A pregnant client is receiving magnesium sulfate therapy for the control of preeclampsia. A nurse discovers that the client is encountering toxicity from the medication in which of the following assessments?

Correct Answer: A

Rationale: Magnesium sulfate toxicity can cause respiratory depression, which is indicated by a respiratory rate of 10 breaths per minute or less. This is a life-threatening complication requiring immediate intervention. Deep tendon reflexes are typically absent in severe toxicity, not present. A urine output of 25 ml/hr may indicate renal impairment but is not specific to magnesium toxicity. A serum magnesium level of 7 mEq/L is elevated but does not alone confirm toxicity without clinical symptoms. Therefore, respiratory depression is the key indicator.

Correct Answer: B

Rationale: Levodopa treats Parkinson's by crossing the blood-brain barrier and converting to dopamine, but peripheral metabolism by dopa decarboxylase reduces its availability and causes side effects like nausea. Carbidopa, a peripheral dopa decarboxylase inhibitor, doesn't cross into the CNS, so it prevents levodopa breakdown outside the brain, increasing its CNS entry and efficacy. It doesn't stimulate dopamine receptors—levodopa's metabolite does that. Absorption isn't directly enhanced; bioavailability improves due to less peripheral loss. Peripheral dopamine production decreases with carbidopa, not increases, reducing side effects. COMT inhibition (e.g., entacapone) is a separate strategy. By blocking peripheral conversion, carbidopa ensures more levodopa reaches the brain, optimizing therapy and minimizing adverse effects.

Correct Answer: D

Rationale: Post-transplant immunosuppression targeting mTOR points to sirolimus . It inhibits T-cell proliferation downstream of IL-2, distinct from azathioprine , cyclosporine , methotrexate , and prednisolone (E). Sirolimus's unique action prevents rejection effectively.

Correct Answer: A

Rationale: For a 79-year-old patient taking a diuretic for hypertension, the nurse should know that extra precautions are necessary for preventing orthostatic hypotension and potential falls. Orthostatic hypotension refers to a drop in blood pressure that occurs when standing up from a sitting or lying down position. This can lead to dizziness and an increased risk of falls, particularly in elderly individuals. Therefore, the teaching point about taking extra precautions when standing up is critical to emphasize for this patient to ensure their safety and well-being. Option A is the correct choice as it highlights the importance of this teaching point for the patient's care.

Correct Answer: C

Rationale: All calcium channel blockers (CCBs) like verapamil and nifedipine are orally active, so that's false. Half-lives vary (e.g., nifedipine ~2-5 hours, diltiazem longer), not uniformly 8-12 hours, making that false. They block L-type voltage-gated calcium channels, reducing vascular and cardiac contractility, a true statement. They relax bronchiolar smooth muscle, not unaffected, so that's false. Dihydropyridines cause reflex tachycardia, not bradycardia. The L-type blockade is their unifying mechanism, key to antihypertensive and antianginal effects.