Drug General Information (ID: DDIIUEXDT0)
Drug Name			Valproic acid		Drug Info		Phenylbutyric acid		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Anticonvulsants				Antihyperammonia Agents
Structure

Mechanism of Valproic acid-Phenylbutyric acid Interaction (Severity Level: Major)
Antagonize the effect of anti-hyperammonemia agents Click to Show/Hide Mechanism Graph
Drug Name		Valproic acid				Phenylbutyric acid
Mechanism		Hyperammonemia				Anti-hyperammonemia agent
Key Mechanism Factor 1
		Factor Name		Anti-hyperammonemia agents
		Factor Description		Anti-hyperammonemic agents may be less effective in acute hyperammonemia, leading to the development of hyperammonemic encephalopathy, which can sometimes be fatal.
Mechanism Description		Antagonize the effect of Phenylbutyric acid when combined with Valproic acid

Recommended Action
Management		Valproic acid should generally not be given to patients receiving phenylbutyrate therapy, as the use of valproic acid is considered contraindicated in patients with urea cycle disorders.

References
1	Product Information. Depakene (valproic acid). Abbott Pharmaceutical, Abbott Park, IL.
2	Product Information. Ravicti (glycerol phenylbutyrate). Hyperion Therapeutics Inc, South San Francisco, CA.
3	Product Information. Depakote (divalproex sodium). Abbott Pharmaceutical, Abbott Park, IL.