A nurse is caring for a client who has diabetes mellitus and is taking pioglitazone. The nurse should plan to monitor the client for which of the following adverse effects?

Pioglitazone is a thiazolidinedione antidiabetic agent that enhances insulin sensitivity by activating the peroxisome proliferator-activated receptor-gamma. It primarily addresses insulin resistance in peripheral tissues, but its use is restricted in patients with established heart failure due to risk of volume overload. Rationale: A. Fluid retention is a significant adverse effect of pioglitazone because the medication promotes sodium reabsorption in the renal distal tubules. This expanded plasma volume can lead to peripheral edema and potentially precipitate or worsen heart failure in susceptible individuals. The nurse must monitor the client for rapid weight gain, dyspnea, and bilateral lower extremity swelling during the course of therapy. B. Tinnitus is not a recognized adverse effect associated with the use of thiazolidinediones like pioglitazone. It is more commonly linked to ototoxic medications such as aminoglycosides or high-dose salicylates. A client reporting ringing in the ears while taking pioglitazone should be evaluated for other pharmacological or physiological causes unrelated to their antidiabetic regimen. C. Insomnia is not a typical side effect of pioglitazone therapy, as the medication does not exert stimulatory effects on the central nervous system. Patients with diabetes may experience sleep disturbances due to nocturnal hyperglycemia or hypoglycemia, but pioglitazone itself does not disrupt the sleep-wake cycle. The nurse should investigate alternative causes if the client reports difficulty sleeping. D. Orthostatic hypotension is not associated with pioglitazone; in fact, the fluid retention caused by the drug would be more likely to support or slightly increase blood pressure. Amlodipine or nitrates are more likely to cause postural drops in pressure. Monitoring for dizziness upon standing is not a priority specific to the safety profile of thiazolidinedione medications.