Tamiflu and Eliquis Interaction Assessment

Pharmacokinetics and Pharmacodynamics

Oseltamivir is primarily metabolized by hepatic esterases to its active form, oseltamivir carboxylate, with minimal CYP450 involvement in its metabolism, according to the Centers for Disease Control and Prevention (CDC) 1
Approximately 80% of oseltamivir is absorbed systemically and excreted renally via glomerular filtration and tubular secretion through the anionic pathway, as recommended by the CDC 1, 3
Apixaban is primarily metabolized via hepatic CYP3A4-dependent pathways, with only 27% undergoing renal elimination, and is a substrate for P-glycoprotein (P-gp) transporter, as stated by the American Heart Association (AHA) 4, 5
Apixaban has an apparent half-life of approximately 12 hours, according to the National Comprehensive Cancer Network (NCCN) 4

Oseltamivir does not inhibit or induce CYP3A4, which is the primary metabolic pathway for apixaban, as reported by the CDC and the AHA 1, 5
Oseltamivir is not a P-gp inhibitor or inducer, so it does not affect apixaban transport, according to the AHA 5
Probenecid is the only documented interaction with oseltamivir, reducing oseltamivir carboxylate clearance by ~50% through competition for renal tubular secretion, as stated by the CDC 3
Strong dual CYP3A4 and P-gp inhibitors (e.g., ketoconazole, clarithromycin, ritonavir) require a 50% reduction in apixaban dose, while strong dual CYP3A4 and P-gp inducers (e.g., rifampin, carbamazepine, phenytoin) should be avoided due to reduced apixaban efficacy, as recommended by the AHA 5

No special monitoring or dose adjustments are required when prescribing oseltamivir to patients taking apixaban, according to the CDC and the AHA 1, 5
Renal function assessment is necessary for both drugs, with oseltamivir requiring a reduced dose of 75 mg once daily for CrCl 10-30 mL/min, and apixaban being avoided if CrCl <15 mL/min, as stated by the CDC, the NCCN, and the American College of Cardiology (ACC) 1, 4, 6
Gastrointestinal tolerability can be improved by administering oseltamivir with food, which does not affect absorption, as reported by the CDC and the ACC 3, 6
Bleeding risk considerations require monitoring for bleeding if the patient develops severe influenza-related complications that could independently affect coagulation, according to the NCCN 4