Valproic acid

Pharmacogenomic Information in the Context of the FDA-Approved Drug Label*

The FDA recommends, but does not require, genetic testing prior to initiating treatment with valproic acid.

Excerpt from the valproic acid drug label:

"Stavzor is contraindicated in patients with known urea cycle disorders (UCD). ... Prior to the initiation of Stavzor therapy, evaluation for UCD should be considered in the following patients: 1) those with a history of unexplained encephalopathy, unexplained mental retardation, or history of elevated plasma ammonia or glutamine; 2) those with cyclical vomiting and lethargy, episodic extreme irritability, ataxia, low blood urea nitrogen (BUN), or protein avoidance; 3) those with a family history of UCD or a family history of unexplained infant deaths (particularly males); 4) those with other signs or symptoms of UCD. . . ."

Treatment with valproic acid is contraindicated in patients with known urea cycle disorders (UCD), a group of uncommon genetic abnormalities, since these patients can experience sometimes fatal hyperammonemic encephalopathy following initiation of valproate therapy. UCD results from mutations in one of several genes, including ornithine transcarbamylase (OTC) deficiency and carbamoyl-phosphate synthetase 1 (CPS1) deficiency.

For the complete drug label text with sections containing pharmacogenetic information highlighted, see the Valproic acid drug label PDF.

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