Risdiplam
Spinal muscular atrophy (SMA) therapies
Spinal muscular atrophy (SMA) therapies
First oral drug for spinal muscular atrophy: a small molecule that modifies SMN2 splicing to raise full-length SMN protein. It may harm the fetus.
Quick facts
- Group
- Spinal muscular atrophy (SMA) therapies
- Target
- SMN2 pre-mRNA splicing
- Used for
- Spinal muscular atrophy
- Key effects
- Fever · Diarrhoea · Rash and mouth ulcers
- Monitor
- Motor milestones · Fever
- ATC
- M09AX10
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows risdiplam bound to an RNA duplex that models 5′-splice-site recognition, the splicing step it modifies; it is RNA, not a protein.
Risdiplam is a survival of motor neuron 2 (SMN2)-directed RNA splicing modifier. Taken by mouth, it changes how SMN2 pre-mRNA is spliced so that more full-length mRNA is produced. More full-length SMN protein is made, which supports motor neurons and improves muscle strength and movement.
- Taken by mouth once a day
- Acts on SMN2 pre-mRNA splicing
- More full-length SMN mRNA is produced
- More SMN protein: better motor function
Indications
- Spinal muscular atrophy, infantile-onset and later-onset Spinal muscular atrophy →
Adverse effects
Common
- Fever
- Diarrhoea, constipation and vomiting
- Rash and mouth ulcers
- Joint pain
- Urinary and upper respiratory tract infections, pneumonia in infants
Contraindications
- Hypersensitivity to risdiplam or to any of its ingredients
Key interactions
- Substrates of multidrug and toxin extrusion (MATE) transporters
- Risdiplam may raise their plasma levels; the combination is avoided.
What is monitored
- Pregnancy test before starting when relevant
- Motor milestones and motor-function scales
- Fever, diarrhoea, rash and infections
Administration and safety
- The oral solution is prepared by the pharmacist and measured with an oral syringe; it is given soon after drawing it up.
- In breastfed infants it is given before or after a feed, never mixed with formula or milk.
- Tablets are swallowed whole or dispersed only in non-chlorinated drinking water as instructed.
- A dose is not repeated if vomited; the next dose is given at the usual time.
Pregnancy and breastfeeding
It may harm the fetus: a pregnancy test may be required before starting, and contraception is used during treatment and for at least one month afterwards.
Nursing care
- Teach carers to measure the solution with the oral syringe and to rinse with water after the dose.
- Discuss effective contraception during treatment and for at least a month after.
- Watch for fever, rash, mouth ulcers, diarrhoea and signs of infection.
- Check the medication list for MATE transporter substrates.
Pharmacokinetics
- Absorption
- Oral solution or tablet, once daily, with or without food.
Test yourself
Think of the answer, then tap the question to see it.
What kind of drug is risdiplam?
An oral small molecule that modifies SMN2 RNA splicing to increase full-length SMN protein.
What was new about risdiplam when it was approved?
It was the first oral drug for spinal muscular atrophy.
Which pregnancy advice comes with risdiplam?
It may harm the fetus; a pregnancy test may be needed and contraception is used during treatment and for at least one month after.
Which transporter substrates should be avoided with risdiplam?
Substrates of multidrug and toxin extrusion (MATE) transporters, whose levels risdiplam may raise.
Connections
← Back to the class: Spinal muscular atrophy (SMA) 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: Risdiplam: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); FDA Approves Oral Treatment for Spinal Muscular Atrophy (U.S. Food and Drug Administration, 2020); RCSB PDB - 8R62: Solution structure of Risdiplam bound to the RNA duplex formed upon 5'-splice site recognition (RCSB Protein Data Bank, 2024); ATCDDD - ATC/DDD Index (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.