What the label lists and what reports show
Donidalorsen side effects
Donidalorsen's FDA label: “Most common adverse reactions (incidence ≥ 5%) are injection site reactions, upper respiratory tract infection, urinary tract infection, and abdominal discomfort.” FAERS holds 302 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is injection site pain (23 reports).
- No generic listed
Check it at the source: the donidalorsen FDA label on DailyMed (effective September 24, 2025, Ionis Pharmaceuticals Inc.); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions (incidence ≥ 5%) are injection site reactions, upper respiratory tract infection, urinary tract infection, and abdominal discomfort.
Table 1: Adverse Reactions with DAWNZERA with Incidence ≥5% and More Common than Placebo in Patients with HAE (OASIS-HAE)
| Reaction | Adverse Reaction n (%) | DAWNZERA n (%) | Placebo (N=22) n (%) |
|---|---|---|---|
| Injection site reactions | 11 (24) | 1 (4) | 1 (5) |
| Upper respiratory tract infection | 4 (9) | 2 (9) | 1 (5) |
| Urinary tract infection | 4 (9) | 2 (9) | 0 |
| Abdominal discomfort | 3 (7) | 0 | 0 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following clinically significant adverse reactions are discussed elsewhere in the labeling: Risk of Hypersensitivity Reactions, Including Anaphylaxis [see Warnings and Precautions (5.1) ] Most common adverse reactions (incidence ≥ 5%) are injection site reactions, upper respiratory tract infection, urinary tract infection, and abdominal discomfort. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Ionis Pharmaceuticals at 1-833-644-6647 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of DAWNZERA reflects the exposure in a total of 171 adult and pediatric patients 12 years and older with hereditary angioedema (HAE) from a placebo-controlled trial (OASIS-HAE) [see Clinical Studies (14) ], and 2 other clinical studies. The average duration of DAWNZERA treatment exposure across the 3 clinical studies was 14 months. …
Source: FDA drug label, Ionis Pharmaceuticals Inc., effective September 24, 2025 (SPL set 3ff501e0-f75f-07da-e063-6294a90a0cb7), via openFDA; the full label on DailyMed
What do FAERS reports show?
302 reports list donidalorsen among the medicines taken, each a report of something that happened, not proof the medicine caused it; 0 are coded as a death and 15 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 21 reactions below, 4 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Donidalorsen: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions