Prescription medication · Endonuclease Inhibitor (Antiviral)
baloxavir marboxil
Also sold as Xofluza. Xofluza is used to treat the flu in people 5 years and older.
Data updated 2026-05-15
- 2,164
- FDA reportsRarely reported
- 2
- InteractionsFew interactions
- $157.18
- Brand price (NADAC)
What the data shows
baloxavir marboxil (Xofluza) is a prescription Endonuclease Inhibitor (Antiviral), among the least-reported drugs the FDA tracks (2,164 FDA reports), with 2 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
baloxavir marboxil (Xofluza) is a prescription Endonuclease Inhibitor (Antiviral). Xofluza is used to treat the flu in people 5 years and older.
Xofluza is an antiviral medicine that can treat the flu. It can also prevent the flu if you have been around someone who is sick.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Brand Price
$157.18/unit
Generic Available
No
GENENTECH INC
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Xofluza is used to treat the flu in people 5 years and older.
Common side effects
Diarrhea, Bronchitis, Nausea
Key warnings
Xofluza can cause allergic reactions like anaphylaxis.
The sections below are summarized in plain English from baloxavir marboxil's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Xofluza stops the flu virus from making more copies of itself in your body. It does this by blocking a protein the virus needs to grow. This helps you get better faster or prevents you from getting sick.
Side Effects (from patient reports)
Based on 2,164 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for baloxavir marboxil, by number of reports
- Diarrhoea
Diarrhoea
129 reports
- Vomiting
Vomiting
120 reports
- Pneumonia
Pneumonia
111 reports
- Nausea
Nausea
70 reports
- Rash
Rash
61 reports
- Headache
Headache
58 reports
- Influenza
Influenza
57 reports
- Colitis Ischaemic
Colitis Ischaemic
56 reports
- Hyperpyrexia
Hyperpyrexia
54 reports
- Pyrexia 51
Pyrexia
51 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for baloxavir marboxil each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where baloxavir marboxil sits
baloxavir marboxil has more FDA adverse-event reports than 13% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is baloxavir marboxil; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 2,164 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2017–2025.
Total Reports
2,164
Reports Mentioning Death
130
6.0% of reports — not proof of cause
Hospitalization Reports
417
Top Indication
Influenza
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 4 | DIARRHOEA | 129 |
| 5 | VOMITING | 120 |
| 6 | PNEUMONIA | 111 |
| 8 | NAUSEA | 70 |
| 9 | RASH | 61 |
| 10 | HEADACHE | 58 |
| 11 | INFLUENZA | 57 |
| 12 | COLITIS ISCHAEMIC | 56 |
| 13 | HYPERPYREXIA | 54 |
| 14 | PYREXIA | 51 |
| 15 | URTICARIA | 42 |
| 16 | COUGH | 40 |
| 17 | ANAPHYLACTIC REACTION | 38 |
| 18 | DIZZINESS | 38 |
| 19 | LOSS OF CONSCIOUSNESS | 38 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Xofluza can cause allergic reactions like anaphylaxis. Get medical help right away if you have trouble breathing, hives, or swelling. Xofluza is not for children under 5 years old because it may not work as well in this age group. Xofluza does not prevent bacterial infections, which can happen with the flu. See a doctor if you think you have a bacterial infection.
Known Drug Interactions
7 DRUG INTERACTIONS Avoid coadministration of XOFLUZA with dairy products, calcium-fortified beverages, polyvalent cation-containing laxatives, antacids, or oral supplements (e.g., calcium, iron, magnesium, selenium, or zinc). Avoid coadministration of XOFLUZA with dairy products, calcium-fortified beverages, polyvalent cation-containing laxatives, antacids, or oral supplements (e.g., calcium, iron, magnesium, selenium, or zinc).
Mechanism: Zinc can bind to this medicine in your stomach and prevent it from being absorbed into your body. This makes the medicine less effective at treating the flu.
7 DRUG INTERACTIONS Avoid coadministration of XOFLUZA with dairy products, calcium-fortified beverages, polyvalent cation-containing laxatives, antacids, or oral supplements (e.g., calcium, iron, magnesium, selenium, or zinc). Avoid coadministration of XOFLUZA with dairy products, calcium-fortified beverages, polyvalent cation-containing laxatives, antacids, or oral supplements (e.g., calcium, iron, magnesium, selenium, or zinc).
Mechanism: Selenium can attach to the medicine in your digestive system and stop it from getting into your bloodstream. This prevents the drug from working correctly.
This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.
Common Questions
How quickly does Xofluza work?
Can I take Xofluza if I'm allergic to eggs?
Can Xofluza prevent me from spreading the flu to others?
Can I take Xofluza with other medicines?
What if I start feeling worse after taking Xofluza?
Is there a generic version of Xofluza?
How effective is Xofluza?
Can I get the flu again even if I take Xofluza?
Does Xofluza interact with the flu shot?
What should I do if someone in my family has the flu?
What are the common side effects of baloxavir marboxil?
Does baloxavir marboxil interact with other medications?
What drug class is baloxavir marboxil?
What pregnancy or breastfeeding source fields are listed for baloxavir marboxil?
Related Medications in Endonuclease Inhibitor (Antiviral)
Other drugs grouped near baloxavir marboxil - same-class peers and common alternatives.
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Compare beyond drug class
Nationwide peers by FAERS volume & death-report share
Two PlainMeds-derived comparison paths for baloxavir marboxil: nearest FDA FAERS report volume and nearest death-report share among drugs with at least 1,000 logged reports, excluding same-class neighbors listed above. Counts reflect reporting volume, not proven individual harm.
Similar FAERS report volume
Nearest drugs by total FAERS reports. This record: 2,164.
Similar death-report share
Nearest drugs by FAERS death-report share. This record: 6.01%.
- rosuvastatin Δ 0.01 pts · 194,743 reports · HMG-CoA Reductase Inhibitor (Statin) 6.02%death share
- chlorthalidone Δ 0.06 pts · 11,035 reports · Thiazide-Like Diuretic 5.94%death share
- dicyclomine Δ 0.10 pts · 13,367 reports · Anticholinergic / Antispasmodic 5.91%death share
- zonisamide Δ 0.11 pts · 14,210 reports · Anticonvulsant (Sulfonamide) 6.12%death share
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What the FDA Data Shows for baloxavir marboxil
The FDA label for baloxavir marboxil (sold under brand names such as Xofluza) classifies it as a prescription-only medication in the Endonuclease Inhibitor (Antiviral) class. Xofluza is used to treat the flu in people 5 years and older. Official labeling lists 6 commonly reported side effects, including Diarrhea, Bronchitis, Nausea.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 2,164 voluntary reports. The database also lists 2 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.
Last updated: August 22, 2025
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages