Reported Reactions

Drugs › Opioid antagonist

Generic name

Naloxone: adverse event reports filed with FDA

1,693 reports list it as a suspect or interacting product, 2004–2026. Class: Opioid antagonist.

1,693
reports as suspect product
0% of all reports · about 76 a year
129
reports, 12 months to June 2026
285 in the 12 months before
94.2%
marked serious by the reporter
62.4% across the class
35%
record death among outcomes, as reported
592 reports · not verified by FDA

Between February 2004 and June 2026, 1,693 adverse event reports received by FDA list naloxone, a generic name as a suspect or interacting product. Reports that mention it only as a concomitant medication (3,114) are left out of every figure here.

In the 12 months to June 2026, 129 reports listed it, down 55% from 285 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 76 reports a year and 0% of the 20,646,523 reports in the database, and 5.4% of the reports for the opioid antagonist class. How many people take it is not in the data, so a count is not a rate of occurrence.

Reporters most often recorded toxicity to various agents (29.2%), drug ineffective (19.1%) and overdose (16.2%). A report can list several reactions, so shares add to more than 100%; 434 different terms appear across these reports. Toxicity to various agents is recorded in 29.2% of these reports, a larger share than in the median opioid antagonist drug (1.4%).

94.2% of the reports are marked serious by the reporter (62.4% across the class); 35% record death among the outcomes and 49.2% record hospitalisation, as reported. 55.3% of the reports came from other health professionals, and the largest patient age group is 18 to 44 (33.7%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

Reports by month, five years

02753Jul 2021: 9Aug 2021: 22Sep 2021: 23Oct 2021: 11Nov 2021: 21Dec 2021: 132022Jan 2022: 9Feb 2022: 20Mar 2022: 8Apr 2022: 3May 2022: 5Jun 2022: 32Jul 2022: 22Aug 2022: 3Sep 2022: 5Oct 2022: 13Nov 2022: 15Dec 2022: 22023Jan 2023: 4Feb 2023: 14Mar 2023: 45Apr 2023: 14May 2023: 15Jun 2023: 8Jul 2023: 5Aug 2023: 6Sep 2023: 19Oct 2023: 27Nov 2023: 16Dec 2023: 72024Jan 2024: 7Feb 2024: 14Mar 2024: 13Apr 2024: 6May 2024: 49Jun 2024: 34Jul 2024: 35Aug 2024: 23Sep 2024: 19Oct 2024: 31Nov 2024: 53Dec 2024: 192025Jan 2025: 10Feb 2025: 28Mar 2025: 17Apr 2025: 18May 2025: 18Jun 2025: 14Jul 2025: 17Aug 2025: 18Sep 2025: 10Oct 2025: 6Nov 2025: 13Dec 2025: 92026Jan 2026: 10Feb 2026: 11Mar 2026: 8Apr 2026: 6May 2026: 7Jun 2026: 14

Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

By year received

01523032004: 820042005: 62006: 82007: 720072008: 72009: 192010: 1920102011: 212012: 292013: 3720132014: 352015: 312016: 2720162017: 672018: 582019: 7520192020: 2072021: 1782022: 13720222023: 1802024: 3032025: 17820252026: 56

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Naloxone reports recording the termmedian drug in opioid antagonist

  1. Toxicity to various agentspoisoning or toxic effect of one or more substances29.2%494
  2. Drug ineffectivethe medicine did not work as expected19.1%323
  3. Overdosea dose above the recommended amount16.2%275
  4. Drug abusemisuse of a medicine5.4%91
  5. Drug dependencedependence on a medicine5.3%89
  6. Cardiac arrestthe heart stopped4.9%83
  7. Respiratory depressionslow or shallow breathing4.9%83
  8. Hypotensionlow blood pressure4.8%82
  9. Off label useused for a purpose or in a way not on the label4.7%80
  10. Pulmonary oedemafluid in the lungs4.6%78
  11. Deaththe patient died; cause not stated by this term4.5%77
  12. Maternal exposure during pregnancythe mother took the medicine during pregnancy4.4%75
  13. Drug interactionan interaction between medicines4.2%71
  14. Coma4.1%69
  15. Drug withdrawal syndromesymptoms on stopping a medicine4%68
  16. Foetal exposure during pregnancythe unborn baby was exposed to the medicine3.9%66
  17. Somnolencedrowsiness3.8%65
  18. Intentional overdosea deliberate overdose2.7%46
  19. Premature babya baby born early2.7%45
  20. Suicide attempta suicide attempt2.7%45
  21. Vomitingbeing sick2.6%44
  22. Electrocardiogram QT prolongeda QT prolongation on the ECG2.5%42
  23. Agitationrestlessness2.4%41
  24. Respiratory failurethe lungs could not supply enough oxygen2.4%41
  25. Acute kidney injurysudden loss of kidney function2.3%39
  26. Bradycardiaslow heart rate2.2%38
  27. Miosis2.2%37
  28. Hypertensionhigh blood pressure2.1%35

