Answer:
Option C, thioridazine
Step-by-step explanation:
The antipsychotic medication thioridazine, option C, has a listed side effect of causing hypotension as well as other possible cardiovascular side effects and adverse reactions, and as such can have additive hypotension effects when used with antihypertensive medications. Because of this, the nurse should be aware and ensure that the prescribing provider is notified to possibly change the patient's pharmacotherapy.
Ibuprofen can decrease the effectiveness of antihypertensive medications but this does not necessarily indicate cautious use like thioridazine does. Diphenhydramine can also cause hypotension, however, it is not as common of an adverse reaction as thioridazine, nor are antihypertensives a listed drug-drug interaction with this medication. Somewhat related, there are no specifically listed drug-drug interactions with vitamins and antihypertensives like ACE inhibitor lisinopril. This rules out options A, B, and D.