A client is receiving furosemide (Lasix). The nurse should monitor for which adverse effect of the medication?

A. Nausea: Nausea can occur with many medications but is not a primary concern with furosemide therapy. It does not reflect the major physiologic changes caused by the drug, such as fluid or electrolyte loss. Monitoring only for nausea may overlook more serious effects related to volume depletion. B. Increased urinary output: This effect is expected because furosemide promotes diuresis by inhibiting sodium and chloride reabsorption. Higher urine output indicates that the medication is working rather than causing harm. C. Dizziness Lightheadedness: Furosemide can cause significant fluid loss and lower blood pressure, leading to dizziness or lightheadedness from reduced circulating volume. These symptoms may indicate hypotension or dehydration, requiring prompt assessment. Monitoring for these effects helps prevent falls and cardiovascular instability. D. Gastric upset: Mild gastric irritation may occur, but it is not a key adverse effect associated with furosemide. Instead, the drug’s main risks involve electrolyte imbalances and volume depletion. Focusing on gastric discomfort would not detect potentially serious complications.