A 32-year-old patient, with a history of neurocardiogenic syncope, delivered a healthy infant via elective cesarean section. After the delivery, the staff anesthesiologist exited the room and left an anesthesia resident to care for the patient. When the patient’s blood pressure began to drop, the resident decided to administer ephedrine to restore blood pressure. She could not find the ephedrine, so she decided to use neosynephrine, choosing a dose of 500mg (10 times the usual dose) without diluting it. After receiving the medication, the patient experienced hypertension, tachycardia, and pulmonary edema. She was transferred to the intensive care unit for an extended stay and requires lifelong monitoring for cardiac-related complications. The resident left the program following this event.