentration (Cmax) and area under the plasma concentration versus time curve from 0 to infinity (AUC0–∞), were assessed using geometric mean ratios with 90 % CIs.Results
Geometric least squares (LS) means (without versus with LDX) for Cmax (ng/mL) were 5370 versus 5246 for caffeine, 2.43 versus 2.87 for dextromethorphan, 35.23 versus 35.11 for midazolam, and 677.9 versus 466.9 for omeprazole; and for AUC0–∞ (ng·h/mL) were 56,207 versus 56,688 for caffeine, 34.85 versus 37.27 for dextromethorphan, 92.07 versus 93.04 for midazolam, and 1428 versus 1499 for omeprazole. Geometric LS mean ratios were within the standard bioequivalence testing range, except for omeprazole and dextromethorphan Cmax. Parent/metabolite Cmax and AUC0–∞ ratios were similar between treatments except for dextromethorphan/dextrorphan AUC0–∞ ratio, which was lower with LDX. No serious or severe treatment-emergent adverse events were reported.Conclusions
LDX did not alter CYP1A2, CYP2D6, or CYP3A activity. A small Cmax reduction for omeprazole and its metabolite was observed, possibly reflecting an effect either on the activity of CYP2C19 or omeprazole absorption.Electronic supplementary material
The online version of this article (doi:10.1007/s40268-015-0090-z) contains supplementary material, which is available to authorized users. 相似文献9.
Albader Albarmawi David Czock Annika Gauss Robert Ehehalt Justo Lorenzo Bermejo Jürgen Burhenne Tom M Ganten Peter Sauer Walter E Haefeli 《British journal of clinical pharmacology》2014,77(1):160-169
Aims
Impaired liver function often necessitates drug dose adjustment to avoid excessive drug accumulation and adverse events, but a marker for the extent of the required adjustment is lacking. The aim of this study was to investigate whether Child–Pugh (CP) and model for end-stage liver disease (MELD) scores correlate with drug clearance.Methods
Midazolam was used as a CYP3A probe and its pharmacokinetics were analyzed in 24 patients with mild to severe liver cirrhosis (n = 4, 10 and 10 with CP class A, B and C, respectively) and six patients without liver disease.Results
Both scores correlated well with unbound midazolam clearance (CLu), unbound midazolam fraction and half-life (all P < 0.01), whereas the unbound steady-state volume of distribution was not significantly changed. In patients with severe liver cirrhosis unbound midazolam clearance was only 14% of controls (CP C: CLu = 843 ± 346 l h−1, MELD ≥ 15: CLu = 805 ± 474 l h−1, controls: CLu = 5815 ± 2649 l h−1, P < 0.01).Conclusion
The correlation with unbound midazolam clearance suggests that either score predicts the metabolic capacity of CYP3A, the most relevant drug metabolizing enzyme subfamily in humans. 相似文献10.
