Dose optimization of piperacillin/tazobactam in critically ill children.

Objectives: To characterize the population pharmacokinetics of piperacillin and tazobactam in critically ill infants and children, in order to develop an evidence-based dosing regimen.

Patients And Methods: This pharmacokinetic study enrolled patients admitted to the paediatric ICU for whom intravenous piperacillin/tazobactam (8:1 ratio) was indicated (75 mg/kg every 6 h based on piperacillin). Piperacillin/tazobactam concentrations were measured by an LC-MS/MS method.

Pharmacotherapy in pediatric epilepsy: from trial and error to rational drug and dose selection - a long way to go.

Introduction: Whereas ongoing efforts in epilepsy research focus on the underlying disease processes, the lack of a physiologically based rationale for drug and dose selection contributes to inadequate treatment response in children. In fact, limited information on the interindividual variation in pharmacokinetics and pharmacodynamics of anti-epileptic drugs (AEDs) in children drive prescription practice, which relies primarily on dose regimens according to a mg/kg basis. Such practice has evolved despite advancements in pediatric pharmacology showing that growth and maturation processes do not correlate linearly with changes in body size.

Nitrated apolipoprotein A-I, a potential new cardiovascular marker, is markedly increased in low high-density lipoprotein cholesterol subjects.

Background: Oxidative stress plays an important role in the pathogenesis of coronary artery disease. Recent work showed that high-density lipoproteins isolated from atherosclerotic lesions and blood of patients with established coronary artery disease contain elevated levels of nitrated apolipoprotein A-I. Methods to quantify nitrated apolipoprotein A-I in the plasma may facilitate in the determination of a correlation between plasma levels of nitrated apolipoprotein A-I and risk of atherosclerosis.

Lamotrigine does not prolong QTc in a thorough QT/QTc study in healthy subjects.

Aim: To characterize the effects of lamotrigine on QT interval in healthy subjects.

Methods: Healthy subjects received a single oral dose of moxifloxacin (400 mg) or placebo in crossover design, followed by a dose-escalating regimen of lamotrigine (n = 76) over a 77-day period, or matched placebo (n = 76). Blood samples were taken for determination of moxifloxacin and lamotrigine concentrations and digital 12-lead ECGs were recorded.

Family history of depression is associated with younger age of onset in patients with recurrent depression.

Background: Genetic epidemiology data suggest that younger age of onset is associated with family history (FH) of depression. The present study tested whether the presence of FH for depression or anxiety in first-degree relatives determines younger age of onset for depression.

Method: A sample of 1022 cases with recurrent major depressive disorder (MDD) was recruited at the Max Planck Institute and at two affiliated hospitals.

Validation of a quantitative magnetic resonance method for measuring human body composition.

Objective: To evaluate a novel quantitative magnetic resonance (QMR) methodology (EchoMRI-AH, Echo Medical Systems) for measurement of whole-body fat and lean mass in humans.

Methods And Procedures: We have studied (i) the in vitro accuracy and precision by measuring 18 kg Canola oil with and without 9 kg water (ii) the accuracy and precision of measures of simulated fat mass changes in human subjects (n = 10) and (iii) QMR fat and lean mass measurements compared to those obtained using the established 4-compartment (4-C) model method (n = 30).

Results: (i) QMR represented 18 kg of oil at 40 degrees C as 17.

Pharmacokinetic interaction between fosamprenavir-ritonavir and rifabutin in healthy subjects.

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.

The effects of the TRPV1 antagonist SB-705498 on TRPV1 receptor-mediated activity and inflammatory hyperalgesia in humans.

TRPV1 is a cation channel activated by a range of noxious stimuli and highly expressed in nociceptive fibres. TRPV1 receptors are involved in pain and sensitisation associated with tissue injury and inflammation; hence, TRPV1 antagonists are potentially useful for the treatment of such pain states. SB-705498 is a potent, selective and orally bioavailable TRPV1 antagonist with demonstrated efficacy in a number of preclinical pain models.

Fosamprenavir plus ritonavir increases plasma ketoconazole and ritonavir exposure, while amprenavir exposure remains unchanged.

Plasma ketoconazole (KETO), amprenavir (APV), and ritonavir (RTV) pharmacokinetics were evaluated in 15 healthy subjects after being treated with KETO at 200 mg once daily (QD), fosamprenavir (FPV)/RTV at 700/100 mg twice daily (BID), and then KETO at 200 mg QD plus FPV/RTV at 700/100 mg BID in this open-label study. The KETO area under the concentration-time curve at steady state was increased 2.69-fold with FPV/RTV.

Effect of bupropion extended release on negative emotion processing in major depressive disorder: a pilot functional magnetic resonance imaging study.

Background: Prior imaging studies suggest that patients with major depressive disorder have abnormalities in frontal and limbic neural circuitry including the amygdala, which is relatively more activated at rest and in response to negative emotional stimuli (sadness, fear, etc.) in depressed patients than in controls. Concurrently, patients with depression may have decreased activation of attentional executive regions in response to attentional stimuli.

