Final answer:
The best assessment question for a nurse to ask when a client is prescribed finasteride without a known prostate disorder is to inquire if the medication was prescribed for hair loss treatment, as finasteride is also used for treating male pattern hair loss.
Step-by-step explanation:
If a client is prescribed finasteride but does not have a history of prostate disorder, it is important for the nurse to gather more information about the prescription.
A relevant assessment question would be:
"Can you clarify if the finasteride was prescribed for hair loss treatment or for a reason unrelated to prostate health?"
This question helps to clarify the possible indication for the medication, as finasteride is not only used to treat benign prostatic hyperplasia (BPH) but can also be prescribed for androgenetic alopecia, commonly known as male pattern hair loss.