Pharmacologic class (EPC) · 8 drug pages

Partial opioid agonist: adverse event reports filed with FDA

94,902 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.

94,902
reports across the class: 0.5% of all reports; 4,116
reports, 12 months to June 2026: 4,590 in the 12 months before; 60.2%
marked serious by the reporter: 57.4% across all reports; 8
drugs with a page: brand and generic names counted separately

Partial opioid agonist is a pharmacologic class (an FDA Established Pharmacologic Class) with 8 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 94,902 adverse event reports received by FDA, 0.5% of the database, from January 2004 to June 2026.

4,116 reports arrived in the 12 months to June 2026, down 10% from 4,590 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 60.2% of the class's reports are marked serious, 28.6% record death among the outcomes and 9.9% record hospitalisation, as reported.

Across the class the reactions recorded most often are drug dependence (14.9%), death (14.4%) and overdose (14.1%). 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
ButransBuprenorphine	brand	60,029	590	57.3%	Death
Buprenorphine	generic	19,240	1,749	79.3%	Drug dependence
SublocadeBuprenorphine	brand	5,028	434	20.3%	Drug withdrawal syndrome
Buprenorphine hydrochloride	generic	4,069	210	94.1%	Dependence
BelbucaBuprenorphine hydrochloride	brand	3,039	284	60.4%	Dependence
BrixadiBuprenorphine	brand	1,973	680	7.3%	Withdrawal syndrome
Buprenorphine Transdermal SystemBuprenorphine	brand	955	169	11.7%	Product adhesion issue
Buprenorphine hcl	generic	569	0	92.1%	Intentional drug misuse

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 medicine14.9%14,185
Deaththe patient died; cause not stated by this term14.4%13,696
Overdosea dose above the recommended amount14.1%13,401
Toxicity to various agentspoisoning or toxic effect of one or more substances11.5%10,933
Painpain, site not specified8.9%8,407
Drug withdrawal syndromesymptoms on stopping a medicine7.8%7,363
Drug ineffectivethe medicine did not work as expected6.7%6,386
Emotional distressemotional distress6.1%5,777
Nauseafeeling sick4.6%4,331
Dependence4.3%4,069
Drug abusemisuse of a medicine4.2%3,991
Product adhesion issue3.9%3,745
Application site rash3.2%3,077
Inadequate analgesia3.2%3,051
Dizzinesslight-headedness or unsteadiness2.8%2,704
Rashskin rash2.7%2,559
Application site pruritusitching where the product was applied2.5%2,404
Vomitingbeing sick2.5%2,404
Headachehead pain2.4%2,282
Drug withdrawal syndrome neonatal2.3%2,176
Maternal exposure during pregnancythe mother took the medicine during pregnancy2.3%2,137
Off label useused for a purpose or in a way not on the label2.2%2,131
Depressionlow mood2.2%2,064
Anxietyanxiety2%1,885
Application site erythemaredness where the product was applied1.9%1,786

Solid bar: share of all class reports. Hollow bar: the median share across the 8 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death28.6%27,169

Life-threatening2.7%2,522

Hospitalisation (initial or prolonged)9.9%9,408

Disability4.6%4,347

Congenital anomaly3%2,807

Other serious34.5%32,784

Not serious39.8%37,753

Patient age

Under 20.3%253

2 to 110.1%105

12 to 170.2%149

18 to 4410%9,488

45 to 646.3%5,976

65 to 741.7%1,614

75 and over1.9%1,779

Age not given79.6%75,538

Who reported

Physician8.9%8,454

Pharmacist3.2%3,070

Other health professional11.4%10,793

Lawyer29%27,550

Consumer or non-health professional46.8%44,423

Not given0.6%612

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 Partial opioid agonist reports

Which drugs are in the Partial opioid agonist class on this site?

Butrans, Buprenorphine, Sublocade, Buprenorphine hydrochloride, Belbuca and Brixadi and 2 more. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

94,902 reports through June 2026, 4,116 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 (14.9%), death (14.4%), overdose (14.1%), toxicity to various agents (11.5%) and pain (8.9%).

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.