RNC-NIC Pharmacology & Therapeutic Management 5 — Questions and Answers
Question 1: A term neonate is receiving heparin through a PICC line for catheter patency. Which laboratory value most directly reflects heparin anticoagulation effect?
- Prothrombin time (PT)
- Anti-factor Xa level (Correct answer)
- Platelet count
- Fibrinogen level
Correct answer: Anti-factor Xa level
Anti-factor Xa levels are the most reliable measure of heparin anticoagulation in neonates because aPTT is affected by the physiological coagulation differences in newborns.
Question 2: A neonate with persistent hypoglycemia unresponsive to glucose infusion rates >12 mg/kg/min is started on diazoxide. What is the mechanism of action of diazoxide in neonatal hypoglycemia?
- Stimulates pancreatic beta-cell insulin secretion
- Opens ATP-sensitive potassium channels, suppressing insulin release (Correct answer)
- Inhibits glucagon secretion
- Promotes hepatic glycogenolysis
Correct answer: Opens ATP-sensitive potassium channels, suppressing insulin release
Diazoxide opens ATP-sensitive K+ channels on pancreatic beta cells, hyperpolarizing the membrane and inhibiting insulin secretion—useful in hyperinsulinemic hypoglycemia.
Question 3: A preterm neonate develops necrotizing enterocolitis and is placed on bowel rest with IV antibiotics. After 14 days of NPO status, which nutritional supplementation becomes critically important to prevent deficiency?
- Vitamin D supplementation
- Selenium supplementation
- Zinc supplementation
- Trace element and vitamin supplementation via TPN (Correct answer)
Correct answer: Trace element and vitamin supplementation via TPN
Prolonged NPO with TPN requires complete trace elements and vitamins to be added to the TPN solution to prevent deficiency states that would otherwise be supplied by enteral feeds.
Question 4: A neonate with meningitis is receiving ampicillin and cefotaxime. CSF culture returns group B Streptococcus sensitive to penicillin. What is the recommended duration of antibiotic therapy?
- 7 days
- 10 days
- 14 days
- 21 days (Correct answer)
Correct answer: 21 days
GBS meningitis in neonates requires a minimum of 14–21 days of IV penicillin therapy; most guidelines recommend 21 days due to the risk of relapse and neurological sequelae.
Question 5: A nurse is preparing to administer sildenafil to a neonate with PPHN. What is the primary mechanism by which sildenafil improves pulmonary hypertension?
- Blocks endothelin receptors causing vasoconstriction
- Inhibits phosphodiesterase-5, increasing cGMP and promoting vasodilation (Correct answer)
- Stimulates prostacyclin receptors on pulmonary vasculature
- Blocks calcium channels in pulmonary vascular smooth muscle
Correct answer: Inhibits phosphodiesterase-5, increasing cGMP and promoting vasodilation
Sildenafil inhibits PDE-5, the enzyme that degrades cGMP; elevated cGMP causes pulmonary vascular smooth muscle relaxation and reduces pulmonary vascular resistance.
Question 6: A 27-week neonate develops thrombocytopenia after 7 days of heparin-containing TPN. Which condition should the nurse consider and report?
- Dilutional thrombocytopenia from fluid overload
- Heparin-induced thrombocytopenia (HIT) (Correct answer)
- Disseminated intravascular coagulation (DIC)
- Drug-induced bone marrow suppression
Correct answer: Heparin-induced thrombocytopenia (HIT)
Although rare in neonates, HIT can occur with heparin exposure; a ≥50% platelet drop after 5–10 days of heparin therapy should trigger HIT evaluation and heparin discontinuation.
Question 7: Acyclovir is prescribed for a neonate with disseminated herpes simplex virus (HSV) infection. Which laboratory value must be monitored closely during high-dose acyclovir therapy?
- Serum calcium
- Serum creatinine (Correct answer)
- Serum sodium
- Serum bilirubin
Correct answer: Serum creatinine
High-dose acyclovir (60 mg/kg/day) can cause crystal nephropathy and acute kidney injury; serum creatinine must be monitored at least every 48 hours during neonatal HSV treatment.
RNC-NIC Pharmacology & Therapeutic Management 5
A term neonate is receiving heparin through a PICC line for catheter patency.
Which laboratory value most directly reflects heparin anticoagulation effect?