- Author: Georgianne L Arnold, MD; Chief Editor: Bruce Buehler, MD more...
Sapropterin may decrease plasma phenylalanine levels.
Some children respond to BH4 supplementation. Synthetic BH4 (sapropterin) is now approved by the US Food and Drug Administration. Also consider restricting use of drugs and food that contain aspartame.
Synthetic form of tetrahydrobiopterin (BH4), the cofactor for the enzyme phenylalanine hydroxylase (PAH). PAH hydroxylates phenylalanine through an oxidative reaction to form tyrosine. PAH activity is absent or deficient in patients with PKU. Treatment with BH4 can activate residual PAH enzyme, improve normal oxidative metabolism of phenylalanine, and decrease phenylalanine levels in some patients. Indicated to reduce blood phenylalanine levels in patients with hyperphenylalaninemia caused by BH4-responsive PKU. Used in conjunction with a phenylalanine-restricted diet.
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