Section 16 · Monograph
Nusinersen
Reviewed Nov 2026FDA label
SpinrazaAntisense oligonucleotide
- Forms
- Intrathecal: 12mg/5mL (2.4mg/mL) vial
- Dose
- Label (rev 3/2026) has two regimens: LOW DOSE 12mg x4 loading (first 3 at 14-day intervals, 4th 30 days after the 3rd), then 12mg every 4 months | HIGH DOSE two 50mg loading doses 14 days apart, then 28mg every 4 months starting 4 months after last loading dose
- MOA
- Modifies SMN2 splicing to ↑functional SMN protein
Indications
- Treatment of spinal muscular atrophy (SMA) in pediatric and adult patientsFDA-labeled
Mechanism of Action
- SMN2-directed antisense oligonucleotide that modifies pre-mRNA splicing to include exon 7, increasing full-length functional SMN protein
Full Dosing
Adult / usual
- Label (rev 3/2026) lists two regimens: LOW DOSE 12mg x4 loading doses (first three 14 days apart, fourth 30 days after the third), then 12mg every 4 months
- HIGH DOSE: two 50mg loading doses 14 days apart, then 28mg every 4 months starting 4 months after the last loading dose
- Intrathecal bolus over 1-3 minutes after removing 5mL of CSF; consider sedation and imaging guidance in younger patients
- Obtain platelet count, coagulation tests and quantitative urine protein before each dose
Contraindications
- None listed in labeling
Drug Interactions
- No formal drug-interaction studies reported
Adverse Effects
- Respiratory infections, constipation, vomiting
- Post-lumbar-puncture syndrome (headache, back pain)
- Thrombocytopenia and coagulation abnormalities
- Renal toxicity (proteinuria)
- Communicating hydrocephalus reported postmarketing
Monitoring Parameters
- Platelets, coagulation tests and urine protein before each dose
- Signs of hydrocephalus
- Motor milestones and respiratory status
Pregnancy & Lactation
- Animal data show developmental toxicity; limited human data
- Unknown whether present in human milk