Krishna Kattel Ruby Evande Chalet Tan Goutam Mondal Jean L Grem Ram I Mahato 《British journal of clinical pharmacology》2015,80(2):267-275
Aim
This study evaluated the influence of CYP2C19 polymorphisms on the pharmacokinetics of nelfinavir and its metabolite M8 in patients with pancreatic cancer.Methods
Nelfinavir was administered orally to patients for over 10 days. The plasma concentrations of nelfinavir and M8 were measured by HPLC. The genotypes of CYP2C19*1, CYP2C19*2 and CYP2C19*3 were determined by the polymerase chain reaction-restriction fragment length polymorphism method.Results
Pharmacokinetic profiles of nelfinavir and M8 were characterized by wide interindividual variability. The mean Cmax of nelfinavir in CYP2C19*1/*1 patients was 3.89 ± 0.40 (n = 3) and 5.12 ± 0.41 (n = 30) µg ml–1, while that of CYP2C19*1/*2 patients was 3.60 (n = 1) and 6.14 ± 0.31 (n = 5) µg ml–1 at the doses of 625 and 1250 mg nelfinavir twice daily, respectively. For the M8 metabolite, the mean Cmax of CYP2C19*1/*1 patients was 1.06 ± 0.06 (n = 3) and 1.58 ± 0.27 (n = 30) µg ml–1, while those of CYP2C19*1/*2 patients were 1.01 (n = 1) and 1.23 ± 0.15 (n = 5) µg ml–1 at the doses of 625 and 1250 mg nelfinavir twice daily, respectively. The area under the plasma concentration–time curve (AUC(0,12 h)) values of nelfinavir for CYP2C19*1/*1 patients were 28.90 ± 1.27 and 38.90 ± 4.99 µg ml–1·h and for CYP2C19*1/*2 patients, AUC(0,12 h) was 28.20 (n = 1) and 40.22 ± 3.17 (n = 5) µg ml–1·h at the doses of 625 and 1250 mg nelfinavir twice daily, respectively. The Cmax of nelfinavir was significantly higher (P <0.05) in CYP2C19*1/*2 patients but there was no statistical difference in AUC(0,12 h).Conclusion
CYP2C19*1/*2 genotype modestly affected the pharmacokinetic profiles of nelfinavir and M8 in patients with locally advanced pancreatic cancer. 相似文献11.
John M. Kovarik Hsun-Lun A. Huang Alan Slade Nikos Sfikas & Patricia A. Chandler 《British journal of clinical pharmacology》2009,68(3):381-385
AIMS
Sotrastaurin is an immunosuppressant that reduces T-lymphocyte activation via protein kinase C inhibition. The effect of CYP3A4 inhibition by ketoconazole on the pharmacokinetics of sotrastaurin, a CYP3A4 substrate, was investigated.METHODS
This was a two-period, single-sequence crossover study in 18 healthy subjects. They received a single 50 mg oral dose of sotrastaurin in period 1 followed by a 14-day inter-treatment phase. In period 2 they received ketoconazole 200 mg twice daily for 6 days and a single 50 mg dose of sotrastaurin on the fourth day of ketoconazole administration.RESULTS
Co-administration of single-dose sotrastaurin during steady-state ketoconazole increased sotrastaurin Cmax by 2.5-fold (90% confidence interval 2.2, 2.9) from 285 ± 128 to 678 ± 189 ng ml−1 and increased AUC by 4.6-fold (4.1, 5.2) from 1666 ± 808 to 7378 ± 3011 ng ml−1 h. Sotrastaurin half-life was nearly doubled from 5.9 ± 1.7 to 10.6 ± 2.5 h. The AUC of the active metabolite N-desmethyl-sotrastaurin was increased by 6.8-fold. Sotrastaurin did not alter ketoconazole steady-state predose plasma concentrations.CONCLUSIONS
The strong CYP3A4 inhibitor ketoconazole increased sotrastaurin AUC by 4.6-fold. A compensatory reduction in the dose of sotrastaurin is warranted when strong CYP3A4 inhibitors are co-administered. 相似文献12.
