Alprolix (eftrenonacog alfa) is a factor IX replacement medicine used to treat and help prevent bleeding in people with hemophilia B.
Like most medicines, Alprolix can cause side effects. Some are more common than others, while some are rare but serious.
Keep reading to learn about the possible side effects of Alprolix, what you can do to manage them, and when to contact your health care provider.
This article doesn't include every possible side effect. Tell your health care provider about any symptoms that concern you or don't improve, even if they aren't listed here.
Common Side Effects of Alprolix
The most commonly reported side effects of Alprolix include:
- Headache
- Tingling or numbness in the mouth (oral paresthesia)
- Redness or discoloration at the infusion site
Serious Side Effects of Alprolix
Less commonly, Alprolix has been linked to more serious effects, including:
- Allergic reactions, including anaphylaxis
- Development of factor IX inhibitors (antibodies that can stop the medicine from working)
- Blood clots
- Blood in the urine and clot formation in the urinary tract
If you have any symptoms that feel serious or life-threatening, seek medical care right away.
How to Manage Alprolix Side Effects
While not a complete guide, the following tips can help you manage some of the more common or important side effects of Alprolix.
1. Headache
Headache is a commonly reported side effect of Alprolix. Symptoms may include mild-to-moderate head pain or pressure.
To help manage headaches:
- Rest in a quiet, dark room if needed.
- Drink enough fluids throughout the day.
- Try relaxation techniques, such as deep breathing.
- Maintain a regular sleep schedule.
- Eat regular meals or snacks.
An over-the-counter (OTC) pain reliever may help ease headache, but check with your health care provider or pharmacist first to make sure it's safe for you.
2. Irritation at the infusion site
Some people notice redness where the infusion is given. Other possible symptoms near the site include mild swelling or discomfort.
These symptoms are usually mild and temporary. Tips that may help:
- Choose a different spot for infusion each time, rather than always using the same one.
- Review the step-by-step reconstitution and infusion instructions that come with Alprolix, or ask your health care provider to walk through your technique with you.
- Ask your health care provider whether it is OK to use a cool compress on the area.
Let your health care provider know if site reactions persist or feel severe.
3. Allergic reactions
Allergic reactions, including a severe reaction called anaphylaxis, have happened with Alprolix. The risk may be higher in people who go on to develop a factor IX inhibitor, so a new allergic-type reaction can sometimes be an early sign that an inhibitor has formed.
Possible symptoms include:
- Hives, rash, or swelling of the face
- Chest tightness, wheezing, or trouble breathing
- A drop in blood pressure, which can cause dizziness or fainting
- Nausea, vomiting, or a tingling or restless feeling
If you have any of these symptoms during or after an infusion, stop the infusion and call your health care provider. Seek emergency care right away if symptoms are severe or getting worse. Your health care provider may want to test you for a factor IX inhibitor if you have an allergic reaction.
4. Factor IX inhibitors
An inhibitor is an antibody your body can make against factor IX. If you develop one, Alprolix (and other factor IX products) may not raise your factor IX level or control bleeding as well as expected.
Signs to watch for include bleeding that doesn't respond to your usual dose or happens more often even if you follow your regular schedule.
Your health care provider will regularly test your blood for inhibitors. They may also order a test if your bleeding does not respond as expected. If an inhibitor is found, your health care provider will discuss next steps with you, which may include a different type of treatment.
Alprolix itself is not approved for immune tolerance induction, a treatment used to lower inhibitor levels. This treatment has been linked to a kidney condition called nephrotic syndrome in some people using other factor IX products.
Never adjust your dose or switch products on your own if you think an inhibitor might be affecting your treatment. Talk to your health care provider first.
5. Blood clots
Factor IX products, including Alprolix, have been linked to blood clots (thromboembolic events). This risk may be higher if Alprolix is given as a continuous infusion through a central line instead of as a bolus (a single, direct dose given over several minutes), which is the only way Alprolix has been studied and is meant to be given.
Possible symptoms of a blood clot include:
- Chest pain or trouble breathing
- Swelling in an arm or leg, with or without pain or tenderness
- Sudden weakness, numbness, or trouble speaking
Seek emergency care right away if you have any of these symptoms.
6. Blood in the urine
Some people using Alprolix have reported blood in the urine (hematuria). In some cases, a blood clot can block the urinary tract.
Symptoms may include pink, red, or brown-colored urine, pain in your side or lower back, or trouble urinating.
Tell your health care provider right away if you notice blood in your urine or new pain in your side. This may be managed with fluids and monitoring.
Contact your health care provider about any side effect, even if it isn't listed here.
Reducing Your Risk of Alprolix Side Effects
You can help lower your risk of side effects by using Alprolix exactly as prescribed and following your health care provider's instructions closely.
Helpful tips include:
- Tell your pharmacist and other health care providers about everything you take, including prescription medicines, OTC products, and any vitamins, herbs, or supplements.
- Ask before starting or stopping anything, including Alprolix itself.
- Keep all recommended lab test appointments, including inhibitor testing.
- Report any new or worsening symptoms to your health care provider right away.
Do not stop using Alprolix or change your treatment plan on your own. Your health care provider can review your regimen and make adjustments if needed to help make sure Alprolix continues to be safe and effective for you.