Safety and pharmacokinetics of brecanavir, a novel human immunodeficiency virus type 1 protease inhibitor, following repeat administration with and without ritonavir in healthy adult subjects.

Brecanavir (BCV) is a novel, potent protease inhibitor in development for the treatment of human immunodeficiency virus (HIV-1) infection with low nM in vitro 50% inhibitory concentrations (IC50s) against many multiprotease inhibitor resistant viruses. This study was a double-blind, randomized, placebo-controlled repeat-dose escalation to evaluate the safety, tolerability, and pharmacokinetics of BCV, with or without ritonavir (RTV), in 68 healthy subjects. Seven sequential cohorts (n=10) received BCV (50 to 600 mg) in combination with 100 mg RTV (every 12 h [q12h] or q24h) or alone at 800 mg q12h for 15 days.

Effects of oral pregabalin and aprepitant on pain and central sensitization in the electrical hyperalgesia model in human volunteers.

Background: Central sensitization is an important mechanism of neuropathic pain; its human models could be useful for early detection of efficacy of novel treatments. The electrical hyperalgesia model invokes central sensitization by repetitive stimulation of the skin. To assess its predictive value, we have investigated pregabalin, a standard neuropathic pain treatment, and aprepitant, an NK(1) antagonist, as an example of a drug class active in animal models but not in neuropathic pain patients.

Pharmacokinetic and pharmacodynamic comparison of controlled-release carvedilol and immediate-release carvedilol at steady state in patients with hypertension.

Carvedilol is indicated for the treatment of essential hypertension and mild-to-severe chronic heart failure, as well as the reduction of cardiovascular mortality in clinically stable post-myocardial infarction patients with left ventricular dysfunction. Carvedilol is a racemic mixture of R(+) and S(-) enantiomers that combines beta(1)-, beta(2)-, and alpha(1)-adrenoceptor blockade. For all indications, the immediate-release (IR) formulation of carvedilol is taken twice daily.

Ranitidine (Zantac) syrup versus Ranitidine effervescent tablets (Zantac) EFFERdose) in children: a single-center taste preference study.

Background: The histamine H(2) receptor antagonist ranitidine is US FDA-approved for the treatment of gastroesophageal reflux disease and healing of erosive esophagitis in children >or=1 month of age. A low-dose strength of ranitidine is now available in a citrus-flavored 25 mg effervescent tablet (dissolved in 5 mL of water); this formulation was developed to facilitate use in infants and smaller children. Ranitidine syrup is available in a peppermint-flavored 15 mg/mL formulation.

Coadministration of esomeprazole with fosamprenavir has no impact on steady-state plasma amprenavir pharmacokinetics.

Objectives: To evaluate the drug interaction between fosamprenavir (FPV) and esomeprazole (ESO) after repeated doses in healthy adults.

Methods: Subjects received ESO 20 mg once daily (qd) for 7 days followed by either ESO 20 mg qd + FPV 1400 mg twice daily (bid) or ESO 20 mg qd + FPV 700 mg bid + ritonavir (RTV) 100 mg bid for 14 days in arms 1 and 2, respectively. After a 21- to 28-day washout, subjects received either FPV 1400 mg bid for 14 days (arm 1) or FPV 700 mg bid + RTV 100 mg bid for 14 days (arm 2).

Ritonavir increases plasma amprenavir (APV) exposure to a similar extent when coadministered with either fosamprenavir or APV.

To compare the effect of ritonavir on plasma amprenavir pharmacokinetics, healthy adults received either fosamprenavir (700 mg twice a day [BID]) or amprenavir (600 mg BID) alone and in combination with ritonavir (100 mg BID). Ritonavir increased plasma amprenavir pharmacokinetic parameters to a similar extent when coadministered with either fosamprenavir or amprenavir.

A randomized, double-blind, placebo-controlled, parallel-group study to assess the efficacy and safety of dual ACE/NEP inhibitor GW660511X in mild-to-moderate hypertensive patients.

This multicentre, double-blind, placebo-controlled, parallel-group study determined the efficacy and safety of GW660511 200 mg, a dual inhibitor of angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP), in mild-to-moderate hypertensive patients (diastolic blood pressure (DBP), > or =90 and < or =109 mm Hg; systolic blood pressure (SBP), > or =150 and < or =180 mm Hg). After a single-blind 2- to 4-week placebo run-in period, 123 patients (aged 18-65 years) were randomized to either placebo (n=62) or to active treatment (n=61) consisting of two consecutive 3-day dose titration periods of GW660511X 50 mg once daily and 100 mg once daily followed by GW660511X 200 mg once daily for 14 days. GW660511X 200 mg significantly lowered (baseline and placebo-corrected) both trough mean cuff SBP (-8.

Comparison of the systemic pharmacodynamic effects and pharmacokinetics of salmeterol delivered by CFC propellant and non-CFC propellant metered dose inhalers in healthy subjects.

