Correct Answer: A

Rationale: Spironolactone is a potassium-sparing diuretic, so the nurse should monitor the client for hyperkalemia, which can cause muscle weakness and cardiac dysrhythmias.

Correct Answer: C

Rationale: Captopril should be taken on an empty stomach for better absorption. The client should be instructed to take it 1 hour before or 2 hours after meals to optimize its effectiveness. Taking it with food can reduce its absorption and efficacy.

Correct Answer: A

Rationale: In a client with a plasma lithium level of 2.1 mEq/L, immediate gastric lavage is appropriate for severe toxicity. Gastric lavage can help lower the client's lithium level by removing the unabsorbed lithium from the stomach.

Correct Answer: A

Rationale: Spironolactone is a potassium-sparing diuretic. The client should avoid salt substitutes because they often contain potassium, which could lead to hyperkalemia. Hyperkalemia, or high levels of potassium in the blood, is a potential side effect of spironolactone, and ingesting additional potassium from salt substitutes can exacerbate this risk.

Correct Answer: C

Rationale: Furosemide is a diuretic that can lead to orthostatic hypotension, causing dizziness and falls. Instructing the client to change positions slowly helps prevent these adverse effects by allowing the body to adjust to postural changes gradually, reducing the risk of significant blood pressure drops upon standing up quickly.