Sandrine Turpault William Brian Robert Van Horn Alix Santoni Franck Poitiers Yves Donazzolo Xavier Boulenc 《British journal of clinical pharmacology》2009,68(6):928-935
AIMS
To assess the pharmacokinetics (PK) of selective substrates of CYP1A2 (caffeine), CYP2C9 (S-warfarin), CYP2C19 (omeprazole), CYP2D6 (metoprolol) and CYP3A (midazolam) when administered orally and concurrently as a cocktail relative to the drugs administered alone.METHODS
This was an open-label, single-dose, randomized, six-treatment six-period six-sequence William''s design study with a wash-out of 7 or 14 days. Thirty healthy male subjects received 100 mg caffeine, 100 mg metoprolol, 0.03 mg kg−1 midazolam, 20 mg omeprazole and 10 mg warfarin individually and in combination (cocktail). Poor metabolizers of CYP2C9, 2C19 and 2D6 were excluded. Plasma samples were obtained up to 48 h for caffeine, metoprolol and omeprazole, 12 h for midazolam, 312 h for warfarin and the cocktail. Three different validated liquid chromatography tandem mass spectrometry methods were used. Noncompartmental PK parameters were calculated. Log-transformed Cmax, AUClast and AUC for each analyte were analysed with a linear mixed effects model with fixed term for treatment, sequence and period, and random term for subject within sequence. Point estimates (90% CI) for treatment ratios (individual/cocktail) were computed for each analyte Cmax, AUClast and AUC.RESULTS
There was no PK interaction between the probe drugs when administered in combination as a cocktail, relative to the probes administered alone, as the 90% CI of the PK parameters was within the prespecified bioequivalence limits of 0.80, 1.25.CONCLUSION
The lack of interaction between probes indicates that this cocktail could be used to evaluate the potential for multiple drug–drug interactions in vivo. 相似文献13.
Imai H Kotegawa T Tsutsumi K Morimoto T Eshima N Nakano S Ohashi K 《British journal of clinical pharmacology》2008,65(5):701-707
AIMS
To examine the recovery time course of CYP3A after enzyme induction by St John''s wort administration.METHODS
The subjects were 12 healthy men, aged 20–33 years. On the first day, they received an oral dose of midazolam 5 mg without St John''s wort (day −14). From the next day, they took St John''s wort for 14 days. On the last day of St John''s wort treatment (day 0) and 3 and 7 days after completion of St John''s wort treatment (days 3 and 7), they received the same dose of midazolam. On each day, blood samples were obtained until 8 h after midazolam administration. Plasma concentrations of midazolam were measured by HPLC. Pharmacokinetic parameters of midazolam were determined using noncompartmental analysis.RESULTS
Apparent oral clearance of midazolam was significantly increased after St John''s wort administration from 65.3 ± 8.4 l h−1 (day −14) to 86.8 ± 17.3 l h−1 (day 0). It returned to the control level 7 days after the completion of St John''s wort (day 7, 59.7 ± 3.8 l h−1). No significant difference in the elimination half-life between the four periods of the study was observed. The changes in apparent oral clearance after St John''s wort discontinuation indicated that CYP3A activity recovers from enzyme induction with an estimated half-life of 46.2 h.CONCLUSIONS
CYP3A activity induced by St John''s wort administration progressively returns to the basal level after approximately 1 week. This finding may provide useful information to avoid clinically significant interactions of St John''s wort with CYP3A substrates.WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT
- St John''s wort causes the induction of CYP3A. Little is known about how long the effect remains after cessation of St John''s wort.
WHAT THIS STUDY ADDS
- The in vivo CYP3A activity returns progressively to the basal level approximately 1 week after cessation of St John''s wort administration
14.
Alexandra Carls Julia Jedamzik Lukas Witt Nicolas Hohmann Juergen Burhenne Gerd Mikus 《British journal of clinical pharmacology》2014,78(6):1433-1440
Aims
Erythromycin is a macrolide antibiotic, which is frequently used as a topical formulation for the treatment of acne. It is also known as an inhibitor of the cytochrome P450 (CYP) isoenzyme 3A4. In this study, the systemic availability of topical erythromycin, hence the influence on the activity of CYP3A, is evaluated in comparison to orally administered erythromycin.Methods
Sixteen healthy volunteers received consecutively topical (two applications of 800 mg) and oral erythromycin (two dose groups, 250 and 1000 mg, with n = 8) to assess erythromycin pharmacokinetics. A microdose of midazolam (3 μg orally) was used to determine the effect on CYP3A activity.Results
After topical administration, erythromycin was detected in the plasma of every participant without causing a statistically significant alteration of CYP3A activity. After oral administration, the dose-normalized erythromycin exposure (AUC∞) was 1335 h ng ml−1 after 250 mg and 3-fold higher after the 1000 mg dose (4051 h ng ml−1; P < 0.01), suggesting nonlinear pharmacokinetics of erythromycin. Both oral doses inhibited CYP3A activity; midazolam clearance was decreased to 61% (250 mg) and 21% (1000 mg). The relationship between erythromycin exposure and CYP3A activity (Hill equation) revealed a 50% reduction of CYP3A activity by an erythromycin AUC∞ of 2106 h ng ml−1.Conclusions
Topical erythromycin did not cause clinically relevant CYP3A alterations, although low systemic availability of erythromycin was observed. This supports the assumption that treatment with topical erythromycin is not critical in terms of CYP3A inhibition. Furthermore, substantial nonlinearity of erythromycin pharmacokinetics after two different oral doses was observed, possibly due to autoinhibition. 相似文献15.
