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Pronunciation: Teg-SED-ee
Generic name: inotersen
Dosage form: prefilled injection for subcutaneous use
Drug class: Miscellaneous metabolic agents

Medically reviewed by Carmen Pope, BPharm. Last updated on May 8, 2024.

What is Tegsedi?

Tegsedi (inotersen) is an RNA-targeting treatment that may be used to reduce the symptoms of polyneuropathy (multiple nerve damage) caused by hereditary transthyretin-mediated amyloidosis (hATTR) in adults. Tegsedi can be self-administered by a once-weekly subcutaneous (under the skin) injection.

hATTR is caused by a genetic mutation in the gene that makes a protein called transthyretin (TTR), which is mostly made in the liver. This mutant gene causes proteins to form an unusual shape and clump together in clusters called amyloid fibrils. These build up in the body, damaging tissues, organs, and nerves.

Tegsedi is an antisense oligonucleotide which is a very short piece of synthetic RNA that can attach to and block the genetic material of the cell responsible for producing TTR. This reduces the production of TTR  and TTR protein deposits in tissues.

Because of the risk of serious bleeding kidney problems, Tegsedi is only available through a restricted program called the Tegsedi Risk Evaluation and Mitigation (REMS) Program.

Tegsedi was FDA-approved on October 5, 2018. There is no Tegsedi generic available.

Tegsedi side effects

Tegsedi may cause serious side effects, including low platelet counts, kidney inflammation, inflammatory and immune system reactions, allergic reactions, liver damage, or stroke. See warnings below.

The most common side effects of Tegsedi affecting 20% or more people taking it include:

These are not all the possible side effects of Tegsedi. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.


Tegsedi can cause the following serious side effects.

Low platelet counts (thrombocytopenia) reduce the ability of your body to form clots. You could have serious bleeding that could lead to death. Call your healthcare provider immediately if you have:

Kidney inflammation (glomerulonephritis). Your kidneys may stop working properly resulting in severe kidney damage and kidney failure that needs dialysis. Call your healthcare provider immediately if you have:

Your healthcare provider will do laboratory tests to check your platelet count and kidneys before you start Tegsedi, and while you are using it. Your healthcare provider should also do laboratory tests for 8 weeks after you stop Tegsedi. You must make sure you get these laboratory tests done.

Tegsedi may cause a stroke. One person had a stroke, which occurred within 2 days after the first dose of Tegsedi. Get emergency help immediately if you have symptoms of a stroke, which may include:

Serious inflammatory and immune system problems have been reported in people taking Tegsedi. Talk to your healthcare provider immediately if you have weakness or spasms in your legs, back pain, weight loss, headache, vomiting, or problems with your speech or walking.

Tegsedi may cause liver problems. Your healthcare provider should do laboratory tests to check your liver before you start treatment and while you are using it. Tell your healthcare provider if you develop any liver symptoms such as unexpected nausea and vomiting, stomach pain, not feeling hungry, yellowing of the skin, or having dark urine.

Tegsedi may cause serious allergic reactions. These allergic reactions often occur within 2 hours of injecting Tegsedi. Get emergency help immediately if you have any symptoms of an allergic reaction including joint pain, chest pain, high blood pressure, chills, flushing, difficulty swallowing, redness on palms of hands, tremors or jerking movements, muscle pain, or flu-like symptoms.

Eye problems caused by low vitamin A levels may occur because treatment with Tegsedi will lower the Vitamin A levels in your blood. Your healthcare provider should tell you to take Vitamin A supplements while using Tegsedi and what dose to take. Call your healthcare provider if you have eye problems, such as having difficulty seeing at night or in low-lit areas (night blindness). Your healthcare provider should send you to see an eye doctor (ophthalmologist).

It is not known if Tegsedi is safe and effective in children.

Before taking

You should not receive Tegsedi if you:

Before you start using Tegsedi, tell your healthcare provider about all your medical conditions, including if you:


It is not known if Tegsedi can harm an unborn baby. There is a registry for women who become pregnant during treatment with Tegsedi if you become pregnant while taking Tegsedi; talk to your healthcare provider about registering with the TEGSEDI Pregnancy Exposure Registry.

The purpose of this registry is to collect information about your health and your baby’s health. You can get more information about this registry by calling: 1-877-465-7510, emailing:, or visiting online at:


It is not known if Tegsedi can pass into your breast milk or harm your baby. Talk with your healthcare provider about the best way to feed your baby while you are using it.

How should I use Tegsedi?

Your healthcare provider will show you or your caregiver how to inject Tegsedi the first time. Do not attempt to use it until you have been shown how to do so. Also, read the detailed medication guide.

Tegsedi is usually injected once a week. It should be injected on the same day each week (for example, every Monday)

Tegsedi dosage

The recommended dosage of Tegsedi is 284 mg (one prefilled injection) administered by subcutaneous injection once weekly.

What happens if I miss a dose

If you miss a dose, take the missed Tegsedi dose as soon as possible, unless your next scheduled dose is within 2 days. If your next scheduled dose is within 2 days, skip the missed dose and take your next scheduled dose on the scheduled day.

What other drugs will affect Tegsedi?

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Especially tell your healthcare provider if you take:

Ask your healthcare provider or pharmacist if you are not sure if you take any of these medicines. Know the medicines you take. Keep a list of them to show your healthcare provider or pharmacist when you get a new medicine.


Store Tegsedi in the refrigerator between 36°F to 46°F (2°C to 8°C) in the original container. Do not freeze.

Tegsedi prefilled syringes can also be kept at room temperature less than 86°F (30°C) in the original container for up to 6 weeks. Do not exceed these temperatures. If you do not use Tegsedi that has been kept at room temperature within 6 weeks, throw it away.

Protect from light.

Keep out of the reach of children.

Tegsedi ingredients

Active ingredients: inotersen 284 mg/ 1.5 mL

Inactive ingredients: purified water (water for injection), hydrochloric acid, and or sodium hydroxide for pH adjustment.

Available as a single-dose prefilled syringe.


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Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.