Smoking behaviour modulates pharmacokinetics of orally administered clopidogrel.
ABSTRACT Clopidogrel is an important antiplatelet drug that is effective in preventing thrombotic events, especially for patients undergoing percutaneous coronary intervention. The therapeutic usefulness of clopidogrel has been limited by documented inter-individual heterogeneity in platelet inhibition, which may be attributable to known clopidogrel pharmacokinetic variability. The objective of this study was to assess the influence of smoking cigarettes and abnormal body weight on the pharmacokinetics of clopidogrel.
Seventy-six healthy adult male volunteers were selected randomly. Each subject received a single 75 mg oral dose of clopidogrel after overnight fast. Clopidogrel carboxylate plasma levels were measured and non-compartmental analysis was used to determine peak plasma concentration (C(max)), time to peak plasma concentration (T(max)), elimination half-life (t(1/2e)), and area under the curve (AUC(0-->infinity)).
One-third of volunteers were smokers (n = 27) and one-half had abnormal body weight (n = 39). Smokers had lower AUC(0-->infinity) (smokers: 6.24 +/- 2.32 microg/h/mL vs. non-smokers: 8.93 +/- 3.80 microg/h/mL, P < 0.001) and shorter half-life (smokers: 5.46 +/- 2.99 vs. non-smokers: 8.43 +/- 4.26, P = 0.001). Smoking behaviour had no influence on C(max) (P = 0.3) and T(max) (P = 0.7). There was no statistically significant difference in C(max), AUC(0-->infinity), T(max) and t(1/2e) between volunteers with abnormal body weight and normal body weight. However the difference in body weight of the two groups was relatively narrow (mean +/- SE; 26.93 +/- 0.16 vs. 23.11 +/- 0.27). In general, the pharmacokinetic parameters were characterized by considerable inter-individual differences (C(max) = 3.09 +/- 0.99 microg/mL, CV = 32%), (T(max) =0.76 +/- 0.24 h, CV = 31.6%), (AUC(0-->infinity) = 7.98 +/- 3.58 microg/h/mL, CV = 44.8%), and (t(1/2e) = 7.38 +/- 4.10 h, CV = 55.6%).
Smoking is a significant factor affecting the pharmacokinetics of clopidogrel, following administration of a single 75 mg dose in healthy young volunteers. The study supports smoking-cessation recommendations. Further studies are required to evaluate the influence of smoking and body weight on the pharmacokinetics of the active metabolite of clopidogrel and on the clinical effects of any differences observed.
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ABSTRACT: Data from 30 years of biennial examinations and mortality information on the men who participated in the Framingham Study were analyzed to explore the relation between relative weight and longevity. Metropolitan Relative Weight, as measured at the baseline examination, was strongly related to mortality in the subsequent 30 years, with men weighing between 100% and 109% having minimum mortality. In addition, interim relative weights were related to death in the next 2-year period by cross-sectional pooling analysis. Multivariate analysis showed a strong positive relationship between baseline relative weight and death occurring in any interval, despite an inverse relation between interim weight and death. Overweight (weight greater than 110%) nonsmoking men in the Framingham Study had 30-year mortality rates up to 3.9 higher than men of desirable weight (weight, 100% to 109%). No evidence was seen that weight gains during middle age increased longevity or that desirable weights increased with age.Annals of internal medicine 01/1986; 103(6 ( Pt 2)):1006-9. · 13.98 Impact Factor
Article: Pharmacokinetics of clopidogrel.[show abstract] [hide abstract]
