Final answer:
Sertraline and venlafaxine taken together can cause serotonin syndrome.
Step-by-step explanation:
The patient has been prescribed sertraline and venlafaxine, which are both medications used for the treatment of depression. When taken together, these medications can cause a condition known as serotonin syndrome. Serotonin syndrome occurs when there is an excess of serotonin in the central nervous system, leading to symptoms such as agitation, hallucinations, rapid heartbeat, high blood pressure, and fever.