Adding quetiapine to valproic acid.
- Valproic acid is principally metabolized by CYP2C9, CYP2C19, CYP2A6 and UDP-glucuronosyltransferases. Valproic acid is an inhibitor of the enzymes CYP2C9, epoxide-hydroxylase and UDP-glucuronosyltransferases.
- Quetiapine is principally metabolized by CYP3A4 to active and inactive metabolites.
- This combination of drugs may have possible synergistic effects. However, this combination will also have additive side effects. Dose adaptation will be recommended for this combination. 
- Start quetiapine according to the general dosing advice.
- During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. 
- Farmacotherapeutisch Kompas; Toxicologie (dutch)
- Farmacotherapeutisch Kompas - valproinezuur (dutch)
- KNMP; Informatorium Medicamentorum 2015; Monografie "valproaat" (Dutch)
Cite error: Invalid
<ref>tag; name "informatorium" defined multiple times with different content
- NVZA; Toxicology.org; Monografie 73 (dutch)
- Woods SW Chlorpromazine equivalent doses for the newer atypical antipsychotics J Clin Psychiatry 2003;64:663-667
- Drugs.com quetiapine-fumarate
- Vieta E at al, Efficacy and safety of quetiapine in combination with lithium or divalproex for maintenance of patients with bipolar I disorder (international trial 126). J Affect Disord. 2008 Aug;109(3):251-63. Epub 2008 Jun 24
- Interactions between quetiapine and valproic acid on drugs.com
The editors of psychiatrienet.nl take the greatest care to provide up-to-date and accurate information on this site. Nevertheless, mistakes and omissions cannot be entirely excluded. No rights devolve from the information provided. The editors and other providers of information to this site accept no responsibility for the content of this site or for the information provided therein; neither do they accept responsibility for possible damages which may derive from the use of the information on this site or from the linked sites. The editorial board accepts no responsibility for the content of the (linked) sites, for access to them, or for the products and services on these sites, nor for the occurrence of errors, viruses, and/or disruptions in service.