A primigrаvidа аt 37 weeks’ gestatiоn is admitted fоr evaluatiоn of elevated blood pressure. Assessment findings include BP 154/96 mm Hg on two occasions 4 hours apart, 2+ proteinuria, and a mild headache relieved with acetaminophen. The client denies visual disturbances, epigastric pain, and shortness of breath. Fetal status is reassuring. Which prescription should the nurse anticipate?