Journal of Clinical Pharmacology最新文献

To determine acute analgesia by acetylsalicylic acid (ASA) when combined with pseudoephedrine (PSE) in patients with upper respiratory tract infection (URTI), we used the sore throat pain model to measure single-dose effects of ASA 500 mg/PSE 30 mg, ASA 1000 mg/PSE 60 mg, and acetaminophen (APAP) 1000 mg/PSE 60 mg (serving as a positive control). Under double-blind, randomized, placebo-controlled conditions, 640 adult patients with confirmed acute pharyngitis and rhinosinusitis associated with URTI rated throat pain intensity and relief at intervals over 6 hours. Efficacy was demonstrated for both doses of ASA/PSE compared with placebo for all end points, including total pain relief and summed pain intensity differences, beginning at 20 minutes on both scales (all P < .05), and the efficacy of APAP/PSE compared with placebo was confirmed (P < .01). Greater differences in pain relief and intensity were also demonstrated between the higher and lower doses of ASA/PSE (P < .05), in particular, among 329 patients with severe pain, as well as between ASA 1000 mg/PSE 60 mg and APAP 1000 mg/PSE 60 mg (P < .05). No serious adverse events were reported. This study demonstrates that ASA is a well-tolerated and effective analgesic in 500- and 1000-mg doses when combined with pseudoephedrine.

An extended-release trazodone HCl formulation, Trazodone Contramid OAD (TzCOAD), was developed as scored 150-mg and 300-mg caplets for once-daily administration. Dose proportionality of intact and bisected caplets (dose range, 75-375 mg) was evaluated in a single-dose, randomized, 5-way crossover study. Plasma trazodone and m-chlorophenylpiperazine (mCPP) levels were determined using a validated liquid chromatography-tandem mass spectroscopy method. Dose proportionality was assessed based on confidence intervals for logarithmically transformed, dose-normalized maximum plasma concentration (C(max)), area under the plasma concentration versus time data pairs (AUC(0-t)), and area under the curve from time 0 to infinity (AUC(0-∞)) in relation to the acceptance range of 80% to 125% (bioequivalence approach). The power method, combined with confidence interval criteria, was also used to assess proportionality. The conclusion of dose proportionality was generally supported using the bioequivalence approach. Based on the power model, values of the slope and corresponding 90% confidence interval for trazodone C(max), AUC(0-t), and AUC(0-∞) were 0.948 (0.899-0.997), 0.920 (0.875-0.964), and 0.913 (0.867-0.958), respectively. All were within the acceptance interval (0.861-1.139). Results for mCPP also fell within the acceptance interval. TzCOAD exhibits linear pharmacokinetics over doses ranging from 75 to 375 mg and maintains its controlled-release properties when the caplets are bisected along the score line.

Rasagiline is a selective, monoamine oxidase (MAO)-B inhibitor indicated for treatment of Parkinson's disease. This double-blind, placebo-controlled study determined the tyramine sensitivity factor (TSF) and degree of MAO-A inhibition (ie, reduction in plasma dihydroxyphenylglycol) in healthy volunteers who received phenelzine (15 mg, 3 times daily; positive control), selegiline (5 mg, twice daily), or rasagiline (1-6 mg, once daily) for 14 days or rasagiline 2 mg/d for 30 days. The selegiline/rasagiline groups were randomized to placebo or active drug. TSF was highest with phenelzine (17.3) and lowest with placebo (1.5). TSF with selegiline was 2.5. TSFs for rasagiline were as follows: 2.0 for 1 mg/d; 3.3 and 2.4 for 2 mg/d administered for 14 and 30 days, respectively; 4.5 for 4 mg/d; and 5.1 for 6 mg/d. Plasma dihydroxyphenylglycol concentrations suggested that rasagiline 1 mg/d had no effect, whereas rasagiline 2 mg/d had only minimal effect. In contrast, rasagiline 4 and 6 mg/d reduced dihydroxyphenylglycol to a degree approaching that achieved by the positive control phenelzine. Results demonstrate that rasagiline selectively inhibits MAO-B and is not associated with increased tyramine sensitivity at the indicated dose (1 mg/d). These data allowed removal of dietary tyramine restriction from rasagiline US labeling.

