Interaction between escitalopram and risperidone

The ever-increasing use of psychotropic drugs in clinical practice today is a blessing for the patient who can hope to achieve faster remission and possibly a higher rate of cure. However, the flip side is that the use of polypharmacy increases the potential for drug–drug interactions. Escitalopram is a novel antidepressant and there are several reports on its efficacy in the treatment of depression. Reports about its interactions with the cytochrome P450 (CYP 450) enzyme system are relatively few in number. We present a case report of a possible interaction between escitalopram and risperidone. Escitalopram has an inhibitory effect on the CYP 2D6 enzyme. Risperidone is the substrate for this enzyme. In the presence of escitalopram, there is a rise in the levels of risperidone, as evidenced by severe extrapyramidal adverse effects at a low dose of risperidone not normally known to cause extrapyramidal effects.