Nusinersen Injection
Nusinersen Injection (Spinraza) is a spinal injection used to treat spinal muscular atrophy (SMA) in children and adults.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
Nusinersen (Spinraza) is a specialist medicine for spinal muscular atrophy (SMA) in children and adults. It helps a backup gene, SMN2, make more of the working SMN protein that people with SMA lack, and on the U.S. market since about 2016, it was the first approved SMA treatment. It is generally well tolerated, with many complaints coming from the spinal tap itself (headache, back pain, vomiting), and infants may also get chest infections, constipation or fever. Watch for unusual bleeding or bruising, since it can lower platelets and disturb clotting; that is why blood tests and a urine kidney check come before every dose.
Clinical pearls
- Maintenance doses are spaced months apart, so book the next spinal injection before leaving each visit to avoid gaps.
- Tell any surgeon or dentist you receive Spinraza before a procedure, since it can affect platelets and clotting.
- Report fever, stiff neck or a lasting headache after an injection promptly, since spinal infections like meningitis can follow.
- In infants, the care team tracks height over time, because Spinraza may slow growth.
Patient information guide A plain-language walkthrough of Nusinersen Injection, written from its FDA label.
What Nusinersen Injection is used for
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Nusinersen Injection is used for one condition.
- Spinraza (intrathecal injection) treats spinal muscular atrophy (SMA) in pediatric and adult patients.
How Nusinersen Injection works
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SMA happens when mutations in chromosome 5q cause a shortage of SMN protein. Nusinersen is an antisense oligonucleotide, a short strand of genetic material. It acts on the SMN2 gene's messenger RNA so that more full-length, working SMN protein is made. This was shown in lab assays and animal models.
Nusinersen Injection dosage
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Spinraza is injected into the spinal fluid by trained healthcare professionals. It is not taken with food or by mouth. Treatment has a loading phase of closely spaced doses, then maintenance doses about every 4 months. There are two regimen options, and your prescriber picks one.
- Sedation or ultrasound guidance may be considered, especially in younger patients.
- If a dose is missed, it should be given as soon as possible. The schedule is then adjusted based on how long it has been, so contact your care team.
Dosing details from the FDA-approved label
From the Nusinersen Injection prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Low Dose Regimen
- Four loading doses: one 12 mg dose every 14 days for three doses, then a fourth 12 mg dose 30 days after the third dose
- Then 12 mg maintenance dose once every 4 months starting 4 months after the last loading dose
- Administered intrathecally
- High Dose Regimen
- Two loading doses: one 50 mg dose followed by a second 50 mg dose 14 days later
- Then 28 mg maintenance dose once every 4 months starting 4 months after the last loading dose
- Administered intrathecally
- Transition from Low Dose Regimen to High Dose Regimen
- Administer a single 50 mg bolus dose at least four months (+/- 14 days) after the last 12 mg maintenance dose, followed by a 28 mg maintenance dose once every 4 months thereafter
- Additional clinical benefit not established in a controlled study
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION SPINRAZA is administered intrathecally ( 2.1 ) Recommended Dosage ( 2.1 ) The recommended dosage is one of two options: Low Dose Regimen: Administer one 12 mg loading dose every 14 days for three doses; then a fourth 12 mg loading dose 30 days after the third dose; then administer a 12 mg maintenance dose once every 4 months thereafter. High Dose Regimen: Administer one 50 mg loading dose followed by a second 50 mg loading dose 14 days later; then administer a 28 mg maintenance dose once every 4 months thereafter. Important Preparation and Administration Instructions ( 2.3 ) Allow to warm to room temperature prior to administration Administer within 4 hours of removal from vial Prior to administration, remove 5 mL of cerebrospinal fluid Administer as intrathecal bolus injection over 1 to 3 minutes Laboratory Testing and Monitoring to Assess Safety ( 2.4 ) At baseline and prior to each dose, obtain a platelet count, coagulation laboratory testing, and quantitative spot urine protein testing 2.1 Recommended Dosage SPINRAZA is administered intrathecally by, or under the direction of, healthcare professionals experienced in performing lumbar punctures. Two dosing regimen options for SPINRAZA, which consist of loading followed by maintenance dosages, are presented in Table 1 . Table 1: Recommended Dosage for SPINRAZA Loading Dosages Maintenance Dosage Low Dose Regimen (Low dose with four loading doses) Administer a total of four loading doses as follows: one 12 mg dose every 14 days for three doses, then a fourth 12 mg dose 30 days after the third dose. Administer 12 mg once every 4 months starting 4 months after the last loading dose. High Dose Regimen (High dose with two loading doses) Administer a total of two loading doses as follows: one 50 mg dose followed by a second 50 mg dose 14 days later. Administer 28 mg once every 4 months starting 4 months after the last loading dose. 2.2 Missed Doses Missed Dose of Low Dose Regimen Missed Loading Dose If a 12 mg loading dose (any of the 4 loading doses) is missed, administer the missed loading dose as soon as possible; adjust the date for the subsequent doses to maintain the recommended interval between doses.
Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →
Nusinersen Injection side effects
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Side effects differ by age and regimen. Common ones include:
Common side effects
- Lower respiratory infection (in infantile-onset SMA)
- Constipation (in infantile-onset SMA)
- Fever
- Headache
- Vomiting
- Back pain
- Pneumonia and COVID-19 (in infants on the high dose regimen)
- Pneumonia, COVID-19, aspiration pneumonia and malnutrition (infants on the high dose regimen)
When to get medical help
- Call your doctor about unusual bleeding or bruising. Spinraza can lower platelets (cells that help blood clot) and cause clotting problems.
- Report signs of kidney problems. Kidney toxicity, including a serious kidney inflammation called glomerulonephritis, has been seen with this type of drug.
- Get urgent help for signs of infection after the spinal injection, such as meningitis (infection of the membranes around the brain and spinal cord).
- Seek help for allergic reactions such as swelling of the face or lips (angioedema), hives, or rash.
- Report any new or worsening symptoms after treatment, such as a headache that persists after the lumbar puncture.
Nusinersen Injection warnings and precautions
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- Low platelets and clotting problems can raise bleeding risk. Tests are done before each dose.
- Kidney toxicity, including potentially fatal glomerulonephritis, has been seen with some drugs of this type. Urine protein is tested before each dose.
- Lumbar puncture risks include meningitis, hydrocephalus, aseptic meningitis and arachnoiditis.
- Rash and allergic reactions have been reported.
- Growth in height may be reduced in infants.
Before taking Nusinersen Injection
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- There are no contraindications listed.
- Tell your doctor about bleeding disorders, low platelets or kidney problems.
- Pregnancy: no adequate human data, and animal studies showed neurobehavioral effects in offspring.
- Breastfeeding: no human data, so discuss benefits and risks with your doctor.
- Older adults: not enough people 65 and over were studied.
- The injection should not be given through skin that is infected or inflamed.
What Nusinersen Injection does in the body
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In autopsy samples from three patients, spinal cord tissue had higher levels of SMN2 messenger RNA containing exon 7 than untreated SMA infants. In studies, a small number of treated patients (2.4%) had notable heart-rhythm (QTcF) changes. There was no increase in cardiac adverse reactions linked to delayed ventricular repolarization compared with sham-control.
How your body processes Nusinersen Injection
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Injected into the spinal fluid, nusinersen spreads to central nervous system tissues. Blood levels stay relatively low compared with spinal fluid levels. It is broken down by enzymes called exonucleases and does not interact with CYP450 liver enzymes. Its half-life is very long, about 135 to 177 days in spinal fluid and 63 to 87 days in plasma. It is likely cleared mainly through urine.
How to store Nusinersen Injection
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Store in a refrigerator between 2°C to 8°C (36°F to 46°F) in the original carton to protect from light. Do not freeze. refrigeration is available, SPINRAZA may be stored in its original carton, protected from light at or below 30 o C (86 o F) for up to 14 days.