Grün B Merkel U Riedel KD Weiss J Mikus G 《British journal of clinical pharmacology》2012,74(5):854-863
AIMS
To investigate in vivo the effect of the CYP2C19 genotype on the pharmacokinetics of tilidine and the contribution of CYP3A4 and CYP2C19 to the formation of nortilidine using potent CYP3A4 inhibition by ritonavir.METHODS
Fourteen healthy volunteers (seven CYP2C19 poor and seven ultrarapid metabolizers) received ritonavir orally (300 mg twice daily) for 3 days or placebo, together with a single oral dose of tilidine and naloxone (100 mg and 4 mg, respectively). Blood samples and urine were collected for 72 h. Noncompartmental analysis was performed to determine pharmacokinetic parameters of tilidine, nortilidine, bisnortilidine and ritonavir.RESULTS
Tilidine exposure increased sevenfold and terminal elimination half-life fivefold during ritonavir treatment, but no significant differences were observed between the CYP2C19 genotypes. During ritonavir treatment, nortilidine area under the concentration–time curve was on average doubled, with no differences between CYP2C19 poor metabolizers [2242 h ng ml−1 (95% confidence interval 1811–2674) vs. 996 h ng ml−1 (95% confidence interval 872–1119)] and ultrarapid metabolizers [2074 h ng ml−1 (95% confidence interval 1353–2795) vs. 1059 h ng ml−1 (95% confidence interval 789–1330)]. The plasma concentration–time curve of the secondary metabolite, bisnortilidine, showed a threefold increase of time to reach maximal observed plasma concentration; however, area under the concentration–time curve was not altered by ritonavir.CONCLUSIONS
The sequential metabolism of tilidine is inhibited by the potent CYP3A4 inhibitor, ritonavir, independent of the CYP2C19 genotype, with a twofold increase in the exposure of the active nortilidine. 相似文献16.
Michael J Hanley Gina Masse Jerold S Harmatz Paul F Cancalon Gregory G Dolnikowski Michael H Court David J Greenblatt 《British journal of clinical pharmacology》2013,75(4):1041-1052
Aim
The present study evaluated the possibility of drug interactions involving blueberry juice (BBJ) and substrate drugs whose clearance is dependent on cytochromes P4503A (CYP3A) and P4502C9 (CYP2C9).Methods
A 50:50 mixture of lowbush and highbush BBJ was evaluated in vitro as an inhibitor of CYP3A activity (hydroxylation of triazolam and dealkylation of buspirone) and of CYP2C9 activity (flurbiprofen hydroxylation) using human liver microsomes. In clinical studies, clearance of oral buspirone and oral flurbiprofen was studied in healthy volunteers with and without co-treatment with BBJ.Results
BBJ inhibited CYP3A and CYP2C9 activity in vitro, with 50% inhibitory concentrations (IC50) of less than 2%, but without evidence of mechanism-based (irreversible) inhibition. Grapefruit juice (GFJ) also inhibited CYP3A activity, but inhibitory potency was increased by pre-incubation, consistent with mechanism-based inhibition. In clinical studies, GFJ significantly increased area under the plasma concentration−time curve (AUC) for the CYP3A substrate buspirone. The geometric mean ratio (GMR = AUC with GFJ divided by AUC with water) was 2.12. In contrast, the effect of BBJ (GMR = 1.39) was not significant. In the study of flurbiprofen (CYP2C9 substrate), the positive control inhibitor fluconazole significantly increased flurbiprofen AUC (GMR = 1.71), but BBJ had no significant effect (GMR = 1.03).Conclusion
The increased buspirone AUC associated with BBJ is quantitatively small and could have occurred by chance. BBJ has no effect on flurbiprofen AUC. The studies provide no evidence for concern about clinically important pharmacokinetic drug interactions of BBJ with substrate drugs metabolized by CYP3A or CYP2C9. 相似文献17.
