Final answer:
The main concern when administering nitroprusside to patients with poor kidney function is the risk of accumulation of toxic metabolites such as thiocyanate and cyanide, potentially leading to toxicity.
Step-by-step explanation:
When administering nitroprusside, particularly to patients with poor kidney function, there is a significant concern for the accumulation of toxic metabolites, specifically thiocyanate and cyanide, which can lead to thiocyanate toxicity or cyanide poisoning. These byproducts are normally cleared by the kidneys, and compromised renal function can lead to their build-up in the bloodstream. It is important to closely monitor levels of these metabolites and adjust the medication dosage accordingly. Patients receiving nitroprusside infusion should be observed for signs of toxicity such as confusion, hyperreflexia, and convulsions, which may necessitate the discontinuation of the drug.