Final answer:
Carbamazepine is contraindicated for a 58-year-old man with bipolar disorder, leukemia, and testicular cancer.
Step-by-step explanation:
The medication that is contraindicated as monotherapy for a 58-year-old man with bipolar disorder with a background history of leukemia and testicular cancer is carbamazepine.
Carbamazepine is a mood stabilizer commonly used to treat bipolar disorder. However, it can lower the white blood cell count and may worsen symptoms in patients with a history of leukemia. Therefore, it is not recommended for this particular patient.