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Baloxavir Side Effects

The most commonly reported side effects of baloxavir include no adverse event, off label use, and intentional product use issue, based on 2,171 FDA adverse event reports from 2018 to 2025. 4.1% of reports found the drug to be ineffective.

Baloxavir side effects

Percentages show how often each reaction appears relative to total reports for baloxavir.

1
No Adverse Event23.9%518
2
Off Label Use19.3%419
3
Intentional Product Use Issue13.0%283
4
Diarrhoea5.9%129
5
Vomiting5.5%120
6
Pneumonia5.1%111
7
Drug Ineffective4.1%88
8
Nausea3.2%70
9
Rash2.8%61
10
Influenza2.7%59
11
Headache2.7%58
12
Colitis Ischaemic2.6%56
13
Hyperpyrexia2.5%54
14
Pyrexia2.3%51
15
Urticaria1.9%42

These are voluntary reports and do not establish that baloxavir caused these reactions.

Report severity

52.4%Serious1,138 reports
19.5%Hospitalizations423 reports
6.0%Fatal131 reports

Seriousness is determined by the reporter, not by OpenClaim.

Baloxavir drug interactions

Other drugs that appear in adverse event reports alongside baloxavir. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Oseltamivir-phosphate5.1%111
2
Acetaminophen0.6%14
3
Warfarin0.4%9
4
Methylprednisolone0.4%9
5
Tobramycin0.4%8
6
Prednisone0.3%7
7
Dextromethorphan0.3%7
8
Doxycycline0.3%7
9
Cefiderocol-sulfate-tosylate0.3%7
10
Posaconazole0.3%7
11
Ganciclovir0.3%7
12
Mycophenolate0.3%6
13
Cyclosporine0.3%6
14
Cyclophosphamide0.2%5
15
Tranexamic-acid0.2%5

Taken alongside

1
Acetaminophen3.1%67
2
Ibuprofen1.6%35
3
Dextromethorphan1.6%34
4
Cysteine-hydrochloride1.6%34
5
Amlodipine1.5%32
6
Prednisone1.2%26
7
Levofloxacin0.9%20
8
Oseltamivir-phosphate0.8%18
9
Rosuvastatin0.8%18
10
Atorvastatin-calcium0.8%18
11
Methylprednisolone0.8%18
12
Omeprazole0.8%17
13
Aspirin0.7%16
14
Montelukast-sodium0.7%16
15
Furosemide0.7%16

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports baloxavir side effects

42.1% of baloxavir adverse event reports involve female patients and 35.7% involve male patients. The largest age group is adult at 42%. These figures reflect who reports side effects, not underlying risk.

Sex

Female42.1%
Male35.7%
Unknown22.3%

Age group

< 20.3%
2–1127.0%
12–179.0%
18–6441.5%
65+22.1%

What is baloxavir used for

Conditions and purposes for which patients were taking baloxavir when the adverse event was reported.

Angina PectorisAntiviral ProphylaxisAntiviral ProphylaxisAntiviral TreatmentAsthmaAvian InfluenzaBacterial InfectionBronchitis ViralBronchopulmonary AspergillosisCovid-19Chronic Obstructive Pulmonary DiseaseDiarrhoeaFebrile InfectionGastrointestinal DisorderH1n1 Influenza

Showing 15 of 53 indications

Baloxavir brand names and reporting trend

Baloxavir is sold under the brand name Xofluza.

Brand names

Xofluza124

Quarterly reports (20182025)

20182020202220242025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking baloxavir with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.