Final answer:
Magnesium sulfate used in the treatment of preeclampsia acts as an anticonvulsant, aiming to prevent seizures associated with this condition.
Step-by-step explanation:
A woman with preeclampsia being treated with bed rest and intravenous magnesium sulfate is receiving a medication commonly classified as an anticonvulsant. Magnesium sulfate is utilized in this context to help prevent seizures, which is a potential complication of preeclampsia. Although magnesium does have effects on blood pressure and may have some diuretic properties, in the setting of preeclampsia, its role as an anticonvulsant is paramount. It is not a tocolytic, antihypertensive in the conventional sense, nor a diuretic focused on treating hypertension by working on the loop of Henle. Instead, its primary use in preeclampsia pertains to seizure prevention and controlling convulsive episodes.