Final answer:
A nurse should administer methylergonovine to promote uterine contractions in a patient with a soft uterus and increased lochia, as it effectively enhances uterine muscle tone and contraction. The correct answer is options B.
Step-by-step explanation:
The nurse should plan to administer methylergonovine to promote uterine contractions for a client with a soft uterus and increased lochia. This medication is an ergot alkaloid that directly stimulates the smooth muscle of the uterus, leading to increased tone, rate, and amplitude of rhythmic contractions, thereby controlling bleeding and aiding in the contraction of the uterus postpartum.
A nurse must not administer mag sulfate because it is a tocolytic that relaxes the uterus. Similarly, terbutaline and nifedipine are also tocolytics and should be avoided as they would further inhibit uterine contractions. Instead, the nurse should focus on the administration of medications that enhance contractions, like methylergonovine, or in some cases, oxytocin (pitocin) may be used as it stimulates the uterine contractions through the natural pathway of childbirth. So, The correct answer is options B