In vivo metabolism of fondaparinux has not been investigated since the majority of the administered dose is eliminated unchanged in urine in individuals with normal kidney function.
Fondaparinux therapy is associated with a low rate of serum aminotransferase elevations during therapy, with levels above 3 times the upper limit of normal occurring in 1% to 3% of patients, a lower rate than occurs with heparin (~8%) or low molecular weight heparins (4% to 12%) but higher than occurs with placebo (
◉ Summary of Use during Lactation:Fondaparinux is considered to be acceptable to use during breastfeeding.
◉ Effects in Breastfed Infants:Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk:Relevant published information was not found as of the revision date.
To investigate the in vitro metabolism of the antithrombotic agent fondaparinux sodium in mammalian liver fractions and to evaluate its potential inhibitory effect on human cytochrome P450 (CYP)-mediated metabolism of other drugs. Metabolism was evaluated by incubating radioisotope-labelled fondaparinux sodium with postmitochondrial liver fractions of rat, rabbit, monkey or human origin (three subjects). Human liver microsomal preparations and an NADPH-generating system were incubated with phenacetin, coumarin, tolbutamide, S-mephenytoin, bufuralol, chlorzoxazone or nifedipine. These are selectively metabolised by CYP isoforms: CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2D6, CYP2E1 or CYP3A4, respectively. Experiments were designed to determine apparent K(i) (inhibitory constant) values for fondaparinux sodium against each CYP isoform, by varying concentrations of fondaparinux sodium and the selective substrate. Each experiment included control reaction mixtures containing an isoform-selective inhibitor. After incubation, the mixtures were analysed by LC-MS/MS or with fluorometric detection. All liver fractions were enzymatically active, as demonstrated by degradation of [(14)C]testosterone. No metabolism of fondaparinux sodium was detectable in postmitochondrial liver fractions. Apparent K(i) values for fondaparinux sodium against the CYP isoforms could not be determined because the oxidative metabolism of the isoform-selective CYP substrates was not significantly inhibited in pooled microsomal reaction mixtures. In the presence of selective CYP inhibitors, metabolism of each substrate was significantly reduced, confirming that inhibition could be observed in these assays. The demonstrated lack of mammalian hepatic metabolism of fondaparinux sodium is consistent with animal and human studies. The absence of inhibition of the human CYP isoforms commonly involved in the metabolism of drugs suggests that clinical treatment with fondaparinux sodium is unlikely to interfere with the pharmacokinetics and metabolism of a wide range of other drugs which are associated with CYP inhibition.
... Two separate studies assessed any possible interaction between fondaparinux sodium at steady state and aspirin (acetylsalicylic acid) or piroxicam in healthy volunteers. In the first study a single dose of aspirin 975mg was assessed initially, followed by single doses of aspirin or placebo on the fourth day of an 8-day regimen of subcutaneous fondaparinux sodium (10mg once daily). The second study was a three-way crossover, double-blind, randomised study which investigated fondaparinux sodium 10mg + placebo, fondaparinux sodium 10mg + piroxicam 20mg, or placebo + piroxicam 20mg. ... Neither aspirin nor piroxicam influenced the pharmacokinetics of fondaparinux sodium at steady state. Two hours after administration, prolongation of bleeding time with aspirin alone or with aspirin plus fondaparinux sodium was significantly greater than with fondaparinux sodium alone (p = 0.003 and p = 0.004, respectively). No significant differences were observed between aspirin alone or aspirin + fondaparinux sodium in effect on bleeding time. A small decrease in collagen-induced platelet aggregation was observed after administration of piroxicam alone or piroxicam + fondaparinux sodium. A small effect on aPTT was observed; it was similar for fondaparinux sodium whether administered alone or in combination with either aspirin or piroxicam. No serious adverse events were reported.
... In this study /investigators/ assessed the possible pharmacokinetic and pharmacodynamic interaction of fondaparinux sodium with digoxin at steady state in healthy male volunteers. In a phase I randomised, crossover study, volunteers (n = 24) were treated in two periods. The first period was once-daily administration of fondaparinux sodium 10mg subcutaneously alone for 7 days; the second period was 7 days of digoxin 0.25mg orally alone followed by 7 days of coadministration with fondaparinux sodium 10mg. Each period was separated by a washout of 12 days. ... The pharmacokinetic profiles of both digoxin and fondaparinux sodium were unaffected by coadministration. Bioequivalence was concluded, based on the 90% confidence intervals of the ratio of adjusted geometric means calculated for the 2-by-2 comparison of peak concentration, area under the concentration-time curve and cumulative urinary excretion, which lay within the 0.80 to 1.25 reference interval. There were no clinically significant fluctuations in vital signs and ECG parameters. The coadministration of digoxin with fondaparinux sodium was well tolerated and no significant changes were observed in vital signs.
Following a single subcutaneous dose of fondaparinux sodium 2.5 mg in young male subjects, Cmax of 0.34 mg/L is reached in approximately 2 hours. In patients undergoing treatment with fondaparinux sodium injection 2.5 mg, once daily, the peak steady-state plasma concentration is, on average, 0.39 to 0.50 mg/L and is reached approximately 3 hours post-dose. In these patients, the minimum steady-state plasma concentration is 0.14 to 0.19 mg/L. In patients with symptomatic deep vein thrombosis and pulmonary embolism undergoing treatment with fondaparinux sodium injection 5 mg (body weight <50 kg), 7.5 mg (body weight 50 to 100 kg), and 10 mg (body weight >100 kg) once daily, the body-weight-adjusted doses provide similar mean steady-state peaks and minimum plasma concentrations across all body weight categories. The mean peak steady-state plasma concentration is in the range of 1.20 to 1.26 mg/L. In these patients, the mean minimum steady-state plasma concentration is in the range of 0.46 to 0.62 mg/L.
作者:Jessica M. Christian、Mary Zoepfl、Wyatt E. Johnson、Eric Ginsburg、Erica J. Peterson、J. David Hampton、Nicholas P. Farrell
DOI:10.1016/j.jinorgbio.2023.112254
日期:2023.8
The Co complexes were chosen to be formally substitution-inert and/or have the potential for covalent binding to the biomolecule. Using both indirect competitive inhibition assays and direct mass spectrometric assays, formally substitution-inert complexes bound to FPX with protection from multiple sulfate loss in the gas phase through metalloshielding. Covalent binding of Co-Cl complexes as in [CoCl(NH3)5]2+