Final answer:
Thiazolidinediones would not be appropriate for a client with CHF due to the risk of worsening heart failure symptoms.
Step-by-step explanation:
For a client with CHF (congestive heart failure), the category of oral hyperglycemic medication that would NOT be appropriate is the Thiazolidinediones. Thiazolidinediones, such as Rosiglitazone and Pioglitazone, are known to cause fluid retention and can worsen symptoms of heart failure. These medications should be avoided in patients with CHF as they can increase the risk of cardiovascular events and fluid overload. It is important for healthcare providers to consider the patient's comorbidities and individual response to medications when prescribing oral hyperglycemic agents.