Drug Interactions between drotrecogin alfa and Yosprala

MONITOR CLOSELY: Coadministration of drotrecogin alfa and other drugs that interfere with coagulation or platelet function may potentiate the risk of bleeding complications. Drotrecogin alfa inactivates blood clotting factors Va and VIIIa and may prolong the activated partial thromboplastin time (APTT). Treatment with drotrecogin alfa alone has been associated with serious and life-threatening bleeding episodes, including gastrointestinal, intracranial and retroperitoneal hemorrhage, although most severely ill septic patients are already at a high risk of bleeding because of coagulopathies associated with prolonged APTT and prothrombin time (PT). In a phase 3 study, the incidence of serious bleeding events during the 28-day study period was 3.5% for drotrecogin alfa versus 2.0% for placebo, with the difference occurring primarily during the infusion period.

MANAGEMENT: The potentially increased risk of bleeding versus the benefits of drotrecogin alfa therapy should be carefully considered in seriously ill septic patients who have recently (within 7 days) received oral anticoagulants, platelet inhibitors, or aspirin (more than 650 mg/day). Close clinical and laboratory monitoring for bleeding complications is recommended if concurrent therapy is required. Drotrecogin alfa should be discontinued immediately if clinically significant bleeding occurs. Continued use of other agents that may have contributed to the bleeding should be carefully assessed. Once adequate hemostasis is attained, drotrecogin alfa may be resumed if necessary.

Coadministration with proton pump inhibitors may decrease the oral bioavailability of aspirin and other salicylates. The interaction has been studied with omeprazole and aspirin, although data are conflicting. In one study, pretreatment with omeprazole (20 mg/day for 2 days) in 11 healthy volunteers led to a significant and progressively greater reduction in the mean serum salicylate level at 30, 60, and 90 minutes after administration of aspirin (650 mg single dose). The investigators suggest that acid suppression may reduce the lipophilic nature of aspirin, thereby adversely affecting its absorption from the gastrointestinal tract. Another study found no effect of omeprazole pretreatment (20 mg/day for 4 days) on plasma salicylate and aspirin levels, skin bleeding times, or antiplatelet effect of low-dose aspirin (125 mg single dose) in 14 healthy volunteers. However, these results do not exclude the possibility that omeprazole might interfere with the analgesic, antipyretic, or anti-inflammatory effects of aspirin, which has been demonstrated in rats.

Proton pump inhibitors may enhance the release rate of salicylates from enteric-coated formulations due to premature disruption of the coating and intragastric release of the drug secondary to an increase in gastric pH. In eight healthy volunteers, omeprazole pretreatment (20 mg/day for 4 days) did not affect the bioavailability of salicylate from uncoated aspirin tablets but significantly increased the absorption rate of salicylate from enteric-coated sodium salicylate tablets. The clinical significance of this interaction is unknown. Theoretically, it may increase the risk of gastric adverse effects associated with salicylates.