In a patient receiving intravenous magnesium sulfate for seizures, what is a serious complication the nurse should monitor for?

When administering intravenous magnesium sulfate, particularly for seizure control in conditions like eclampsia, a significant complication to monitor for is bradycardia. Magnesium sulfate acts as a central nervous system depressant and can lead to an increased risk of cardiac events. Bradycardia occurs when the heart rate drops below normal levels, which can result from magnesium’s effects on neuromuscular transmission and cardiac muscle function.

Monitoring for bradycardia is critical because it can indicate that the magnesium level in the patient's body may be too high, leading to toxic effects. Symptoms of bradycardia may not always be apparent, hence the importance of continuous monitoring of the patient’s heart rate and rhythm.

In contrast, while hypoglycemia can occur in various clinical scenarios, it is not a direct complication of magnesium administration. Hyperactivity is not expected in patients receiving magnesium sulfate, as it typically promotes sedation rather than stimulation. Increased blood pressure is also not typically associated with magnesium sulfate, as magnesium generally acts as a vasodilator, which would likely lead to lower blood pressure. Thus, focusing on bradycardia as a critical complication aligns with the pharmacological effects and risks associated with magnesium sulfate therapy.