Adding valproic acid to risperidone.
- Risperidone is principally metabolized by CYP2D6 to an active metabolite 9-OH-risperidone (paliperidone).
- 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.
Start valproic acid
- Coadministration with risperidone may alter the serum concentrations of valproic acid, although data are conflicting.
- Start valproic acid according to the general dosing advice.
- Dose-related generalised oedema is reported. 
- Antipsychotics lower the seizure threshold and may antagonise the anticonvulsant effect of valproate. 
KNMP; Informatorium Medicamentorum 2015; Monografie "risperidon" (Dutch)
Cite error: Invalid
<ref>tag; name "informatorium" defined multiple times with different content
- Woods SW; Chlorpromazine equivalent doses for the newer atypical antipsychotics J Clin Psychiatry 2003;64:663-667
- The Lundbeck Institute; Psychotropics; Terminal Plasma Half-lives
- Farmacotherapeutisch Kompas; Toxicologie (dutch)
- Farmacotherapeutisch Kompas - valproinezuur (dutch)
- Sanders and Lehrer, Edema associated with addition of risperidone to valproate treatment. J Clin Psychiatry. 1998 Dec;59(12):689-90.
- Bazire S, Psychotropic Drug Directory 2007, HealthComm UK Limited, Aberdeen, 2007.
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