Review Question - QID 108893

A 67-year-old male presents to the emergency department with sudden onset shortness of breath and epigastric pain. The patient has a past medical history of GERD, obesity, type 2 diabetes mellitus, anxiety, glaucoma, and irritable bowel syndrome. His current medications include omeprazole, insulin, metformin, lisinopril, and clonazepam as needed. The patient's temperature is 99.5°F (37.5°C), pulse is 112/min, blood pressure is 90/70 mmHg, respirations are 18/min, and oxygen saturation is 95% on room air. On physical exam, the patient's lungs are clear to auscultation bilaterally. Jugular venous distention is notable and cardiac auscultation is not revealing. The patient is given a bolus of fluids and his pulse becomes 80/min with a blood pressure of 105/75 mmHg. The patient is then started on beta-blockers, oxygen, nitroglycerin, morphine, IV fluids, and aspirin. Repeat vitals demonstrate a blood pressure of 80/65 mmHg. Which of the following is the best explanation for this patient's decrease in blood pressure after medication administration?