Zhong-Ze Fang Yan-Yan Zhang Guang-Bo Ge Hong Huo Si-Cheng Liang Ling Yang 《British journal of clinical pharmacology》2010,69(2):193-199
AIMS
To investigate the inhibition potential and kinetic information of noscapine to seven CYP isoforms and extrapolate in vivo noscapine-warfarin interaction magnitude from in vitro data.METHODS
The activities of seven CYP isoforms (CYP3A4, CYP1A2, CYP2A6, CYP2E1, CYP2D6, CYP2C9, CYP2C8) in human liver microsomes were investigated following co- or preincubation with noscapine. A two-step incubation method was used to examine in vitro time-dependent inhibition (TDI) of noscapine. Reversible and TDI prediction equations were employed to extrapolate in vivo noscapine–warfarin interaction magnitude from in vitro data.RESULTS
Among seven CYP isoforms tested, the activities of CYP3A4 and CYP2C9 were strongly inhibited with an IC50 of 10.8 ± 2.5 µm and 13.3 ± 1.2 µm. Kinetic analysis showed that inhibition of CYP2C9 by noscapine was best fit to a noncompetitive type with Ki value of 8.8 µm, while inhibition of CYP3A4 by noscapine was best fit to a competitive manner with Ki value of 5.2 µm. Noscapine also exhibited TDI to CYP3A4 and CYP2C9. The inactivation parameters (KI and kinact) were calculated to be 9.3 µm and 0.06 min−1 for CYP3A4 and 8.9 µm and 0.014 min−1 for CYP2C9, respectively. The AUC of (S)-warfarin and (R)-warfarin was predicted to increase 1.5% and 1.1% using Cmax or 0.5% and 0.4% using unbound Cmax with reversible inhibition prediction equation, while the AUC of (S)-warfarin and (R)-warfarin was estimated to increase by 110.9% and 48.9% using Cmax or 41.8% and 32.7% using unbound Cmax with TDI prediction equation.CONCLUSIONS
TDI of CYP3A4 and CYP2C9 by noscapine potentially explains clinical noscapine–warfarin interaction. 相似文献18.
