ANTIPSYCHOTICS AND DARIFENACIN

Darifenacin increases the levels of CYP2D6 substrates such as the tricyclics (imipramine AUC increased by 70%). The manufacturers therefore advise caution with other CYP2D6 substrates, and specifically name thioridazine.
If the combination is used it would be prudent to closely monitor for thioridazine adverse effects, and consider the possibility of ventricular arrhythmias.