This was a randomised, double-blind, placebo-controlled, cross-over study comparing the systemic pharmacodynamic effects (heart rate and serum potassium) and pharmacokinetics of salmeterol delivered by the non-CFC hydrofluoralkane (HFA) propellant 134a and the CFC propellant (propellant 11/12) metered dose inhalers (MDI) in healthy subjects. At the therapeutic dose (50 microg), salmeterol-mediated systemic pharmacodynamics were equivalent for the HFA and CFC MDIs. Higher doses of salmeterol (150 and 300 microg) produced dose-related beta-agonist pharmacodynamic effects irrespective of the propellant.

Application of transcriptome analysis to clinical pharmacology studies.

Clinical pharmacology is the investigation of drug effects in humans. This review discusses the basic tenets of clinical pharmacology research, including pharmacokinetic and pharmacodynamic analysis, therapeutic window, and clinical trial design, and the issues that may arise in the application of transcriptome analysis to clinical pharmacology studies. Examples of how transcriptome analysis can be applied to clinical pharmacology research are described, including a model system of endotoxin challenge (in vitro and in vivo), and an example of a cross-over drug study in normal volunteers.

Pharmacodynamics and pharmacokinetics of oral contraceptives co-administered with alosetron (Lotronex).

The 5-HT3 receptor antagonist alosetron (Lotronex) is indicated for use in women with severe, chronic, diarrhea-predominant irritable bowel syndrome (IBS) who have failed conventional therapy. Oral contraceptives (OCs) and alosetron are potential co-medications in women of childbearing age. This study assessed the effect of alosetron co-administration on pharmacodynamic markers of contraceptive efficacy, on the pharmacokinetics of estrogen and progesterone OC components, and on the activity of biochemical markers for the risk of thrombosis.

Pharmacokinetics and pharmacodynamics of argatroban in combination with a platelet glycoprotein IIB/IIIA receptor antagonist in patients undergoing percutaneous coronary intervention.

The pharmacokinetic-pharmacodynamic (PK-PD) relationship of argatroban, administered in combination with a platelet glycoprotein IIb/IIIa receptor antagonist, was characterized in patients undergoing percutaneous coronary intervention (PCI). Plasma argatroban and activated clotting times (ACTs) were assessed periprocedurally in 152 patients administered argatroban (250- or 300-microg/kg bolus, then 15-microg/kg/min infusion) in combination with abciximab or eptifibatide during PCI. The PK and PK-PD models were developed utilizing a sequential population approach in NONMEM.

Alosetron repeat dose pharmacokinetics, effects on enzyme activities, and influence of demographic factors.

Aim: To assess the pharmacokinetics of alosetron, its effect on in vivo enzyme activities, and influence of demographic factors during repeated dosing.

Methods: Thirty healthy men and women received 1 mg oral alosetron twice-daily for 29.5 days and a single oral dose of a metabolic probe cocktail before and on the last day of alosetron dosing.

Bioavailability of fluticasone propionate and mometasone furoate aqueous nasal sprays.

Objectives: To compare the systemic exposure for intranasal mometasone furoate (MF) and fluticasone propionate (FP) aqueous nasal sprays (ANS) in terms of serum and urinary cortisol parameters and plasma pharmacokinetics.

Methods: Twelve healthy subjects completed this three-way, cross-over study. They received FPANS (50 microg/spray), MFANS (50 microg/spray) or placebo ANS, eight sprays per nostril every 8 h for 4 days.

Equivalent steady-state pharmacokinetics of lamivudine in plasma and lamivudine triphosphate within cells following administration of lamivudine at 300 milligrams once daily and 150 milligrams twice daily.

Once-daily administration of 300 mg of lamivudine in combination with other antiretroviral agents has been proposed as a possible way to optimize anti-human immunodeficiency virus (HIV) treatment and to facilitate adherence. A single-center, randomized, two-way, crossover study was conducted in 60 healthy subjects to compare the steady-state pharmacokinetics of lamivudine in plasma and its putative active anabolite, lamivudine 5'-triphosphate (lamivudine-TP), in peripheral blood mononuclear cells (PBMCs) following 7 days of treatment with lamivudine at 300 mg once daily and 7 days of the standard regimen of 150 mg twice daily. Serial blood samples were collected over 24 h for determination of plasma lamivudine concentrations by liquid chromatography-mass spectrometry and intracellular lamivudine-TP concentrations in peripheral blood mononuclear cells by high-performance liquid chromatography/radioimmunoassay methods.

A Gilbert's syndrome UGT1A1 variant confers susceptibility to tranilast-induced hyperbilirubinemia.

Tranilast (N-(3'4'-demethoxycinnamoyl)-anthranilic acid (N-5)) is an investigational drug for the prevention of restenosis following percutaneous transluminal coronary revascularization. An increase in bilirubin levels was observed in 12% of patients upon administration of tranilast in a phase III clinical trial. To identify the potential genetic factors that may account for the drug-induced hyperbilirubinemia, we examined polymorphisms in the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene in over a thousand patients.