| add = valproic acid
| info =
* Risperidone is principally metabolized by CYP2D6 to an active metabolite.
* 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.
* 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 =
* Coadministration with risperidone may alter the serum concentrations of valproic acid, although data are conflicting.
