Opioids such as hydromorphone, fentanyl, and meperidine can cause excessive CNS depression in both the mother and newborn.

Opioid antagonists such as naloxone (Narcan) can promptly reverse the CNS depressant effects, especially respiratory depression.

The RN should avoid the use of or use extreme caution in administering naloxone to opioid-dependent patients.

Choice A rationale

The cost of a medication is a logistical consideration, not a scientific or pharmacological basis for its clinical preference during labor. The selection of an analgesic is primarily determined by its therapeutic profile, including efficacy, safety for both mother and fetus, and its mechanism of action, rather than economic factors.

Choice B rationale

The administration route is a clinical characteristic, but it does not explain why these specific drugs are preferred. Butorphanol and nalbuphine are typically administered intravenously or intramuscularly, not orally, to achieve rapid onset and predictable plasma concentrations, which is crucial for managing acute labor pain.

Choice C rationale

These medications, like most opioids, are lipophilic and have low molecular weights, allowing them to readily cross the placental barrier via passive diffusion. This is a significant aspect of their pharmacology. The preference for these specific drugs lies in their partial agonist/antagonist activity, which mitigates some of the risks of fetal respiratory depression.

Choice D rationale

Butorphanol and nalbuphine are synthetic opioid agonist-antagonists. This unique pharmacological profile means they bind to and activate kappa opioid receptors while acting as antagonists or partial agonists at mu opioid receptors. This dual action provides effective pain relief while concurrently limiting the degree of respiratory depression compared to full mu-opioid agonists, making them a safer choice for both mother and fetus during labor. *.

Choice A rationale

The statement, "I am glad they are giving me something to try to stop my labor for now," shows a correct understanding of nifedipine's role as a tocolytic agent. Nifedipine, a calcium channel blocker, works by inhibiting the influx of calcium into uterine muscle cells, which is necessary for contraction. This effectively slows or stops preterm labor, giving time for corticosteroids to work.

Choice B rationale

The statement, "This medication can lower my blood pressure to dangerous levels," shows a correct understanding of a major side effect of nifedipine. As a calcium channel blocker, it causes vasodilation, which can lead to a drop in blood pressure. The patient should be monitored for hypotension and advised to report symptoms like dizziness or lightheadedness.

Choice C rationale

The statement, "I will let you know if I feel dizzy," indicates a correct understanding of a common symptom associated with the hypotensive effect of nifedipine. Dizziness is a direct result of decreased cerebral blood flow due to lower blood pressure. Reporting this symptom allows the nurse to intervene and prevent falls or other complications.

Choice D rationale

The statement, "Nifedipine should help mature my baby's lungs," is incorrect. Nifedipine is a tocolytic used to stop uterine contractions. The medication used to promote fetal lung maturity is a corticosteroid, such as betamethasone. This statement indicates a need for additional teaching to differentiate the purpose of these two classes of medications.