No Clinically Significant Interaction Between Tamiflu and Eliquis
There is no clinically significant drug interaction between Tamiflu (oseltamivir) and Eliquis (apixaban), and no dose adjustments or special monitoring are required when these medications are prescribed together. 1
Pharmacologic Basis for Lack of Interaction
The absence of interaction is explained by the distinct metabolic pathways of these two drugs:
Oseltamivir does not affect apixaban metabolism because it neither inhibits nor induces CYP3A4, which is the primary hepatic enzyme responsible for metabolizing apixaban 1
Oseltamivir does not affect apixaban transport as it is not a P-glycoprotein (P-gp) inhibitor or inducer, and apixaban is a substrate for this transporter 1
Oseltamivir is primarily eliminated renally (approximately 80% via glomerular filtration and tubular secretion through the anionic pathway) with minimal CYP450 involvement, while apixaban undergoes predominantly hepatic metabolism via CYP3A4 with only 27% renal elimination 1
The only documented drug interaction with oseltamivir is probenecid, which reduces oseltamivir carboxylate clearance by approximately 50% through competition for renal tubular secretion 1
Clinical Management Recommendations
When prescribing these medications together, follow this straightforward approach:
No dose adjustments are needed for either oseltamivir or apixaban when used concomitantly 1
Assess renal function for both medications, as this is the only parameter requiring attention:
Administer oseltamivir with food to improve gastrointestinal tolerability without affecting drug absorption 1
Monitor for bleeding only if severe influenza complications develop that could independently affect coagulation status, not because of any drug-drug interaction 1
Important Caveat: Warfarin vs. Apixaban
A critical distinction must be made regarding anticoagulant class:
Oseltamivir has been reported to interact with warfarin (a vitamin K antagonist), causing elevated INR and bleeding complications, particularly in patients with renal insufficiency 2, 3
This warfarin interaction does NOT apply to apixaban (a direct oral anticoagulant), which has an entirely different mechanism of action and metabolic profile 1
Emergency physicians and primary care providers should be aware that while close INR monitoring is recommended when oseltamivir is given with warfarin 3, no such monitoring is required with apixaban 1