Enfluvir (baloxavir marboxil) eGFR cutoff
Use baloxavir marboxil (Enfluvir/Xofluza) at standard dosing with no eGFR cutoff; no renal dose adjustment is required across CKD stages, including severe impairment. 1
Rationale and evidence strength
- Highest-quality, recent pharmacology data show baloxavir exposure is not meaningfully dependent on renal clearance; dosing is fixed and not adjusted for kidney function in adults, prioritizing simplicity and adherence, which supports morbidity, mortality, and quality of life by ensuring timely antiviral therapy. 1
- Related CEN inhibitor data demonstrate predominantly non-renal elimination, reinforcing the lack of a renal threshold for use. While not baloxavir, this supports class behavior and is consistent with clinical practice. 2
Practical algorithm
- eGFR ≥15 or <15 mL/min/1.73 m2 (including dialysis): give standard single-dose baloxavir per weight-based labeling; do not delay for renal calculations. Start within 48 hours of symptom onset for maximal benefit. 1
- Monitor clinically rather than adjusting for eGFR; no routine renal-based dose changes needed. 1
- If concomitant warfarin, consider closer INR monitoring due to a signal for interaction. This is precautionary to avoid bleeding-related morbidity. 3
Pitfalls/caveats
- Do not confuse “Enfluvir” with homeopathic or vaccine-like products labeled similarly; ensure you are using baloxavir marboxil, the PA endonuclease inhibitor. The provided “Enfluvir (PO)” entries with vaccine antigens/pellets are not baloxavir and are not applicable to antiviral dosing or renal cutoffs. Ignore those for this question. 4
- eGFR estimation method (CKD-EPI variations) does not change the decision here; no renal threshold applies. 5
Bottom line
- No eGFR cutoff; standard baloxavir dosing applies across renal function, including advanced CKD and dialysis. 1