Top 30 of 434 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 10 drugs in the opioid antagonist class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Outcomes recorded

Death35%592
Life-threatening19.7%334
Hospitalisation (initial or prolonged)49.2%833
Disability1.5%25
Congenital anomaly0.2%4
Other serious47.9%811
Not serious5.8%98

Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 31,239 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."

Patients and reporters

Patient age

Under 21.7%29
2 to 111.8%31
12 to 172.6%44
18 to 4433.7%571
45 to 6426.3%445
65 to 746.8%115
75 and over4.5%76
Age not given22.6%382

Patient sex

Female39.6%670
Male47.8%810
Not given12.6%213

Who reported

Physician23.3%394
Pharmacist4.8%81
Other health professional55.3%936
Lawyer0.9%16
Consumer or non-health professional12%204
Not given3.7%62

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 53% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Toxicity to various agents1187%
Overdose824.8%
Respiratory depression553.2%
Drug use disorder362.1%
Pain311.8%
Substance use disorder281.7%

The indication field is filled in by the reporter and is often blank; shares are of all 1,693 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Naloxone reports
Fentanyl49028.9%
Buprenorphine25314.9%
Caffeine20412%
Diazepam17310.2%
Methamphetamine16910%
Nicotine1317.7%
Methadone1277.5%
Gabapentin1227.2%
Oxycodone1227.2%
Acetaminophen1197%

Other products listed in reports where Naloxone is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.

In context

MeasureNaloxoneOpioid antagonistAll reports
Reports as suspect product1,69331,23920,646,523
Share of that pool—5.4%0%
Reports, latest 12 months129—1,332,454
Marked serious94.2%62.4%57.4%
Death recorded among outcomes, per 1,000 reports3508791
Hospitalisation recorded, per 1,000 reports492204213
Consumer-filed share12%48.6%45.8%
Top term, share of reportsToxicity to various agents 29.2%median 1.4%0.8%

Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Other drugs in the opioid antagonist class

DrugName typeReportsLatest 12 monthsMarked serious
Suboxonebrand20,91955266.8%
Movantikbrand1,9974526.9%
Buprenorphine and naloxonegeneric1,9356653.7%
Relistorbrand9782855.4%
Zubsolvbrand9734421%
Narcanbrand8353856.2%
Buprenorphine hydrochloride, naloxone hydrochloridegeneric8247757.9%
Symproicbrand5481347.3%
Naloxone hydrochloridegeneric5376173.4%

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.

Questions about Naloxone reports

How many adverse event reports has FDA received for Naloxone?

1,693 reports list Naloxone as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 129 of them arrived in the latest 12 months. Another 3,114 list it only as a concomitant medication.

What reactions are recorded in Naloxone reports?

toxicity to various agents (29.2%), drug ineffective (19.1%), overdose (16.2%), drug abuse (5.4%) and drug dependence (5.3%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Naloxone was responsible.

How serious are the reports?

94.2% are marked serious by the reporter. Among the outcomes recorded, 35% of reports include death and 49.2% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.

Who files these reports?

other health professional (55.3%), physician (23.3%) and consumer or non-health professional (12%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Naloxone rising?

129 reports in the 12 months to June 2026, down 55% from 285 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.

Do these reports show that Naloxone was responsible for these reactions?

No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.

Is this a list of the side effects of Naloxone?

No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.

How do I report an adverse event?

Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Naloxone as a suspect or interacting product; reports listing it only as a concomitant medication (3,114) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.