RNC-NIC Pharmacology & Therapeutic Management 3 — Questions and Answers
Question 1: A 32-week neonate receives their first dose of gentamicin. When should the initial trough level be drawn to guide extended-interval dosing?
- 30 minutes before the second dose (Correct answer)
- Immediately after the first infusion ends
- 12 hours after the first dose
- Just before the third dose
Correct answer: 30 minutes before the second dose
For extended-interval aminoglycoside dosing, a trough level is drawn just before the next scheduled dose to ensure adequate drug clearance and prevent accumulation.
Question 2: Surfactant replacement therapy is ordered for a 26-week neonate with RDS. Which finding indicates the surfactant was effective?
- Increased FiO2 requirement within 30 minutes
- Improvement in lung compliance with decreased ventilator pressures (Correct answer)
- Development of metabolic acidosis
- Increase in peak inspiratory pressure
Correct answer: Improvement in lung compliance with decreased ventilator pressures
Effective surfactant therapy reduces alveolar surface tension, improving lung compliance and allowing ventilator pressure requirements to decrease.
Question 3: Which vitamin K preparation is recommended for prophylaxis against hemorrhagic disease of the newborn?
- Menadione (vitamin K3) oral
- Phytonadione (vitamin K1) IM (Correct answer)
- Menaquinone (vitamin K2) oral
- Phytonadione (vitamin K1) subcutaneous
Correct answer: Phytonadione (vitamin K1) IM
Phytonadione (vitamin K1) 0.5–1 mg IM within 6 hours of birth is the standard prophylaxis for vitamin K deficiency bleeding (VKDB) in all newborns.
Question 4: A neonate with NEC is receiving ampicillin, gentamicin, and metronidazole. What is the primary rationale for including metronidazole in this regimen?
- Coverage of gram-positive organisms
- Coverage of anaerobic bacteria (Correct answer)
- Synergy with ampicillin against Enterococcus
- Prevention of fungal superinfection
Correct answer: Coverage of anaerobic bacteria
Metronidazole provides anaerobic bacterial coverage, which is critical in NEC because intestinal flora including Bacteroides and Clostridium species contribute to the infection.
Question 5: A nurse administers dexamethasone to a ventilator-dependent VLBW neonate for chronic lung disease. Which adverse effect is of greatest long-term concern?
- Transient hyperglycemia
- Gastrointestinal bleeding
- Impaired neurodevelopmental outcomes (Correct answer)
- Fluid retention
Correct answer: Impaired neurodevelopmental outcomes
Postnatal systemic corticosteroids, particularly dexamethasone, are associated with increased risk of cerebral palsy and adverse neurodevelopmental outcomes, limiting their use.
Question 6: A term neonate with seizures unresponsive to phenobarbital is given fosphenytoin. Which cardiac monitor finding requires immediate dose interruption?
- PR interval of 0.16 seconds
- Heart rate of 130 bpm
- QTc interval of 490 ms (Correct answer)
- QRS duration of 80 ms
Correct answer: QTc interval of 490 ms
Fosphenytoin can cause QT prolongation and serious arrhythmias; a QTc >450–500 ms signals cardiac toxicity requiring immediate dose interruption.
Question 7: Prostaglandin E1 (alprostadil) is infusing to maintain ductal patency in a neonate with critical pulmonary stenosis. Which adverse effect is most unique to prostaglandin E1 infusion?
- Bradycardia
- Apnea (Correct answer)
- Hypertension
- Hyperkalemia
Correct answer: Apnea
Apnea is a well-recognized and potentially life-threatening adverse effect specific to PGE1 infusions, occurring in approximately 10–12% of neonates, and requires close respiratory monitoring.
RNC-NIC Pharmacology & Therapeutic Management 3
A 32-week neonate receives their first dose of gentamicin.
When should the initial trough level be drawn to guide extended-interval dosing?