(14)C-eptifibatide was extensively metabolized to deamidated eptifibatide and to several polar metabolites by both rats and monkeys. The drug-derived radioactivity excreted into the bile by rats, and identified as deamidated eptifibatide, was reabsorbed from the intestinal tract and further metabolized to more polar metabolites. The plasma and urine metabolite profiles in rats and monkeys indicate that the metabolic disposition of eptifibatide is similar for the two species.
Eptifibatide is metabolized principally through deamidation to a metabolite that has approximately 41% of the platelet-aggregation inhibitory activity of the parent compound, and through formation of other more polar metabolites. Approximately 27% of a dose of eptifibatide is broken down in plasma into naturally occurring amino acids; no major non-amino acid metabolites have been detected in plasma in humans.
IDENTIFICATION AND USE: Eptifibatide, as the drug Integrilin, is indicated to decrease the rate of a combined endpoint of death, new myocardial infarction (MI), or need for urgent intervention in patients undergoing percutaneous coronary intervention (PCI), including those undergoing intracoronary stenting. HUMAN EXPOSURE AND TOXICITY: Limited information is available on the acute toxicity of eptifibatide. In general, overdosage of eptifibatide in humans may be expected to produce effects that are extensions of the pharmacologic effects of the drug, predominantly bleeding. There have been cases of eptifibatide associated thrombocytopenia, which reinforces the importance of platelet count monitoring after therapy with this agent. Eptifibatide was not genotoxic in the human lymphocyte chromosome aberrations test. ANIMAL STUDIES: Single dose toxicity studies were conducted in rats, rabbits and monkeys; doses up to 500 ug/kg/minute administered by continuous intravenous infusion for 90 minutes did not cause mortality and were well-tolerated by all species. In rabbits, a dose-dependent decrease in platelet counts of the 50 and 500 ug/kg/minute (for 90 minutes)-dosed females was attributed to administration of eptifibatide. Findings in the monkeys were limited to petechial hemorrhages in the femoral and/or abdominal regions, which lasted for one to three days. Three out of five monkeys died or were sacrificed during the study due to contusions, excessive bleeding and/or petechial hemorrhages, which resulted in anemia. Total protein albumin and globulin values were reduced in all monkeys. At necropsy, focal hemorrhages in various organs were observed. In a fertility study in rats, dosing with eptifibatide had no effect on the course of pregnancy. No evidence of fertility or parental toxicity nor effects upon parental reproductive performance were observed at daily doses up to 72.0 mg/kg (24 times the maximum recommended daily human dose). Eptifibatide was not genotoxic in the Ames assay at doses up to 667 ug/mL, in the mouse lymphoma cell forward mutation assay at doses up to 1,000 ug/mL, or in the mouse micronucleus test.
◉ Summary of Use during Lactation:No published information is available on the use of eptifibatide during breastfeeding. Because eptifibatide is a peptide, absorption by the infant is unlikely because it is probably destroyed in the infant's gastrointestinal tract. Until more data become available, eptifibatide should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. If it is used by a nursing mother, monitor the infant for bruising and bleeding.
◉ 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.
Concomitant use of platelet-aggregation inhibitors and an anticoagulant (particularly in high dosages) may increase the risk of hemorrhage, and careful monitoring for bleeding is necessary, especially at arterial puncture sites. Eptifibatide and concomitant heparin therapy should be discontinued immediately and appropriate therapy (e.g., protamine sulfate in patients receiving heparin) instituted as necessary if serious bleeding occurs (e.g., bleeding not controlled by pressure). In healthy individuals, enoxaparin sodium (1 mg/kg subcutaneously every 12 hours for 4 doses) did not alter the pharmacokinetics or pharmacodynamics (platelet aggregation) of eptifibatide. The manufacturer states that caution should be employed when using eptifibatide with oral anticoagulants.
Eptifibatide has been administered concomitantly with thrombolytic agents (e.g., alteplase, streptokinase, tenecteplase) in a limited number of patients with acute myocardial infarction to reduce the risk of reocclusion of the infarct-related artery. Some clinicians suggest that use of short-acting platelet-aggregation inhibitors such as eptifibatide concomitantly with thrombolytic therapy may provide optimal benefit while minimizing the risk of bleeding However, use after thrombolysis of drugs that affect platelet function may increase the risk of bleeding complications, including those requiring blood transfusions, associated with thrombolytic therapy and has not been shown to be unequivocally effective to date; therefore, use of eptifibatide with thrombolytic therapy should be considered investigational and should be undertaken with caution.
