phytonadione Side Effects

What the FAERS Data Reveals About phytonadione Side Effects

The FDA Adverse Event Reporting System (FAERS) contains 8,078 voluntary reports linked to phytonadione and its brand equivalents (Vitamin K1, Mephyton), spanning 1999 through 2025. Of those, 1,508 (18.7%) listed death as an outcome and 3,758 (46.5%) involved hospitalization. The most common indication reported alongside adverse events was Product Used For Unknown Indication.

Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 53% were female and 47% male; age distribution skews toward 45-64, with 1,708 reports in that bracket. The single most reported reaction is off label use with 654 submissions, followed by nausea and vomiting.

FAERS is a signal-detection tool, not a scorecard. Reports are voluntary, and a single case may list multiple suspect drugs, so numbers above should not be read as incidence rates or per-patient risk. Widely prescribed drugs naturally accumulate more reports than niche therapies even when individual risk is low. These aggregates are useful for spotting patterns that merit further pharmacovigilance, not for choosing between medications. This page is for educational reference only and is not medical advice — speak with a licensed clinician about any side-effect concerns.