About sapropterin
Synthetic tetrahydrobiopterin (BH4)
Used for
- Helps lower blood phenylalanine in some people with phenylketonuria (PKU).
- Treats certain forms of tetrahydrobiopterin deficiency.
Usual adult dose
Usually 10–20 mg/kg once daily for PKU; dose is adjusted to blood phenylalanine response. For BH4 deficiency, commonly 2–5 mg/kg daily, adjusted by a specialist.
Usual dose in children
Usually 10–20 mg/kg once daily for PKU; dose is adjusted to blood phenylalanine response. For BH4 deficiency, commonly 2–5 mg/kg daily, adjusted by a specialist.
Common side effects
- Headache
- Runny or blocked nose
- Sore throat or cough
- Diarrhea or stomach pain
Important warnings
- Requires blood phenylalanine monitoring and continued dietary management.
- Not everyone with PKU responds; response should be assessed by a specialist.
- Low blood phenylalanine can occur, especially in young children.
- Seek urgent care for signs of a severe allergic reaction.
Pregnancy
Pregnancy data are limited. Use requires specialist assessment, balancing potential benefits and risks; maintaining appropriate phenylalanine control is important.
Breastfeeding
It is not known whether sapropterin passes into breast milk. Discuss use with a specialist.
Interactions
- Levodopa may increase the risk of nervous-system effects, including seizures.
- Medicines affecting nitric oxide pathways may increase low blood pressure risk.
- Other medicines that lower phenylalanine may increase the risk of low levels.
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 It may be incomplete or out of date.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.