About sapropterin
Synthetic tetrahydrobiopterin (BH4) cofactor
Used for
- Helps lower blood phenylalanine in some people with phenylketonuria (PKU).
- Treats certain BH4-responsive forms of hyperphenylalaninaemia.
Usual adult dose
Usually 10–20 mg/kg once daily for PKU; dose is adjusted using blood phenylalanine levels.
Usual dose in children
Usually 10–20 mg/kg once daily for PKU; dose is adjusted using blood phenylalanine levels.
Common side effects
- Headache
- Runny or blocked nose
- Sore throat
- Diarrhoea or stomach pain
Important warnings
- Continue a phenylalanine-restricted diet when prescribed.
- Blood phenylalanine must be monitored during treatment.
- Low blood phenylalanine can occur, especially in young children.
- Seek urgent care for signs of a severe allergic reaction.
Pregnancy
Pregnancy data are limited; maintaining appropriate blood phenylalanine control is important. Use requires specialist assessment.
Breastfeeding
Information is limited. A clinician should assess treatment while breastfeeding.
Interactions
- Levodopa may increase the risk of seizures or nervous system effects.
- Medicines affecting nitric oxide pathways may increase blood-pressure-lowering effects.
- Use with other phenylalanine-lowering treatments may increase low phenylalanine risk.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.