DSSSB 13 August 2024
Pharmacology
Easy
Which of the following medications DOES NOT cross the placenta?
Appeared in: DSSSB 13 August 2024
Explanation
- Heparin is a large-molecule anticoagulant with a high molecular weight and a strong negative charge.
- These properties make it highly water-soluble (polar) and unable to diffuse across the lipid-based cell membranes of the placental barrier.
- Because it does not enter the fetal circulation, it does not have a direct pharmacological effect on the fetus.
- This safety profile makes Heparin the preferred anticoagulant for use during pregnancy when therapy is required.
Why Other Options Were Wrong
- Option B: Morphine is a lipid-soluble opioid with a low molecular weight, which allows it to readily cross the placenta and affect the fetus.
- Option C: Warfarin is a small, lipid-soluble molecule that easily crosses the placenta. It is a known teratogen and is contraindicated during pregnancy.
- Option D: Naloxone is a small, lipophilic opioid antagonist that crosses the placenta. It is used to reverse the effects of opioids in the neonate.
Related Visual
Clinical Relevance
- Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Placental drug transfer and the safety of anticoagulants during pregnancy as background academic context rather than a clinical decision trigger.
- Understanding which drugs cross the placenta is fundamental to safe medication administration during pregnancy. The choice between Heparin and Warfarin is a classic example of this principle in clinical practice.
- Nurses play a crucial role in educating pregnant patients about the risks associated with certain medications (like Warfarin) and the importance of adhering to safer prescribed alternatives (like Heparin).
- A pregnant patient requiring anticoagulation presents a significant nursing challenge, involving careful monitoring, patient education, and coordination between obstetric and cardiology/hematology teams.
How to Approach the Question
- First, identify the keyword 'DOES NOT'. This indicates you are looking for the exception among the options.
- The core concept is placental drug transfer. Recall the main factors that determine if a drug crosses the placenta: molecular size (small crosses easily), lipid solubility (lipophilic crosses easily), and ionization (non-ionized crosses easily).
- Evaluate each option against these principles.
- Heparin is a well-known large, polar molecule. These characteristics prevent it from crossing the placenta.
- Warfarin, Morphine, and Naloxone are all smaller, more lipid-soluble molecules known to cross the placenta and have effects on the fetus.
- Based on this analysis, Heparin is the only drug listed that does not cross the placental barrier.
Concept Tested & Keywords
- Concept Tested: Placental drug transfer and the safety of anticoagulants during pregnancy.
- Stem keywords: medications, cross the placenta
- Lead-in keywords: DOES NOT
- Negative lead-in flag: The question asks to identify the medication that DOES NOT cross the placenta, requiring you to find the exception among the given options.
Question ID
QbGFretkQLltqVSGXAE3bI
Reference Book
E6 Pharmacology Nurses Shanbhag 3e p. 226-228
E6 Midwifery Obstetrics and Gynecology Nursing Sandeep Kaur p. 46-54
Practise the full DSSSB 13 August 2024
Attempt every question from this paper in a timed mock, then review the full solution for each one.
More Pharmacotherapeutics in Obstetrics Questions
- 22-year-old Megha comes to the doctor because of a missed menstrual period. She has hypothyroidism for which she takes thyroxine; she has an artifici…
- Paracervical block is associated with the danger of?
- Injection Methergine is given to a patient to treat PPH. Which nursing intervention is appropriate for this patient?
- After an epidural block is given to a pregnant mother, the nurse should check for?
- Which injection and dose are given during the active management of the 3rd stage of labor?
- A nurse is administering carboprost to a patient with postpartum hemorrhage (PPH). What is the primary action of carboprost in managing PPH?
- A client is given oxytocin for induction of labor. The side effect of oxytocin is?
- What is the dose of Oxytocin in PPH?
- What is total dose of tab. misoprostol given for prevention of PPH?
- All of the following are teratogens that cause birth defects, except one.
More DSSSB 13 August 2024 Questions
- Which of the following is NOT a component of mental status examination?
- Which therapy is being shown in the given image?
- Which of the following correctly describes esotropia?
- The tablet Arkaminis used in the management of:
- A patient was brought to the emergency department and a blood sample was sent for serum electrolyte level. The report shows that the serum potassium…
- The concept of therapeutic community was first developed by:
- The superego functions based on:
- Reed-Sternberg cells are distinctive, giant cells have light microscopy in biopsies from individuals with the following diseases?
- Which of the following intakes is usually associated with "Flashback phenomenon"?
- Which of the following drugs is commonly used to treat vertigo?