[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Spinal muscular atrophy (SMA) therapies](https://durgical.com/en/pharmacology/classes/spinal-muscular-atrophy-therapies/) › Nusinersen

# Nusinersen

## Spinal muscular atrophy (SMA) therapies?

Spinal muscular atrophy (SMA) therapies

Antisense oligonucleotide injected by lumbar puncture for spinal muscular atrophy. It makes SMN2 produce more full-length SMN protein.

Updated Nov 1, 2026

## Quick facts

**Group**
[Spinal muscular atrophy (SMA) therapies](https://durgical.com/en/pharmacology/classes/spinal-muscular-atrophy-therapies/)

**Target**
SMN2 pre-mRNA (intronic splicing silencer ISS-N1 in intron 7)

**Used for**
Spinal muscular atrophy in infants

**Key effects**
Headache · Respiratory infections · Constipation

**Monitor**
Growth in infants

**ATC**
M09AX07

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Nusinersen is an 18-base 2′-O-methoxyethyl phosphorothioate antisense oligonucleotide. Injected into the cerebrospinal fluid, it is taken up by motor neurons and pairs by Watson–Crick base pairing with ISS-N1, an intronic splicing silencer just after exon 7 of the SMN2 pre-mRNA. This blocks the hnRNP repressor proteins, exon 7 is kept in the mature mRNA, and more full-length, functional SMN protein is made.

- Injected intrathecally into the cerebrospinal fluid
- Pairs with the ISS-N1 silencer in SMN2 intron 7
- hnRNP repressors cannot bind: exon 7 is included
- More full-length SMN protein: motor neurons survive

## Indications

- Spinal muscular atrophy in infants, children and adults [Spinal muscular atrophy →](https://durgical.com/en/conditions/spinal-muscular-atrophy/)

## Adverse effects

### Common

- Headache, back pain and vomiting related to lumbar puncture
- Respiratory infections: runny nose, sore throat, cough
- Constipation
- Fever and falls

### Serious (rare, important)

- Unusual bleeding or bruising
- Kidney damage: foamy, pink or brown urine, swelling of hands, face or feet
- Slower growth in infants

## Contraindications

- Hypersensitivity to nusinersen or to any component of the solution

## Key interactions

**Other medicines**
No clinically important interactions are listed in the patient information; every medicine and supplement is still reviewed before each dose.

## What is monitored

- Blood and urine tests before starting and before each dose, looking for bleeding problems and kidney damage
- Growth in infants
- Motor function scales to judge response

## Administration and safety

- Given intrathecally by a doctor experienced in lumbar puncture, in an office or clinic.
- Loading doses come first, then maintenance doses at regular intervals; missed doses are rescheduled promptly.

## Pregnancy and breastfeeding

Data are limited; pregnancy or breastfeeding is reported to the treating doctor.

## Nursing care

- Before each dose, check that the blood and urine results have been reviewed.
- After the lumbar puncture, watch for headache, back pain and vomiting.
- Teach carers to report bleeding, bruising, changes in urine or swelling.
- Track the child's weight and length on growth charts.

## Pharmacokinetics

**Absorption**
Given intrathecally by lumbar puncture because it does not cross the blood–brain barrier well.

**Distribution**
Taken up by neurons and glial cells throughout the spinal cord and brain; the part that reaches the blood binds plasma proteins.

## Memory aid

NUSINERSEN «NUdges SpliciNg»: it covers the ISS-N1 brake so exon 7 stays in.

## Test yourself

Think of the answer, then tap the question to see it.

## What sequence does nusinersen bind?

The ISS-N1 intronic splicing silencer just downstream of exon 7 in SMN2 pre-mRNA.

## What is the result of nusinersen binding?

Exon 7 is included in SMN2 mRNA, so more full-length SMN protein is made.

## By what route is nusinersen given, and why?

Intrathecally by lumbar puncture, because the oligonucleotide does not cross the blood–brain barrier well.

## Which laboratory problems are checked before each nusinersen dose?

Bleeding problems and kidney damage, with blood and urine tests.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/nusinersen/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 3

- [Risdiplam](https://durgical.com/en/pharmacology/risdiplam/)
- [Onasemnogene abeparvovec](https://durgical.com/en/pharmacology/onasemnogene-abeparvovec/)
- [Tofersen](https://durgical.com/en/pharmacology/tofersen/)

## Related conditions 1

- [Spinal muscular atrophy](https://durgical.com/en/conditions/spinal-muscular-atrophy/)

[← Back to the class: Spinal muscular atrophy (SMA) therapies](https://durgical.com/en/pharmacology/classes/spinal-muscular-atrophy-therapies/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Nusinersen Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a617010.html) (MedlinePlus (U.S. National Library of Medicine), 2018); [Nusinersen as a Therapeutic Agent for Spinal Muscular Atrophy](https://pmc.ncbi.nlm.nih.gov/articles/PMC7105407/) (Yonsei Medical Journal, via PubMed Central, 2020); [SMN2 gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/smn2/) (MedlinePlus Genetics (U.S. National Library of Medicine), 2018); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=M09AX07) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/nusinersen/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/nusinersen/