Pharmacologic class (EPC) · 3 drug pages

Antisense oligonucleotide: adverse event reports filed with FDA

10,452 reports list a drug in this class as a suspect or interacting product, 2017–2026.

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.

10,452
reports across the class: 0.1% of all reports; 1,223
reports, 12 months to June 2026: 1,061 in the 12 months before; 39.7%
marked serious by the reporter: 57.4% across all reports; 3
drugs with a page: brand and generic names counted separately

Antisense oligonucleotide is a pharmacologic class (an FDA Established Pharmacologic Class) with 3 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 10,452 adverse event reports received by FDA, 0.1% of the database, from January 2017 to June 2026.

1,223 reports arrived in the 12 months to June 2026, up 15% from 1,061 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 39.7% of the class's reports are marked serious, 7.9% record death among the outcomes and 25.3% record hospitalisation, as reported.

Across the class the reactions recorded most often are product dose omission issue (9%), no adverse event (6.9%) and headache (5.4%). 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
SpinrazaNusinersen	brand	7,451	591	49%	Headache
Exondys 51Eteplirsen	brand	2,237	458	17.1%	Product dose omission issue
Amondys 45Casimersen	brand	764	174	15.3%	Product dose omission issue

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

Product dose omission issuea dose was missed9%941
No adverse eventno adverse event was reported6.9%718
Headachehead pain5.4%560
Post lumbar puncture syndrome4.9%514
Pyrexiafever4.7%490
Pneumonialung infection4.1%426
Procedural painpain from a procedure3.6%379
Intentional dose omission3.4%353
Deaththe patient died; cause not stated by this term3.2%339
Vomitingbeing sick3.1%320
Astheniaweakness or lack of energy2.8%290
Poor venous access2.7%286
Malaisegeneral feeling of being unwell2.7%281
Device issuea problem with the device2.5%259
Back painback pain2.4%255
Falla fall2.2%230
Scoliosis2.2%228
Fatiguetiredness2.2%226
Covid-19COVID-19 infection2.1%223
Influenzaflu2%210
Nasopharyngitisa cold1.9%195
Nauseafeeling sick1.8%184
Painpain, site not specified1.7%173
Coughcough1.5%162
Drug ineffectivethe medicine did not work as expected1.3%140

Solid bar: share of all class reports. Hollow bar: the median share across the 3 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death7.9%824

Life-threatening1%102

Hospitalisation (initial or prolonged)25.3%2,646

Disability0.3%28

Congenital anomaly0%3

Other serious11.9%1,246

Not serious60.3%6,302

Patient age

Under 26%630

2 to 1120.4%2,134

12 to 1713.6%1,420

18 to 4419%1,987

45 to 643.9%410

65 to 740.6%63

75 and over0.1%13

Age not given36.3%3,795

Who reported

Physician19.7%2,064

Pharmacist1.9%200

Other health professional29.4%3,073

Lawyer0%0

Consumer or non-health professional48.8%5,103

Not given0.1%12

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 Antisense oligonucleotide reports

Which drugs are in the Antisense oligonucleotide class on this site?

Spinraza, Exondys 51 and Amondys 45. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

10,452 reports through June 2026, 1,223 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?

product dose omission issue (9%), no adverse event (6.9%), headache (5.4%), post lumbar puncture syndrome (4.9%) and pyrexia (4.7%).

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.