Final answer:
The nurse should clarify the prescription of Morphine sulfate for pain relief due to its potential to further depress the respiratory system in a post-craniotomy patient with a low respiratory rate.
Step-by-step explanation:
The nurse should clarify the prescription for Morphine sulfate 2 mg IV bolus PRN every 2 hr for pain with the provider. Morphine is an opioid that can depress the respiratory system, and since the patient has just undergone a craniotomy and has a respiratory rate of 12, which is at the lower end of the normal range (12-20 breaths per minute), further depression of the respiratory rate could be dangerous. The other medications, including Dexamethasone for inflammation, Ondansetron (Zofran) for nausea, and Phenytoin for seizure prevention, are commonly used postoperatively and do not directly depress respiration. However, it is essential to monitor all medications' side effects and interactions in a post-craniotomy patient.