A nurse is caring for a client who is receiving magnesium sulfate IV bolus for preeclampsia. The client's respiratory rate is 6/min and they have absent deep tendon reflexes. Which of the following medications should the nurse anticipate the provider to prescribe?

Rationale for Correct Choices:

• Diltiazem: Diltiazem is a calcium channel blocker commonly used to control ventricular rate in atrial fibrillation. The client’s ECG confirms atrial fibrillation with rapid ventricular response, making rate control a priority to prevent hemodynamic instability.
• Cardiac rhythm: The rapid, irregular heart rate documented on ECG is the primary finding necessitating medication intervention to prevent further complications such as decreased cardiac output or thromboembolism.

Rationale for Incorrect Choices:

• Dopamine: Dopamine is a vasopressor used to support blood pressure in hypotension or shock. While the client’s BP is mildly decreased, the immediate concern is rapid atrial fibrillation rather than hypotensive crisis.
• Furosemide: Furosemide treats fluid overload and edema but does not directly address the acute arrhythmia causing tachycardia and hemodynamic compromise.
• Albuterol nebulizer: Albuterol is used for bronchospasm and respiratory distress related to airway constriction. The client has clear lung sounds, so this is not indicated.
• Alprazolam: Alprazolam can reduce anxiety but does not manage the underlying atrial fibrillation or prevent cardiovascular complications.
• Edema, blood pressure, anxiety, dyspnea: While these are relevant assessments, they are secondary to the urgent need to control the cardiac rhythm in acute atrial fibrillation.

Rationale for correct choices:

• Sodium 124 mEq/L: The client’s serum sodium is critically low, indicating severe hyponatremia, a known serious adverse effect of oxcarbazepine. Hyponatremia can lead to confusion, seizures, and potentially life-threatening neurological complications, requiring immediate provider follow-up and possible medication adjustment or discontinuation.
• Difficulty remembering medication times: Cognitive changes or confusion may indicate central nervous system effects of oxcarbazepine or complications from hyponatremia. This finding signals the need for urgent reassessment and intervention to prevent medication errors or toxicity.
• Nausea/vomiting: Persistent nausea and vomiting, especially after a recent dose increase, may be a sign of drug intolerance, early hyponatremia symptoms, or central nervous system effects. Immediate follow-up is necessary to prevent further complications and dehydration.

Rationale for Incorrect Choices:

• Mild headache: While headaches may occur with oxcarbazepine, the mild nature and recent onset are less urgent compared with severe hyponatremia and neurological symptoms.
• Vital signs (HR 86, BP 110/66, Temp 36.3° C, RR 16): These are slightly lower than baseline but not immediately concerning. The priority is lab abnormality and neurological changes.
• Hct 40%, Hgb 13 g/dL: These values remain within normal limits and do not require immediate intervention.
• Use of oral contraceptives: This is important for counseling because oxcarbazepine can reduce contraceptive efficacy, but it is not an urgent clinical finding compared to hyponatremia.