Formulary
Sapropterin dihydrochloride: Indications, Dosing, Side Effects and Interactions
Sapropterin is synthetic 6R-tetrahydrobiopterin (6R-BH4), a cofactor for phenylalanine hydroxylase, and therefore restores the activity of phenylalanine...
MedNext Academy | 3 min read
Sapropterin dihydrochloride: Indications, Dosing, Side Effects and Interactions
Sapropterin is synthetic 6R-tetrahydrobiopterin (6R-BH4), a cofactor for phenylalanine hydroxylase, and therefore restores the activity of phenylalanine...
Drug action
Sapropterin is synthetic 6R-tetrahydrobiopterin (6R-BH4), a cofactor for phenylalanine hydroxylase, and therefore restores the activity of phenylalanine hydroxylase and reduces phenylalanine concentration in the blood.
Indications and dose
**Phenylketonuria (adjunct to dietary restriction of phenylalanine) (specialist use only)**
- **Adult** (By Mouth): Initially 10 mg/kg once daily, adjusted according to response; usual dose 5-20 mg/kg once daily, dose to be taken preferably in the morning.
**Tetrahydrobiopterin deficiency (adjunct to dietary restriction of phenylalanine) (specialist use only)**
- **Adult** (By Mouth): Initially 2-5 mg/kg daily in 2-3 divided doses, adjusted according to response; maximum 20 mg/kg per day.
**Phenylketonuria (adjunct to dietary restriction of phenylalanine) (specialist use only) for sapropterin dihydrochloride**
- **Neonate** (By mouth): Initially 10 mg/kg once daily, adjusted according to response; usual dose 5-20 mg/kg once daily, dose to be taken preferably in the morning.
- **Child** (By mouth): Initially 10 mg/kg once daily, adjusted according to response; usual dose 5-20 mg/kg once daily, dose to be taken preferably in the morning.
**Tetrahydrobiopterin deficiency (adjunct to dietary restriction of phenylalanine) (specialist use only) for sapropterin dihydrochloride**
- **Neonate** (By mouth): Initially 2-5 mg/kg daily in 2-3 divided doses, adjusted according to response; maximum 20 mg/kg per day.
- **Child** (By mouth): Initially 2-5 mg/kg daily in 2-3 divided doses, adjusted according to response; maximum 20 mg/kg per day.
Cautions
History of convulsions
Side effects
Common or very common Cough; diarrhoea; gastrointestinal discomfort; headache; laryngeal pain; nasal complaints; nausea; vomiting Frequency not known Gastrointestinal disorders; rash
Interactions
**Other interactions (4):**
- Although concomitant administration of inhibitors of dihydrofolate reductase (e.g.
- Caution is recommended during concomitant use of sapropterin dihydrochloride with all medicinal products that cause vasodilation, including those administered topically, by affecting nitric oxide...
- Caution should be exercised when prescribing sapropterin dihydrochloride to patients receiving treatment with levodopa.
- Cases of convulsion, exacerbation of convulsion, increased excitability and irritability have been observed during co-administration of levodopa and sapropterin in BH4-deficient patients.
Pregnancy
Manufacturer advises caution-consider only if strict dietary management inadequate.
Breast feeding
Manufacturer advises avoid-no information available.
Hepatic impairment
Manufacturer advises caution (no information available).
Renal impairment
Manufacturer advises caution-no information available.
Medicinal forms
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
Inside MedNext for this topic
- 411 MedNext-authored chapters
- 80,000+ MCQ bank
- 15 study modes
- Growing visual cheat sheets
Study modes
- Notes
- MCQ
- Audio
- Video
- Visual
- 3D Anatomy
- Trace
- Flashcards
- Mnemonics
- Image Bank
- Clinical
- Microscopy
- Audio QBank
- Cadaver
- Book Match
Continue reading
Subject HubPharmacology Hub
All pharmacology resources in one place.
Drug SchedulesIndian Drug Schedules
Schedule H, H1, X and G classifications.
FormularyBrowse all drugs
Search 1,850+ drug profiles.
Study Sapropterin dihydrochloride in the MedNext app
Challenge yourself with targeted pharmacology MCQs on this drug class. Every explanation links back to the chapter that teaches the concept.
Start drug challengeExplore the full formulary