ABSTRACT: Clopidogrel is extensively metabolized, as evidenced by the absence of detectable amounts of unchanged clopidogrel in plasma samples in most clinical trials. The major circulating compound is the inactive carboxylic acid derivative SR26334, and information on the absorption and elimination of clopidogrel after oral administration is derived from the pharmacokinetics of this metabolite. Single-dose pharmacokinetics of SR26334 were investigated in a randomized, dose-proportionality study comparing single 50, 75, 100, and 150 mg oral doses of clopidogrel administered to 12 subjects. Multiple-dose pharmacokinetics of SR26334 were primarily derived from a study carried out in 18 subjects treated with clopidogrel 75 mg once daily for 14 days. Further data on multiple-dose pharmacokinetics were provided by the results of a long-term study carried out in a group of 35 subjects who received clopidogrel 75 mg once daily for 12 weeks. All subjects were healthy male volunteers and, in all cases, clopidogrel was taken in the morning after an overnight fast. The mean Cmax values (+/-SD) for SR26334 following single doses of 50, 75, 100, and 150 mg were 1.6+/-0.30 mg/L, 2.9+/-0.68 mg/L, 3.1+/-0.94 mg/L, and 4.9+/-1.22 mg/L, respectively. The ANOVA performed on dose-normalized Cmax showed no statistically significant dose effect, demonstrating a dose-proportional increase of Cmax in this range of clopidogrel doses. The urinary excretion of SR26334 was low-2.2 to 2.4% of the dose administered-and Cl(r-2-24) remained virtually constant at all four doses. Median T(max)(0.8-1.0 hour) and mean plasma t1/2 (7.2-7.6 hours) values were not significantly different between doses. Following repeated dosing with clopidogrel 75 mg, mean (+/-SD) C(trough) values (values before dosing) for SR26334 at steady state ranged from 0.8+/-0.04 mg/L to 0.11+/-0.07 mg/L. These values are similar to those observed during the 12-week administration of clopidogrel indicating that steady-state values are reproducible and that the esterasic biotransformation of clopidogrel into its carboxylic acid metabolite remains constant over a number of months of treatment.Seminars in Thrombosis and Hemostasis 02/1999; 25 Suppl 2:25-8. · 4.22 Impact Factor
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ABSTRACT: Two open, randomized, crossover bioavailability studies were carried out to assess the influence of concurrent antacid medication and food on the bioavailability of clopidogrel. A fed/fasting study was conducted in 12 elderly male subjects. Each subject took a single 75 mg dose of clopidogrel on two occasions-in the morning after an overnight fast, either during a standardized breakfast, or with breakfast delayed by 4 hours after dosing. A washout period of 7 days was observed between the two dosings. Twelve healthy male subjects participated in the antacid study. They fasted overnight and for 4 hours after dosing and took a single 75 mg dose of clopidogrel at 8:00 a.m. on two occasions separated by a washout period of 14 days. For one dose, Maalox 2 x 400 mg tablets were taken 1 hour before the clopidogrel dose. Pharmacokinetic parameters of SR26334, the main circulating metabolite of clopidogrel, were derived from plasma concentrations of the latter compound determined before and at regular intervals over 36 hours after dosing. For the fed/fasting study, mean Cmax values (+/-SD) were 2.7+/-0.62 mg/L and 2.1+/-0.96 mg/L for the fasting state and the fed state, respectively and the 90% CI of Cmax ratio was [0.57 - 0.97]. Mean AUC(0-obs) values (AUC to the last observed value) were 7.1+/-1.6 mg.h/L and 7.4+/-1.64 mg.h/L, respectively, and the 90% Cl of AUC ratios were [0.90 - 1.02] and [0.89 - 0.97], respectively. For the antacid study, mean Cmax values were 2.6+/-0.84 mg/L and 2.5+/-0.87 mg/L for the no-antacid regimen and the antacid regimen, respectively, and the 90% CI of Cmax ratio was [0.74 - 1.16]. Mean AUC(0-obs) values were 6.3+/-1.34 mg.h/L and 5.8+/-1.33 mg.h/L, respectively, and the 90% CI of AUC ratios was [0.89+/-0.97]. Thus, exposure to SR26334, and therefore net absorption of clopidogrel, was not significantly modified by food or by prior antacid ingestion.Seminars in Thrombosis and Hemostasis 02/1999; 25 Suppl 2:47-50. · 4.22 Impact Factor