摘要:

Clinical Pharmacology and Therapeutics(1993)53,503–514; doi:10.1038/clpt.1993.

ISSN:0009-9236    

DOI:10.1038/clpt.1993.63

年代:1993

数据来源: WILEY

摘要:

Clinical Pharmacology and Therapeutics(1993)53,515–520; doi:10.1038/clpt.1993.

ISSN:0009-9236    

DOI:10.1038/clpt.1993.64

年代:1993

数据来源: WILEY

摘要:

The feasibility of incorporating blood sampling for population pharmacokinetic analysis into postmarketing surveillance was evaluated. Demographic and drug disposition data, consisting of two blood samples collected at a random time during two different dose intervals, was prospectively collected for 94 psychiatric inpatients (mean age, 48 ± 13 years) receiving alprazolam. Mixed‐effect modeling was used to estimate population pharmacokinetic parameters. The mean alprazolam clearance, volume of distribution, and absorption rate constant were 0.05 L/hr/kg, 0.7 L/kg, and 1.1 hr−1respectively. Clearance was increased by 59% in women, decreased by 26% in patients with multiple organ disease, and decreased by 23% in patients older than 60 years of age. These estimates are similar to those determined from rigorous premarketing clinical trials. Interindividual variability in alprazolam clearance was relatively small (40%) after adjustment for significant patient covariates. Population pharmacokinetic analysis represents a reasonable approach to assessment of pharmacokinetic variability in a large, heterogenous patient population.Clinical Pharmacology and Therapeutics(1993)53,521–528; doi:10.1038/clpt.

ISSN:0009-9236    

DOI:10.1038/clpt.1993.65

年代:1993

数据来源: WILEY

摘要:

Caffeine was used to assess acetylation status and indexes of oxidative drug metabolism (demethylation, xanthine oxidation, and 8‐hydroxylation) in a control group and in three groups of patients infected with human immunodeficiency virus (HIV): patients with acquired immunodeficiency syndrome (AIDS) who had acute illnesses, stable patients with AIDS, and asymptomatic patients infected with HIV. The prevalence of apparent slow acetylation was greater in AIDS patients with acute illnesses compared with control subjects (27 of 29 [93%] versus 18 of 29 [62%]). Indexes of demethylation were decreased and 8‐hydroxylation increased in these patients. Xanthine oxidation was the same as that in the control subjects. In the stable AIDS patients, oxidative pathways were altered in a manner similar to that observed in the AIDS patients with acute illnesses, but acetylation was the same as that in the control subjects. In HIV‐infected asymptomatic patients, drug metabolism was the same as that in the control subjects. The increased prevalence of apparent slow acetylation and the altered activity of the oxidative pathways in AIDS patients with acute illnesses may partly explain the increased incidence of adverse drug reactions in these patients.Clinical Pharmacology and Therapeutics(1993)53,529–535; doi:10.1038/clpt

ISSN:0009-9236    

DOI:10.1038/clpt.1993.66

年代:1993

数据来源: WILEY

摘要:

Felbamate is a novel antiepileptic drug that is now available in the United States. During a previous double‐blind, crossover, placebo‐controlled safety and efficacy study, concomitant phenytoin concentrations increased, whereas carbamazepine concentrations decreased. We evaluated the effect of felbamate on the concentrations of carbamazepine and of its major metabolites, carbamazepine‐ 10,11‐epoxide (epoxide) and carbamazepine‐trans‐10,11‐diol (diol) in 26 patients. After the addition of felbamate, mean epoxide concentrations increased from 1.8 µg/ml during placebo or baseline periods to 2.4 µg/ml during felbamate treatment(p<0.05); there was no significant change in diol concentrations. Mean carbamazepine concentrations decreased from 7.5 µg/ml during placebo treatment to 6.1 µg/ml during felbamate treatment(p<0.05). Mechanisms that could account for the increase in steady‐state epoxide concentrations are induction of carbamazepine metabolism to epoxide, inhibition of the conversion of epoxide to diol, or both.Clinical Pharmacology and Therapeutics(1993)53,536–543; do

ISSN:0009-9236    

DOI:10.1038/clpt.1993.67

年代:1993

数据来源: WILEY

摘要:

Objective: To compare the pharmacokinetics of cyclosporine in patients with either cystic fibrosis or Eisenmenger's syndrome.Methods: Patients in the study were heart and lung transplant candidates with either cystic fibrosis(n= 6) or Eisenmenger's syndrome(n= 5), as well as patients who received heart and lung transplantation for either cystic fibrosis(n= 13) or Eisenmenger's syndrome(n= 7). This was an experimental pharmacokinetic study in transplant candidates and an exploratory population pharmacokinetic study in transplant recipients.Results: Patients with cystic fibrosis showed higher blood cyclosporine clearance, higher apparent oral clearance, shorter mean residence time, and more erratic absorption. The coefficient of variation of pharmacokinetic parameters was higher in patients with cystic fibrosis. There were no significant differences in metabolite indexes between the two groups of patients after either oral or intravenous administration. A significant negative correlation was found between cyclosporine clearance and hematocrit (r= 0.81 [95% confidence interval, −0.95 to −0.41]). Dose‐normalized predose blood concentration measurements were lower in patients with cystic fibrosis after transplantation. There was a significant correlation between hematocrit and log dose‐normalized cyclosporine concentration (r= 0.40 [95% confidence interval, 0.30 to 0.49]). The total daily dose per 100 ng/ml trough blood concentration required was estimated to be 2.36 times (95% confidence interval, 1.96 to 2.84) higher in patients with cystic fibrosis.Conclusions: Cyclosporine pharmacokinetics is more variable in patients with cystic fibrosis. The difference in cyclosporine clearance between the two groups is accounted for by differences in binding in blood rather than metabolism. The findings suggest that patients with cystic fibrosis could be conservatively given initial oral doses that are 1.5 times higher than those for patients who receive transplants because of Eisenmenger's syndrome.Clinical Pharmacology and Therapeutics(1993)53,544–554; doi:10.1038/cl

