Increased Plasma Valproate Concentrations When Coadministered with Guanfacine

Autor: Roomana M. Sheikh, Paul J. Ambrosini
Rok vydání: 1998
Předmět:
Zdroj: Journal of Child and Adolescent Psychopharmacology. 8:143-147
ISSN: 1557-8992
1044-5463
DOI: 10.1089/cap.1998.8.143
Popis: A preliminary clinical observation suggests the possibility of changes in valproate level when coadministered with guanfacine. Two pediatric inpatients (8 and 9 years of age) were treated with valproic acid and guanfacine concurrently. In one child, when guanfacine was tapered and discontinued, the plasma valproate concentration decreased by 41% from 128 microg/mL to 76 microg/mL. In the other case, studied in an ABA design, the child exhibited a rapid increase in plasma valproate levels while guanfacine was administered. It is proposed that guanfacine may affect the pharmacokinetics of valproic acid and lead to a significant increase in valproate plasma levels when used concurrently with this agent. The mechanism of this proposed interaction may involve drug-drug competition at the level of hepatic glucuronidation (conjugation), although shifts in protein binding cannot be ruled out.
Databáze: OpenAIRE