Understanding the dose-exposure-response relationship across the pediatric age spectrum from preterm and term newborns to infants, children, adolescents, and adults is a major challenge for clinicians, pharmaceutical companies, and regulatory agencies. Over the past 3 decades, clinical investigations of many drugs commonly used in pediatric therapeutics have provided valuable insights into age-associated differences in drug disposition and action. However, our understanding of the contribution of genetic variation to variability in drug disposition and response in children generally has lagged behind that of adults. This article proposes a systematic approach that can be used to assess the relative contributions of ontogeny and genetic variation for a given compound. Application of the strategy is illustrated using the current regulatory dilemma posed by the safety and effectiveness of over-the-counter cough and cold remedies as an example. The results of the analysis can be used to aid in the design of studies to yield maximally informative data in pediatric populations of different ages and developmental stages and thereby improve the efficiency of study design.

Gender and body weight influence the pharmacokinetics and pharmacodynamics of many drugs. This pooled analysis of 17 clinical studies evaluated the effect of gender, body mass index (BMI), body weight, and lean body weight (LBW) on the pharmacokinetics of the direct renin inhibitor aliskiren in healthy volunteers (n = 392). A separate pooled analysis of 5 clinical studies in patients with hypertension (n = 2327) assessed the influence of gender and BMI on the effects of aliskiren on plasma renin activity and blood pressure. Area under the aliskiren plasma concentration-time curve (AUC(τ)) was 22% lower and the peak aliskiren plasma concentration (C(max)) was 24% lower in men than women (P < .05). BMI was not significantly correlated with AUC(τ) (r = 0.005; P = .917); AUC(τ) was negatively correlated with body weight (r = -0.235; P < .0001) and LBW (r = -0.295; P < .0001). Results were similar for C(max). Adjusting individual aliskiren AUC(τ) and C(max) values for overall mean body weight or LBW abolished gender differences. Based on r(2) values, LBW variation accounted for 8.9% of aliskiren AUC(τ) variation. In patients with hypertension, gender and BMI did not significantly influence the effects of aliskiren on plasma renin activity or blood pressure. It was concluded that lower systemic exposure to aliskiren in men versus women relates to differences in body weight; neither gender nor body weight has clinically relevant effects on the pharmacokinetics or pharmacodynamics of aliskiren.

This study investigated the relationship between pharmacokinetics and pharmacodynamics of mycophenolic acid (MPA) in liver transplant patients receiving mycophenolate mofetil (MMF). Total and free plasma MPA concentrations were determined by high-performance liquid chromatography before MMF dose and at 0.5, 1, 1.5, 2, 4, 6, 8, 10, and 12 hours after dosing in 27 patients. The inhibitory capacity of serum MPA on proliferation of CEM cells was monitored at 0, 1, and 2 hours. The concentration of free MPA at 0, 1, and 2 hours (C(0h), C(1h), C(2h)) and the area under the concentration-time curve at 0 to 12 hours (AUC(0-12h)) of free MPA were significantly related to those of total MPA (P < .05). C(1h) and C(2h) of total and free MPA were conversely related with the rate of proliferation of CEM cells (P < .05). At 1 and 2 hours after an MMF dose, the percentage of CEM cell proliferation was below 40% in the majority of patients compared with the percentage before dosing. Thus, there was a significant relationship between total and free plasma MPA concentrations in liver transplant patients. After MMF dose, the inhibitory capacity of serum MPA on proliferation of CEM cells was enhanced significantly. This effect was related greatly to MPA concentrations.

