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Pronunciation: pah-tis-er-ran
Generic name: patisiran
Brand name: Onpattro
Dosage form: solution for intravenous infusion
Drug class: Miscellaneous metabolic agents

Medically reviewed by Carmen Pope, BPharm. Last updated on May 24, 2024.

What is patisiran (Onpattro)?

Patisiran (Onpattro) is an injectable transthyretin-directed small interfering RNA given by infusion that may be used to treat polyneuropathy (multiple nerve damage) caused by hereditary transthyretin-mediated amyloidosis (hATTR) in adults. hATTR occurs when your liver produces faulty transthyretin (TTR) proteins and TTR deposits accumulate in organs and tissues, most commonly the peripheral nerves.

Patisiran mechanism of action is to break down mutant and wild-type transthyretin (TTR) proteins through RNA interference. TTR is an important protein primarily produced by the liver, that carries the thyroid hormone thyroxine and retinol (vitamin A) throughout the body. Patisiran decreases serum levels of TTR protein and protein deposits in tissues, relieving the symptoms of polyneuropathy.

Patisiran was FDA-approved on August 10, 2018, under the brand name Onpattro. There is no Onpattro generic.

Patisiran side effects

Patisiran can cause serious side effects, such as allergic reactions, infusion-related reactions, and vision problems. See warnings below.

The most common side effects of patisiran occurring in at least 10% of people administered it include upper respiratory tract infections (with symptoms such as stuffy nose, sneezing, and sore throat) and infusion-related reactions.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to Alnylam Pharmaceuticals at 1-877-256-9526 or FDA at 1-800-FDA-1088 or


Get emergency medical help if you have signs of an allergic reaction to patisiran with symptoms such as hives; difficulty breathing; and swelling of your face, lips, tongue, or throat.

A reaction may occur while you are being administered patisiran, in some people this could be serious or life-threatening. Tell your medical caregiver if you feel warm, dizzy, nauseated, light-headed, itchy, sweaty, or have a headache, chest tightness, back pain, trouble breathing, or swelling in your face.

Patisiran reduces serum vitamin A levels. Your healthcare provider will talk to you about taking the recommended daily allowance of vitamin A. Do not take higher than recommended doses of vitamin A to try to achieve normal serum vitamin A levels during treatment, as serum vitamin A levels do not reflect the total vitamin A in the body. Talk to your healthcare provider who should refer you to an ophthalmologist if you develop eye symptoms suggestive of vitamin A deficiency, such as night blindness.

Before receiving patisiran

Before receiving patisiran tell your doctor about all your medical conditions or allergies. Especially tell your doctor if you are:


Patisiran may harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant. If you are pregnant, your name may be listed on a pregnancy registry to track the effects of patisiran on the baby.


It may not be safe to breastfeed while using this medicine. Ask your doctor about any risks.

How is patisiran administered?

Patisiran infusion is given by a healthcare provider into a vein (intravenously) over about 80 minutes.

The recommended dosage of patisiran is based on your weight.

You may be given other medications, such as corticosteroids, acetaminophen, and antihistamines to help prevent serious side effects or an infusion reaction.

Tell your caregivers if you feel any burning, pain, or swelling around the IV needle when patisiran is injected.

Your doctor may have you take vitamin A while you are using patisiran. Take only the amount of vitamin A your doctor has prescribed, especially if you are pregnant. Vitamin A deficiency or excess in expectant mothers can cause vision problems or CNS deformities and other serious side effects in the unborn baby.

Call your doctor at once if you have vision problems (especially at night) while you are taking patisiran.

You may need frequent medical tests. Even if you have no symptoms, tests can help your doctor determine if this medicine is effective. You may also need frequent eye exams.

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for your patisiran.

What happens if I overdose?

Since patisiran is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid while using patisiran?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect patisiran?

Other drugs interact with patisiran, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

No formal clinical drug interaction studies have been performed but patisiran is not expected to cause drug-drug interactions or to be affected by inhibitors or inducers of cytochrome P450 enzymes.

See the patisiran package insert for more information about drug interactions.


Store in the refrigerator at 2°C to 8°C (36°F to 46°F). Do not freeze. Discard the vial if it has been frozen.

If refrigeration is unavailable, patisiran can be stored at room temperature up to 25°C (up to 77°F) for up to 14 days.

Once diluted, the solution should be administered immediately after preparation. If not used immediately, store in the infusion bag at room temperature (up to 30°C [86°F]) for up to 16 hours (including infusion time). Do not freeze.

Onpattro ingredients

Active: patisiran sodium

Inactive: MC-3, 1,2-dimyristoyl-SN-glycero-3-carboxaminopropylpolyethylene glycol 2000 methyl ether, 1,2-distearoyl-sn-glycero-3-phosphocholine, cholesterol, sodium phosphate, dibasic, heptahydrate, monobasic potassium phosphate, sodium chloride, water.

Available as a lipid complex injection: 10 mg/5 mL (2 mg/mL) in a single-dose vial for intravenous infusion.


Alnylam Pharmaceuticals, Inc.

Popular FAQ

Onpattro (patisiran) is the first FDA approval of a new class of drugs called small interfering ribonucleic acid (siRNA) treatments. Onpattro is used for the treatment of the polyneuropathy of hereditary transthyretin-mediated amyloidosis in adults. Onpattro works by encasing siRNA in lipids and stops the production of disease-causing amyloid proteins. Continue reading

More FAQ

Further information

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