Drug side effects
baloxavir marboxil Side Effects
The reactions most often reported to the FDA for baloxavir marboxil (also sold as Xofluza), with demographics, serious outcomes, and reporting trends.
Data updated 2026-05-15
- 2,164
- FAERS reports
Data from the FDA Adverse Event Reporting System (FAERS), 2017 to 2025. A FAERS report records a temporal association, not proof of cause. See our methodology for how figures are compiled and de-duplicated.
The most commonly reported side effects of baloxavir marboxil come from 2,164 reports to the FDA, broken down here by frequency, patient demographics, and serious outcomes.
This page analyzes 2,164 reports to the FDA Adverse Event Reporting System (FAERS) for baloxavir marboxil (Xofluza): the reactions reported most often, who reported them, serious outcomes such as hospitalization, and year-over-year trends. A FAERS report does not prove the drug caused the effect, and report volume tracks how widely a drug is used, not how likely an effect is for any one person. Educational information, not medical advice.
Total Reports
2,164
Reports Mentioning Death
130
6.0% of reports — not proof the medicine caused the death
Hospitalizations
417
19.3% of reports
Top Indication
Influenza
Most Reported Adverse Reactions
Who Reports Side Effects
Gender Distribution
Age Distribution
Reporting Trend by Year
Reactions in Death Reports
Top reactions reported in 130 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| DEATH | 32 |
| PNEUMONIA | 18 |
| INFLUENZA | 10 |
| RESPIRATORY FAILURE | 9 |
| CARDIO-RESPIRATORY ARREST | 7 |
| MULTIPLE ORGAN DYSFUNCTION SYNDROME | 7 |
| ACUTE KIDNEY INJURY | 6 |
| ACUTE RESPIRATORY DISTRESS SYNDROME | 5 |
| DISSEMINATED INTRAVASCULAR COAGULATION | 5 |
| INFECTION | 5 |
| SEPSIS | 5 |
| CARDIAC FAILURE | 4 |
| DECREASED APPETITE | 4 |
| PNEUMONIA INFLUENZAL | 4 |
| ACUTE RESPIRATORY FAILURE | 3 |
| ALANINE AMINOTRANSFERASE INCREASED | 3 |
| BRAIN HERNIATION | 3 |
| CIRCULATORY COLLAPSE | 3 |
Reactions in Hospitalization Reports
Top reactions in 417 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| PNEUMONIA | 52 |
| DIARRHOEA | 29 |
| COLITIS ISCHAEMIC | 25 |
| VOMITING | 24 |
| RHABDOMYOLYSIS | 17 |
| ANAPHYLACTIC REACTION | 14 |
| PYREXIA | 13 |
| ABDOMINAL PAIN | 12 |
| DRUG ERUPTION | 12 |
| ABNORMAL BEHAVIOUR | 11 |
| ACUTE KIDNEY INJURY | 11 |
| DECREASED APPETITE | 11 |
| HEPATIC FUNCTION ABNORMAL | 11 |
| RASH | 11 |
| SEIZURE | 11 |
| DYSPNOEA | 10 |
| SEPSIS | 10 |
| HAEMATOCHEZIA | 9 |
Nearby, Related Medications
What the FAERS Data Reveals About baloxavir marboxil Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 2,164 voluntary reports linked to baloxavir marboxil and its brand equivalents (Xofluza), spanning 2017 through 2025. Of those, 130 (6.0%) listed death as an outcome and 417 (19.3%) involved hospitalization. The most common indication reported alongside adverse events was Influenza.
Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 54% were female and 46% male; age distribution skews toward 0-17, with 619 reports in that bracket. The single most reported reaction is diarrhoea with 129 submissions, followed by vomiting and pneumonia.
How to read these numbers
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.
Drugs With a Similar FAERS Report Volume
Other medications with a total FDA adverse-event report count closest to baloxavir marboxil's 2,164.
Read our methodology - how this data is sourced, computed, and verified.