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Supplements & herbs that interact with Nusinersen Injection
208 supplements and herbal products have documented interactions with Nusinersen Injection in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 4
- Moderate · 186
- Minor · 18
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Nusinersen Injection: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Nusinersen Injection — the kind of thing our pharmacy team would talk through with you at the counter.
What is Spinraza for?
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How is Spinraza given?
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Why do I need blood and urine tests?
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What side effects should I expect?
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Can I use Spinraza if I'm pregnant or breastfeeding?
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What if I miss a dose?
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Is Nusinersen Injection available over the counter?
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When was Nusinersen Injection first available?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Nusinersen Injection on HelloPharmacist
Nusinersen Injection forms and strengths (how it comes)
Nusinersen Injection is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Nusinersen Injection inactive ingredients by manufacturer.
Injection
How this form is used
- Spinraza is used to treat spinal muscular atrophy (SMA) in pediatric and adult patients.
- Spinraza is given into the spinal fluid (intrathecal) by, or under the direction of, professionals experienced in lumbar punctures.
- Spinraza is for intrathecal use only and each vial is single-dose.
- Spinraza is given as a bolus injection over 1 to 3 minutes, after some spinal fluid is removed.
- Spinraza requires platelet, clotting, and urine protein tests before each dose.
Nusinersen Injection on the U.S. market: products, makers and brands
How Nusinersen Injection appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
1 company lists 3 Nusinersen Injection product records with the FDA, mostly as injection; the earliest marketing or approval year on record is 2016. Brand names on the directory include Spinraza; the rest are generics.
How widely Nusinersen Injection is used (Medicaid data)
A general measure of how commonly Nusinersen Injection is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Nusinersen Injection is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Nusinersen Injection prescribed? Of the 1,601 medications we measure, Nusinersen Injection ranks #1,392 by Medicaid prescriptions — more than 13% of them.
Utilization by Nusinersen Injection product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
5 ML nusinersen 2.4 MG/ML Injection
Summed across the 1 of 1 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1863560
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Nusinersen Injection, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 1 of 1 listed Nusinersen Injection NDCs with Medicaid activity.
Compare Nusinersen Injection products
A representative set of FDA-listed product records for Nusinersen Injection — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Injection | ||||
| 2.4 mg/mL | Intrathecal | Biogen Inc. | NDA | View NDC → |
| 5.6 mg/mL | Intrathecal | Biogen Inc. | NDA | View NDC → |
| 10 mg/mL | Intrathecal | Biogen Inc. | NDA | View NDC → |
Showing 3 of 3 products — FDA National Drug Code Directory. See every product, package size and price: browse all 3 Nusinersen Injection NDCs →
Nusinersen Injection side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Nusinersen Injection — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Nusinersen Injection in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Nusinersen Injection FDA approval history
How Nusinersen Injection went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Nusinersen Injection recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list no Nusinersen recalls since July 2021.
✅No Nusinersen recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 1863556 1 dose form · 3 strengths
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Dose form (SCDF) Injection RxCUI 1863559In current FDA listingsClinical drug / strength (SCD) 5 ML nusinersen 10 MG/MLRxCUI 27399955 ML nusinersen 2.4 MG/MLRxCUI 18635605 ML nusinersen 5.6 MG/MLRxCUI 2740001
Look up RxCUI 1863556 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Nusinersen Injection supply and shortage status
Whether Nusinersen Injection is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
Nusinersen Injection brand names
Nusinersen Injection is sold under one brand name in the FDA directory — Spinraza. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Nusinersen Injection: manufacturers and labelers
One company lists Nusinersen Injection products with the FDA. By number of product records, the largest are Biogen Inc.. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
Nusinersen Injection drug class (RxNorm)
Nusinersen Injection belongs to the Antisense Oligonucleotide class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this Nusinersen Injection page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Biogen Inc. is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →