risdiplam: clinical use

Prescribing considerations

• Initiation should be by a clinician experienced in managing SMA.
• Select formulation according to licensed criteria, swallowing ability and need for enteral-tube administration.
• Verify pregnancy status and provide contraception, fetal-risk and male-fertility counselling before treatment.
• Severe hepatic impairment has not been studied and may increase exposure.
• The oral solution contains isomalt and sodium benzoate; consider hereditary fructose intolerance and potential increased jaundice in newborn babies.

Contraindications and cautions

• Hypersensitivity to risdiplam or any formulation excipient.
• The isomalt-containing oral solution should not be used in hereditary fructose intolerance.

Monitoring

• Assess clinical response, motor function and tolerability through the specialist SMA service.
• Monitor new rashes for possible cutaneous vasculitis.
• Monitor for toxicity from metformin or other MATE1 or MATE2-K substrates when co-administration cannot be avoided.

Clinical pharmacology

Risdiplam modifies SMN2 pre-mRNA splicing to increase functional SMN protein and distributes systemically, including across the blood-brain barrier.

Formulation and product differences

• The oral solution is prepared by a healthcare professional and can be given through nasogastric or gastrostomy tubes.
• Tablets may be swallowed whole or dispersed in room-temperature water, but must not be chewed, cut, crushed or given through a feeding tube.
• Tablets require protection from moisture; the oral solution requires refrigerated storage and protection from light.

Oral solution

Route: Oral

Strengths: 0.75 mg/mL

Tablet

Route: Oral

Strengths: 5 mg