ISSN:0009-9236    

DOI:10.1038/clpt.1993.68

年代:1993

数据来源: WILEY

摘要:

The pharmacokinetics and pharmacodynamics of doxorubicin and its metabolite, doxorubicinol, were studied in 35 adult (mean age, 66½ years) patients with small cell lung cancer after a 1‐hour intravenous infusion at a dose ranging from 45 to 72 mg/m2. All patients also received concomitant therapy with cyclophosphamide and vincristine. Serum concentrations were sampled to 48 hours after dosing. Wide interpatient variability was observed for all pharmacokinetic parameters with coefficients of variation for apparent volume of distribution, clearance, and area under the curve (AUC) of 62%, 65%, and 65%, respectively. Four patients with impaired liver function showed a significant(p<0.05) decrease in clearance (239 versus 666 ml/min/m2) and increases in AUC (4610 versus 1834 ng · hr/ml) and elimination half‐life (49.3 versus 25.6 hours) compared with patients with normal hepatic function. A significant relationship was found between systemic exposure of doxorubicin (defined by AUC) and surviving factor of white blood cells(r= 0.57,p= 0.0025). No relationships were noted between doxorubicinol exposure and surviving factor of white blood cells or platelets. These findings show the important relationship between systemic exposure of doxorubicin and the degree of myelosuppression in patients with small cell lung cancer.Clinical Pharmacology and Therapeutics(1993)53,555–561; doi:10.1038/clpt

ISSN:0009-9236    

DOI:10.1038/clpt.1993.69

年代:1993

数据来源: WILEY

摘要:

Background: The short‐term effects of denopamine, an orally available ß‐stimulant, on exercise capacity were studied in patients with chronic heart failure.Methods and Results: Nineteen patients entered the study. Three patients had ischemic heart disease, 13 had dilated cardiomyopathy, and three had valvular disease; 16 patients were in New York Heart Association class II, and three patients were in New York Heart Association class III. Symptom‐limited exercise testing (ramp protocol) on a bicycle ergometer with gas exchange analysis was conducted 1 hour after oral administration of either 20 mg denopamine or placebo. Drug administration sequence was randomly assigned in a double‐blind crossover method, with 1 week between drugs. Peak V̇o2was 20.4 ±3.2 and 21.2 ± 3.1 ml/min/kg, respectively, for those administered the placebo and the drug, and anaerobic threshold was 13.1 ±2.1 and 14.0 ± 2.0 ml/min/kg. There was a significant increase in peak V̇o2(p<0.05) and anaerobic threshold(p<0.01) with denopamine, whereas no significant change was observed in peak work rate or exercise time. Denopamine increased heart rate in patients with atrial fibrillation but had little effect on heart rate in patients with sinus rhythm.Conclusion: Data obtained from gas exchange analysis are more sensitive and potentially more useful in the detection of short‐term changes in exercise capacity than data obtained from either exercise time or peak work rate, indexes that are commonly used to assess drug therapy. Patients with mild‐to‐moderate heart failure with sinus rhythm, but not those with atrial fibrillation because of its frequent induction of tachycardia, may be good candidates for denopamine therapy.Clinical Pharmacology and Therapeutics(1993)53,562–569; d

ISSN:0009-9236    

DOI:10.1038/clpt.1993.70

年代:1993

数据来源: WILEY

摘要:

Clinical Pharmacology and Therapeutics(1993)53,569; doi:10.1038/clpt.1993.71

ISSN:0009-9236    

DOI:10.1038/clpt.1993.71

年代:1993

数据来源: WILEY

摘要:

The pharmacologie profile of sublingual and subcutaneous buprenorphine, a partial opioid agonist, indicates it may be useful as a maintenance drug in the treatment of opioid dependence. However, illicit intravenous self‐administration suggests that it may have a greater abuse potential by this route of administration. Physiologic and subjective effects of intravenous buprenorphine (0.0, 0.3, 0.6, and 1.2 mg) were determined in a dose‐escalation study in six nondependent volunteers with histories of opioid use. Buprenorphine caused miosis and decreased respiratory rate, increased diastolic blood pressure, and transiently increased heart rate. Buprenorphine increased positive responses on a “feel drug” question and scores on scales of “liking,” “good effects,” euphoria, and apathetic sedation. Physiologic and subjective responses were not consistently dose related, a finding compatable with the pharmacologie profile of a partial agonist. The findings indicate that buprenorphine has substantial potential for abuse when administered intravenously.Clinical Pharmacology and Therapeutics(1993)53,570–576; doi:10

ISSN:0009-9236    

DOI:10.1038/clpt.1993.72

年代:1993

数据来源: WILEY