Final answer:
Cynthia dispensed promethazine to the patient, which is an antiemetic and would help with his nausea symptoms after surgery.
Step-by-step explanation:
Cynthia most likely dispensed promethazine to the patient, Erik. Promethazine is known for its antiemetic (preventing vomiting) and antihistaminic effects, which would help alleviate Erik's nausea post-surgery. The drugs fexofenadine, tetracycline, and insulin glargine, which were prepared for other patients, are not typically used for treating nausea. Fexofenadine is an antihistamine used for allergies, tetracycline is an antibiotic, and insulin glargine is a long-acting insulin used for diabetes management.