Twenty-two healthy women participated in a study to determine whether roxithromycin (a new macrolide antibiotic agent) obtunds the activity of a triphasic oral contraceptive. The duration of the study was four menstrual cycles. Medication was given as follows: (1) cycle 1, no medication to demonstrate ovulation; (2) cycle 2, triphasic oral contraceptive daily to suppress ovulation; (3) cycle 3, triphasic oral contraceptive daily plus roxithromycin, 150 mg b.i.d.; and (4) cycle 4, triphasic oral contraceptive daily plus rifampin, 300 mg daily. Sonography of the ovaries was performed on day 13, and serum progesterone was measured on day 21 of each cycle. Elevated progesterone indicated ovulation. The presence of a maturing follicle supported this finding. All volunteers ovulated in the first cycle and no volunteers ovulated in the second and third cycles. However, 11 women ovulated when rifampin and the triphasic oral contraceptive were given concomitantly. The findings suggest there is no reason to believe that roxithromycin interferes with the efficacy of oral contraceptives.
Twenty-six healthy males took part in this double-blind, randomised, placebocontrolled, two-period, cross-over study. Pantoprazole (40 mg) (test) or placebo (reference) were administered once daily, for 8 days, with a 3 week washout period. A single oral dose of 25 mg warfarin sodium was co-administered with pantoprazole or placebo on Day 2 of each treatment period. The 90% confidence intervals for the 'test/reference' mean ratios of the excess AUC(0,168h) of prothrombin time and AUC(0,168 h) of factor VII, and of Cmax, AUC and t112 of both R-and S-warfarin fell within the equivalence range of 80% to 125%. These results suggest that pantoprazole does not alter the pharmacokinetics or pharmacodynamics of warfarin.
Aims Triptorelin is a gonadotropin-releasing hormone (GnRH) analogue with enhanced affinity for GnRH receptors and a prolonged half-life due to its resistance to enzymatic degradation. The sustained-release formulation of this molecule is advantageous in conditions requiring chronic hormone suppression. Methods This was an open study to determine the pharmacokinetics of a single i.v. bolus dose of 0.5 mg triptorelin acetate in four groups of six male subjects; namely in healthy subjects (Group I), in patients with varying degrees of renal insufficiency (Groups II and III), and in patients with hepatic insufficiency (Group IV). Results The maximum concentrations of triptorelin were found to be similar for all four study groups (geometric mean C max between 41.6 mg ml −1 and 53.9 mg ml −1). The total clearance of triptorelin decreased with increasing renal impairment, and was even lower in patients with hepatic insufficiency (geometric mean CL tot : 210 ml min −1 , 113 ml min −1 , 86.8 ml min −1 and 57.3 ml min −1 for Groups I, II, III and IV, respectively). Serum triptorelin concentrations in all four groups were adequately described by a three-compartment model. The elimination half-life for patients with hepatic impairment was similar to that of patients with renal impairment (geometric mean t 1/2, z : 6.6 h, 7.7 h and 7.6 h for Groups II, III and IV, respectively), but significantly longer than in healthy volunteers (2.8 h for Group I). The first and second distribution half-lives were similar for the four groups studied, with geometric mean distribution half-lives of about 0.1 h (6 min) and 0.75 h (45 min), respectively. Conclusions Although both renal and hepatic function are important for the clearance of triptorelin, the liver plays the predominant role in subjects suffering from some degree of renal impairment.
Thirty-seven healthy volunteers, 19 of whom had consistently elevated total serum bilirubin (TSB) concentrations, took part in an open, randomised cross-over study to determine the effect of fasting on TSB concentrations. The study comprised of two treatments. During one treatment period volunteers ate a standard supper but fasted for 24 h thereafter. During the other treatment period volunteers ate a standard supper, snacks, breakfast and lunch. TSB concentrations were measured at regular intervals. In both the normal and high bilirubin groups, minimum TSB values were recorded 4 h after the supper. A 24 h fast more than doubled TSB concentration from baseline values in both the normal and high bilirubin groups. A clinically relevant rise in TSB took place after 12 h into the fasting period (TSB of 17.3 gmol 1-1 in the fasted group vs 14.0 gmol 1-1 in the non-fasted group). When designing a clinical trial, selecting volunteers, or judging the tolerance of a new drug, the rise in TSB caused by fasting must therefore be taken into account, particularly in trials where volunteers or patients fast before entering the study.
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