Pharmacologic class (EPC) · 10 drug pages

Opioid antagonist: adverse event reports filed with FDA

31,239 reports list a drug in this class as a suspect or interacting product, 2004–2026.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event." The information in these reports "cannot be used to estimate the incidence of these events."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

31,239
reports across the class: 0.2% of all reports; 1,053
reports, 12 months to June 2026: 1,179 in the 12 months before; 62.4%
marked serious by the reporter: 57.4% across all reports; 10
drugs with a page: brand and generic names counted separately

Opioid antagonist is a pharmacologic class (an FDA Established Pharmacologic Class) with 10 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 31,239 adverse event reports received by FDA, 0.2% of the database, from February 2004 to June 2026.

1,053 reports arrived in the 12 months to June 2026, down 11% from 1,179 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 62.4% of the class's reports are marked serious, 8.7% record death among the outcomes and 20.4% record hospitalisation, as reported.

Across the class the reactions recorded most often are drug dependence (15.2%), drug withdrawal syndrome (13.3%) and pain (10%). The class median share shown beside each term is the middle value across the member drugs; it is the comparison used on every drug page in this class.

The members table is 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."

Drugs in the class

Drug	Name type	Reports	Latest 12 months	Marked serious	Top term recorded
SuboxoneBuprenorphine hydrochloride, naloxone hydrochloride	brand	20,919	552	66.8%	Drug dependence
MovantikNaloxegol oxalate	brand	1,997	45	26.9%	Diarrhoea
Buprenorphine and naloxone	generic	1,935	66	53.7%	Nausea
Naloxone	generic	1,693	129	94.2%	Toxicity to various agents
RelistorMethylnaltrexone bromide	brand	978	28	55.4%	Death
ZubsolvBuprenorphine hydrochloride and naloxone hydrochloride	brand	973	44	21%	Nausea
NarcanNaloxone hydrochloride	brand	835	38	56.2%	Toxicity to various agents
Buprenorphine hydrochloride, naloxone hydrochloride	generic	824	77	57.9%	Pain
SymproicNaldemedine	brand	548	13	47.3%	Diarrhoea
Naloxone hydrochloride	generic	537	61	73.4%	Drug ineffective

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."

Reports by month, five years

FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

Reactions recorded across the class

share of class reports recording the termmedian drug in the class

Drug dependencedependence on a medicine15.2%4,749
Drug withdrawal syndromesymptoms on stopping a medicine13.3%4,159
Painpain, site not specified10%3,132
Off label useused for a purpose or in a way not on the label7.7%2,393
Overdosea dose above the recommended amount7.3%2,278
Nauseafeeling sick6.6%2,076
Emotional distressemotional distress5.9%1,836
Anxietyanxiety5.6%1,751
Vomitingbeing sick5.6%1,740
Drug ineffectivethe medicine did not work as expected5%1,556
Drug abusemisuse of a medicine4.3%1,347
Foetal exposure during pregnancythe unborn baby was exposed to the medicine4.3%1,340
Headachehead pain4.1%1,268
Maternal exposure during pregnancythe mother took the medicine during pregnancy3.8%1,176
Toxicity to various agentspoisoning or toxic effect of one or more substances3.7%1,143
Substance abuse3.6%1,137
Insomniadifficulty sleeping3.5%1,101
Feeling abnormalfeeling odd or not right3.5%1,093
Product use issuea problem in how the product was used3.5%1,091
Drug withdrawal syndrome neonatal3.5%1,085
Diarrhoealoose or frequent stools3.4%1,074
Intentional underdose3.4%1,061
Depressionlow mood3.1%973
Hyperhidrosisexcessive sweating3.1%970
Wrong technique in product usage processthe product was used in the wrong way3.1%955

Solid bar: share of all class reports. Hollow bar: the median share across the 10 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death8.7%2,722

Life-threatening3.5%1,088

Hospitalisation (initial or prolonged)20.4%6,382

Disability4.2%1,301

Congenital anomaly0.5%163

Other serious45.7%14,280

Not serious37.6%11,747

Patient age

Under 21.1%338

2 to 110.5%142

12 to 170.4%117

18 to 4424.7%7,727

45 to 6414.1%4,402

65 to 743%932

75 and over1.6%510

Age not given54.6%17,071

Who reported

Physician19.5%6,098

Pharmacist3.7%1,169

Other health professional14.1%4,415

Lawyer9.1%2,848

Consumer or non-health professional48.6%15,185

Not given4.9%1,524

Grey bar: all 20,646,523 reports in the database. Outcome flags are as the reporter set them and are not verified by FDA.

Questions about Opioid antagonist reports

Which drugs are in the Opioid antagonist class on this site?

Suboxone, Movantik, Buprenorphine and naloxone, Naloxone, Relistor and Zubsolv and 4 more. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

31,239 reports through June 2026, 1,053 of them in the latest 12 months. A report listing two drugs of the class counts once for each.

What reactions are recorded most often?

drug dependence (15.2%), drug withdrawal syndrome (13.3%), pain (10%), off label use (7.7%) and overdose (7.3%).

Can the members table be used to rank the drugs?

No. 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." Drugs differ in how many people take them, in the conditions they treat, in time on the market and in how diligently reports are collected.

How do I report an adverse event?

Through FDA MedWatch (Form FDA 3500, or 1-800-FDA-1088) or to the manufacturer. 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 class is the Established Pharmacologic Class most often attached to a drug's reports by openFDA's label harmonisation, or from the NDC Directory where reports carry none. 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.