As with other drugs, Onpattro (patisiran) can cause side effects, such as infusion-related reactions and breathing issues. If you are not able to tolerate side effects of Onpattro, talk with your doctor or pharmacist.

Onpattro (patisiran) is a brand-name intravenous (IV) infusion used for nerve damage in adults with hereditary amyloid transthyretin-mediated (hATTR) amyloidosis.

If you have problems with side effects from Onpattro infusion, talk with your doctor or pharmacist. They can discuss ways to manage side effects or other available treatment options.

For additional information about Onpattro, including details about its uses, see this Onpattro overview article.

Onpattro can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects persist, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who received Onpattro in clinical trials:

For more information about difficulty breathing and infusion-related reaction, see the “Side effect specifics” section.

Mild side effects can occur with Onpattro use. This list does not include all possible mild side effects of the drug. For more information, you can refer to the drug’s prescribing information.

Mild side effects that have been reported with Onpattro include:

  • upset stomach
  • joint pain
  • skin redness or other color changes
  • dry eyes
  • blurred vision
  • bronchitis
  • muscle spasms
  • vertigo (spinning sensation)
  • upper respiratory infection
  • difficulty breathing (see the “Side effect specifics” section)

These side effects may be temporary, lasting a few days to weeks. However, if the side effects continue, worsen, or become too difficult to tolerate, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking Onpattro and want to tell the FDA about it, visit MedWatch.

Onpattro may cause serious side effects. The following list may not include all possible serious side effects of the drug. For more information, you can refer to the prescribing information for Onpattro.

If you develop serious side effects while taking Onpattro, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

  • atrioventricular heart block, which may include symptoms such as:
    • lightheadedness
    • dizziness
  • extravasation (when the drug seeps into veins and tissues surrounding the IV site), which may include symptoms such as:
    • burning sensation
    • skin redness or other color changes
    • phlebitis
  • low vitamin A level, which in severe cases of vitamin A deficiency may include symptoms such as:
  • infusion-related reaction (see the “Side effect specifics” section)
Allergic reaction

For some people, Onpattro can cause an allergic reaction, but this side effect wasn’t reported in the drug’s studies.

In general, symptoms of an allergic reaction can be mild or serious.

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to Onpattro infusions, your doctor may recommend taking a different medication instead.

Learn more about some of the side effects that Onpattro may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Onpattro.

Infusion-related reaction

Infusion reactions were one of the most common side effects reported in Onpattro clinical trials. An infusion reaction is an immune response to receiving a medication by infusion into a vein. (Onpattro is given as an IV infusion by a healthcare professional.)

Infusion reactions can be mild to serious, even life threatening. Symptoms can include:

What you can do

To help lower your risk of this side effect, your care team will give you medications before each Onpattro infusion. They’ll also monitor you for signs and symptoms of a reaction during your infusion.

If you develop symptoms during the infusion, your doctor will likely slow it down or may stop it temporarily. They may also need to give you more medications to help ease the reaction.

After your infusion appointment, call your doctor right away if you experience any of the symptoms above. If they seem life threatening or you think you’re having a medical emergency call 911 or your local emergency number right away.

For information about Onpattro infusion schedules, see this overview of Onpattro and dosage.

Difficulty breathing

Treatment with Onpattro may cause difficulty breathing, apart from breathing problems related to an infusion reaction (see above). Difficulty breathing, including shortness of breath with exercise, was a common side effect in Onpattro studies.

Other possible symptoms along with difficulty breathing can include:

What you can do

If you experience this side effect during Onpattro treatment, talk with your doctor. They can check your symptoms and prescribe breathing treatments or other medications to help ease your symptoms.

You may need to adjust your physical activity level if you have difficulty breathing. For example, if you get short of breath when you exercise, you may need to exercise at a lower intensity or take more frequent breaks.

If you have questions about this side effect or how to modify your physical activity, talk with your doctor for more information.

Before starting Onpattro, discuss your health history with your doctor. Onpattro may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

  • previous allergic reaction to this or a similar drug
  • pregnancy
  • breastfeeding

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.