This study investigates the potential benefits of antibiotics and N-acetylcysteine (NAC), a mucolytic agent, in patients who are candidates for endoscopic retrograde cholangiopancreatography (ERCP) due to partial bile duct obstruction. In total, 102 patients who had choledocholithiasis and choledochal dilatations by abdominal ultrasonography were included in the study. The patients were divided into placebo and NAC therapy groups. Physiological saline (equal volume with NAC solution) and ciprofloxacin (2 × 200 mg/d intravenously) were administered to the placebo group, and NAC (1800 mg/d intravenously) and ciprofloxacin (2 × 200 mg/d intravenously) were administered to the NAC group. In both groups, treatment protocols were administered for 7 days before ERCP. Total and direct bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), C-reactive protein (CRP), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), white blood cell (WBC) count, and neutrophil percent (NE%) levels were measured before the 7-day treatment protocol. The same measurements were also evaluated before ERCP. In the NAC group, the levels of ALP, GGT, WBC, CRP, and NE% decreased significantly (P < .001), whereas a significant decrease did not occur in the placebo group. The combined usage of NAC and ciprofloxacin can be an alternative therapeutic option until ERCP is performed in partial cholestatic patients.

This article describes how a model-based analysis was used to aid development of a novel formulation technology. Paracetamol (acetaminophen) was used as the motivating example with 4 different formulations (2 developmental and 2 commercial) compared using stochastic (Monte Carlo) pharmacokinetic (PK)-pharmacodynamic (PD) simulations to explore potential differences in pharmacodynamic outcomes. PK models were developed from data collected during an intensively sampled, 4-arm crossover trial in 25 fasted healthy subjects, administered 1 g of paracetamol in 4 different formulations. The PK models were linked to a previously published PD model that quantified pain relief over time following tonsillectomy. The number needed to treat (NNT) was the primary numeric used to compare effectiveness. The developmental formulations were likely to produce faster and greater analgesia with an NNT (compared with placebo) to reduce pain by 50% over a 45-minute interval post dose of 2.75 and 2.88 compared with 4.31 and 3.2 for the commercial products. Over the course of 1 hour, all formulations were comparable. The stochastic simulations provided support that the novel formulation technology was likely to provide a clinically meaningful advantage and should be developed further.

RO5068760, a substituted hydantoin, represents a new class of potent, highly selective, non-adenosine triphosphate (ATP)-competitive MEK1/2 inhibitors. The study aimed to determine the safety/tolerability, pharmacokinetics, and pharmacodynamics of single ascending doses of RO5068760 in human healthy volunteers. All participants received a single dose followed by 48 hours of pharmacokinetics, pharmacodynamics, and safety/tolerability assessments. The pharmacodynamics were measured by changes in ERK phosphorylation (pERK) in peripheral blood mononuclear cells, ex vivo stimulated by phorbol 12-myristate 13-acetate (PMA). Forty-eight participants received 6 doses (50, 100, 200, 400, 600, 800 mg). RO5068760 was well tolerated up to 800 mg. There were no clinically significant safety findings, including laboratory, electrocardiogram, ophthalmological assessment, and fecal occult blood tests. Of the total 13 adverse events (n = 12), 11 were mild, 2 were moderate, and none were severe, and only 5 were considered by the investigator as possibly related to treatment. RO5068760 was absorbed with a t(max), of 2 hours. Disposition appeared to be biphasic with a terminal elimination t(1/2) of 5 to 9 hours. The variability was moderate to high, ranging from 38% to 62% for C(max) and 41% to 69% AUC. Within the dose range tested, pERK inhibition was relatively modest with a mean maximal pERK suppression of 55%.

Telcagepant is a novel, orally active, and selective calcitonin gene-related peptide receptor antagonist being developed for acute treatment of migraine with and without aura. Three separate clinical studies were conducted to evaluate the pharmacokinetics and tolerability of telcagepant following single oral doses in healthy young and elderly men and women and multiple oral doses in men. Telcagepant was rapidly absorbed with a time to maximum concentration of approximately 1.5 hours. The terminal half-life was approximately 6 hours. A greater than dose-proportional increase was observed in the area under the plasma concentration versus time curve from zero to infinity. Following twice-daily dosing, with each dose separated by 2 hours, steady state was achieved in approximately 3 to 4 days with an accumulation ratio of approximately 2. There were no clinically meaningful pharmacokinetic differences when compared across age and gender. Telcagepant was generally well tolerated up to single doses of 1200 mg and multiple doses of 400 mg twice daily.