Patient Leaflet Updated 15-May-2026 | Otsuka Pharmaceuticals (UK) Ltd
Dawnzera 80 mg solution for injection in pre-filled pen
Dawnzera 80 mg solution for injection in pre-filled pen
donidalorsen
▼This medicine is subject to additional monitoring. This will allow quick identification of new safety information. You can help by reporting any side effects you may get. See the end of section 4 for how to report side effects.
1. What Dawnzera is and what it is used for
2. What you need to know before you use Dawnzera
3. How to use Dawnzera
4. Possible side effects
5. How to store Dawnzera
6. Contents of the pack and other information
Dawnzera is a type of medicine called an antisense oligonucleotide inhibitor that contains the active substance donidalorsen. It is used in patients 12 years and older with hereditary angioedema (HAE).to prevent angioedema attacks.
HAE is an inherited condition where the blood does not have enough of a protein called 'C1 inhibitor' or where the C1 inhibitor does not work properly. This leads to too much 'plasma kallikrein', which in turn produces higher levels of a substance called bradykinin in your bloodstream. High levels of bradykinin causes blood vessels to widen and leak fluid into the surrounding tissue leading to the swelling attacks seen in HAE. Symptoms may include stomach pains and swelling of the hands and feet, face, eyelids, lips or tongue, voice-box (larynx), which may make breathing difficult, genitals stomach and intestines
The active substance in Dawnzera, donidalorsen, blocks the activity of plasma kallikrein, which helps to reduce the amount of bradykinin in the bloodstream and prevents symptoms of HAE.
If you are allergic to donidalorsen or any of the other ingredients of this medicine (listed in section 6).
Talk to your doctor, pharmacist or nurse before using Dawnzera.
Dawnzera can cause serious allergic reactions (see section 4). If you have a severe allergic reaction to Dawnzera seek emergency medical assistance immediately. Symptoms may include:
Dawnzera is not meant to be used during an acute HAE attack. If you experience a breakthrough HAE attack, you should use your regular rescue medicine to treat it.
Dawnzera is not recommended for use in children under 12 years. It has not been studied in this age group.
Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines.
Dawnzera is not known to affect other medicines or be affected by other medicines.
If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before using this medicine.
There is limited information on the safety of Dawnzera during pregnancy and breast-feeding. As a precautionary measure, it is preferable to avoid the use of donidalorsen during pregnancy.
This medicine may pass into breast milk and it is not known if this medicine can affect your baby. Your doctor will discuss with you whether to stop treatment with this medicine while you are breast-feeding, or to stop breast-feeding.
Your doctor will discuss with you the risks and benefits of using this medicine.
This medicine has no or negligible influence on the ability to drive and use machines.
This medicine contains less than 1 mmol sodium (23 mg) per pre-filled pen, that is to say essentially 'sodium-free'.
Always use use this medicine exactly as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure.
Dawnzera is a solution provided in a single-use pre-filled pen for injection.
The recommended dose is one pre-filled pen once a month. If you have not had an attack for a long period, your doctor may change the dose to one pen every 2 months.
Your treatment will be started and managed under the supervision of a doctor experienced in the care of patients with HAE. You or a caregiver can inject this medicine after appropriate training. A doctor, pharmacist or nurse should show you how to prepare and inject Dawnzera properly before you use it for the first time. Do not inject yourself or someone else until you have been trained to inject the medicine.
If you inject Dawnzera yourself or if your caregiver injects it, you or your caregiver must carefully read and follow the detailed instructions in the "Instructions for use".
Tell your doctor, pharmacist or nurse if you use too much Dawnzera.
Do not use a double dose to make up for a forgotten dose.
Use the missed dose as soon as you remember. Thereafter resume dosing at the prescribed dosing frequency (once monthly or once every 2 months) from the date of the most recently administered dose.
It is important that you keep injecting Dawnzera as instructed by your doctor, even if you feel better.
If you have any further questions on the use of this medicine, ask your doctor, pharmacist or nurse.
Like all medicines, this medicine can cause side effects, although not everybody gets them.
This medicine may cause a severe allergic reaction (with a common frequency: may affect up to 1 in 10 people). If you have a severe allergic reaction, tell your doctor, pharmacist or nurse immediately. Symptoms include:
Tell your doctor, pharmacist or nurse if you notice any of the following side effects.
Very common (may affect more than 1 in 10 people)
If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects you can help provide more information on the safety of this medicine.
Keep this medicine out of the sight and reach of children.
Do not use this medicine after the expiry date which is stated on the label and carton after EXP. The expiry date refers to the last day of that month.
Store in a refrigerator (2 °C - 8 °C). Keep the pre-filled pen in the outer carton in order to protect from light.
The pre-filled pen may be stored at room temperature (up to 30 °C) for a single period of up to 6 weeks, but not beyond the expiry date.
If you store Dawnzera at room temperature, write the discard date on the original carton. The discard date is maximally 6 weeks after you take the medicine out of the refrigerator, and should be noted in the space indicated on the original carton for storage at room temperature up to 30 °C.
Do not use this medicine if you notice the following:
Do not throw away any medicines via household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.
Dawnzera is a clear, colourless to yellow solution for injection in a pre-filled pen.
Dawnzera is available as:
Not all pack sizes may be marketed.
For any information about this medicine, please contact:
This leaflet was last revised in 05/2026
P-4106-01
2 Windsor Dials, Arthur Road, Windsor, SL4 1RS, UK
+44 (0)20 8848 0529
http://www.otsuka-europe.com
