Final answer:
The nurse should monitor the patient's blood glucose levels, as corticosteroids can lead to hyperglycemia.
Step-by-step explanation:
The nurse should plan to carefully monitor the patient's blood glucose levels when they are receiving immunosuppressant therapy, including corticosteroids, after renal transplantation. This is due to the fact that corticosteroids, which are glucocorticoids such as cortisol and cortisone, increase blood glucose levels by stimulating glucose synthesis and the release of fatty acids from adipose tissue. Moreover, corticosteroids can cause hyperglycemia as a side effect, thus requiring regular monitoring of blood glucose levels to manage and prevent diabetic complications.