Benno Roesch Mary Corcoran Mary Haffey Annette Stevenson Phillip Wang Jaideep Purkayastha Patrick Martin James Ermer 《Drugs in R&D》2013,13(1):53-61
Background
α2-Adrenoceptor agonists are used adjunctively to psychostimulants in treating attention-deficit/hyperactivity disorder (ADHD) when psychostimulants alone do not sufficiently reduce symptoms. However, data on the pharmacokinetic profiles and safety of combination treatments in ADHD are needed.Objective
The primary objective of this study was to evaluate the pharmacokinetic profiles of guanfacine extended release (GXR) and methylphenidate hydrochloride (MPH) extended release, alone and in combination.Study Design
This was an open-label, randomized, three-period crossover, drug–drug interaction study.Setting
The study was conducted at a single clinical research center.Participants
Thirty-eight healthy adults were randomized in this study.Interventions
Subjects were administered single oral doses of GXR (Intuniv®; Shire Development LLC, Wayne, PA, USA) 4 mg, MPH (Concerta®; McNeil Pediatrics, Titusville, NJ, USA) 36 mg, or GXR and MPH combined.Main Outcome Measures
Guanfacine, dexmethylphenidate (d-MPH), and l-methylphenidate (l-MPH) levels were measured with blood samples collected predose and up to 72 h postdose. Safety evaluations included treatment-emergent adverse events (TEAEs), vital signs, and electrocardiograms (ECGs).Results
Thirty-five subjects completed the study. Analyses of the 90 % confidence intervals (CIs) for the geometric mean ratios of the maximum plasma concentration (Cmax) and area under the concentration–time curve extrapolated to infinity (AUC∞) values for guanfacine and d-MPH following administration of GXR or MPH alone or combined met strict bioequivalence criteria (90 % CIs within the interval of 0.80–1.25). Overall, combining GXR and MPH did not alter the pharmacokinetic parameters of either medication. Sixteen subjects (42.1 %) had at least one TEAE. The most commonly reported TEAEs included headache and dizziness following GXR, MPH, and GXR and MPH combined. Two subjects had clinically significant abnormalities in ECG results following coadministration: both events were mild and resolved the same day.Conclusions
In this short-term, open-label study of healthy adults, coadministration of GXR and MPH did not result in significant pharmacokinetic drug–drug interactions. No unique TEAEs were observed with coadministration of GXR and MPH compared with either treatment alone. 相似文献19.
Stefano Zamuner Brendan M Johnson Sabrina Pagliarusco Paolo Fina Michela Peroni Monica Fiore Laurel M Adams Sofia A Fernandes 《British journal of clinical pharmacology》2010,70(4):537-546
AIM
To evaluate the impact of single and repeated doses casopitant on the pharmacokinetics of single dose midazolam and nifedipine (CYP3A substrates) in healthy subjects. The effect on debrisoquine metabolism (CYP2D6 substrate) was also assessed.METHODS
Three open-label studies were conducted in healthy subjects. In the first study subjects received single dose 50 or 100 mg oral casopitant, single dose 5 mg oral midazolam and single dose 10 mg oral debrisoquine. In the other two studies subjects received repeated doses of 10 mg (study 2), 30, or 120 mg oral casopitant and single doses of 5 mg oral midazolam (study 2) and single doses of 10 mg oral nifedipine (study 3). Plasma concentration–time data were analyzed using standard non-compartmental methods. The effect of casopitant on all probes was assessed using geometric means ratios and corresponding 90% confidence intervals (CIs).RESULTS
The AUC(0,∞) of midazolam was increased 1.44-fold (90% CI 1.35, 1.54) and 1.52-fold (90% CI 1.41, 1.65) after co-administration with a single dose of 50 or 100 mg casopitant, respectively. Debrisoquine metabolism was unchanged. After 3 days of casopitant administration, midazolam AUC(0,∞) was increased 1.45- (90% CI 1.32, 1.59), 2.02- (90% CI 1.75, 2.32), and 2.67-fold (90% CI 2.18, 3.27) after co-administration with 10, 30 or 120 mg casopitant, respectively. After 14 days of casopitant administration, midazolam AUC(0,∞) was increased 1.51- (90% CI 1.40, 1.63) to 3.49-fold (90% CI 2.98, 4.08). After 3 days of casopitant administration, nifedipine AUC(0,∞) was increased 1.56- (90% CI 1.37, 1.78) and 1.77-fold (90% CI 1.54, 2.04) after co-administration with 30 or 120 mg casopitant, respectively. Similar increases in nifedipine exposure were observed after 14 days of casopitant administration.CONCLUSIONS
Casopitant is a dose- and duration-dependent weak to moderate inhibitor of CYP3A. 相似文献20.
Gupta P Alvey C Wang R Dowty ME Fahmi OA Walsky RL Riese RJ Krishnaswami S 《British journal of clinical pharmacology》2012,74(1):109-115