Sapropterin
Mechanism :
Sapropterin is a synthetic form of the cofactor BH4 (tetrahydrobiopterin) for the enzyme phenylalanine hydroxylase.
Indication :
- To reduce blood phenylalanine levels in patients with hyperphenylalaninemia caused by tetrahydrobiopterin (BH4)-responsive PKU.
Contraindications :
Hypersensitivity to sapropterin or any component of the formulation.
Dosing :
≥1 month:
Initial: 10 to 20 mg/kg PO once daily. Maintenance range: 5 to 20 mg/kg once daily. Adjust after 1 month based on blood phenylalanine levels.
Adverse Effect :
Headache, rhinorrhea, diarrhea, vomiting, pharyngolaryngeal pain, cough, rhinitis.
Interaction :
Levodopa: Sapropterin may enhance the adverse/toxic effect of Levodopa.
Methotrexate: May decrease the serum concentration of Sapropterin.
Phosphodiesterase 5 Inhibitors: Sapropterin may enhance the hypotensive effect of Phosphodiesterase 5 Inhibitors.
Hepatic Dose :
Monitor liver function closely. No dose adjustment recommended.