11.5 Vitamin K, Eye Prophylaxis, Immunization & Routine Neonatal Medications
Key Takeaways
- Every newborn is functionally vitamin K deficient because vitamin K crosses the placenta poorly, the gut is sterile at birth, breast milk is low in vitamin K, and the immature liver carboxylates factors II, VII, IX, and X inefficiently — so prophylaxis is a single 1 mg intramuscular injection into the vastus lateralis within 6 hours of birth for infants over 1,500 g, and 0.3 to 0.5 mg/kg for infants weighing 1,500 g or less.
- Late vitamin K deficiency bleeding occurs from 1 week to 6 months with a peak at 2 to 8 weeks, occurs almost exclusively in unprophylaxed exclusively breastfed infants, and presents as intracranial hemorrhage in 30 to 60% of cases, which is why oral regimens are considered inferior.
- Erythromycin ophthalmic ointment prevents gonococcal ophthalmia but not chlamydial conjunctivitis; silver nitrate is no longer used because it caused chemical conjunctivitis.
- Preterm infants are immunized by chronological age at full dose and vaccines are never deferred to corrected age; the sole routine exception is the hepatitis B birth dose in an infant under 2,000 g born to an HBsAg-negative mother, which is delayed to 1 month or discharge.
- Oral sucrose 24% works only because its analgesic effect is taste-mediated, so it must reach the anterior tongue about 2 minutes before a painful procedure and is useless when instilled through a gastric tube.
Last updated: August 2026
11.5 Vitamin K, Eye Prophylaxis, Immunization & Routine Neonatal Medications
Clinical Pearl & Core Takeaway: The NCC blueprint's pharmacology heading opens its list of common drugs used in neonates with Vitamin K, then eye prophylaxis, vaccines, immunologic agents, diuretics, bronchodilators, and supplements. These are the medications a Level I/II nurse gives on every shift, to every baby — and precisely because they are routine, they are where refusal conversations, dosing errors, and missed windows actually happen.
1. Vitamin K Prophylaxis and Vitamin K Deficiency Bleeding
Why every newborn needs it
Vitamin K is the cofactor for hepatic gamma-carboxylation of clotting factors II, VII, IX, and X plus proteins C and S. Every newborn is functionally vitamin K deficient at birth for four converging reasons:
- Vitamin K crosses the placenta poorly, so fetal stores are minimal.
- The gut is sterile at birth, so there is no bacterial synthesis of vitamin K2.
- Breast milk is low in vitamin K (formula is fortified — which is why late VKDB is overwhelmingly a disease of exclusively breastfed infants).
- The immature liver produces the clotting factors inefficiently.
The dose
- Infants weighing > 1,500 g: a single 1 mg intramuscular dose within 6 hours of birth, into the vastus lateralis.
- Infants weighing ≤ 1,500 g: 0.3 to 0.5 mg/kg as a single intramuscular dose.
The three presentations of VKDB
| Type | Timing | Typical Setting | Presentation |
|---|---|---|---|
| Early | < 24 hours | Maternal medications that impair vitamin K metabolism — anticonvulsants (phenytoin, phenobarbital, carbamazepine), rifampin and other antituberculars, warfarin, and some antibiotics | Cephalohematoma, intracranial, intra-abdominal, and gastrointestinal bleeding |
| Classic | Day 2 to day 7 | Most cases idiopathic; inadequate intake | Gastrointestinal bleeding, bleeding from the umbilical stump, circumcision site, or puncture sites; bruising |
| Late | 1 week to 6 months, peaking at 2 to 8 weeks | Exclusively breastfed infants who did not receive prophylaxis; also cholestasis and malabsorption | Intracranial hemorrhage in 30% to 60% of cases — this is the type that kills and disables |
Handling refusal
Parental declination is rising, and with it the incidence of late VKDB. Oral regimens exist internationally but are less effective, particularly against late VKDB, and require multiple doses with poor adherence. When parents decline:
- Explain concretely: late VKDB has no warning signs, and roughly half of cases present as bleeding into the brain.
- Distinguish clearly for them that this is not a vaccine and contains no live or infectious material.
- Document the discussion, the education provided, and the decision.
- Ensure the declination is communicated to the primary care provider and clearly flagged in the record, because any subsequent bleeding, lethargy, pallor, or seizure in that infant must be treated as VKDB until proven otherwise.
- Circumcision should not proceed without prophylaxis.
2. Ocular Prophylaxis
- Erythromycin 0.5% ophthalmic ointment: a 1 cm ribbon into each lower conjunctival sac, applied within about the first hour of life. Administration may be briefly delayed to support initial bonding and breastfeeding, but should not be omitted.
- Technique: apply from the inner canthus outward, do not rinse it away, and do not touch the tube tip to the eye. Some transient chemical irritation is expected.
- Silver nitrate is no longer used in the United States because it produced a marked chemical conjunctivitis.
- The critical limitation, repeated because it is heavily tested: prophylaxis prevents gonococcal ophthalmia but NOT chlamydial conjunctivitis.
- Prophylaxis is legally mandated in most states, which is why refusal requires a documented conversation and, in many jurisdictions, specific paperwork.
3. Immunization and Immunologic Agents
Hepatitis B vaccine — the birth dose
| Maternal HBsAg Status | Action |
|---|---|
| Negative | Hepatitis B vaccine within 24 hours for medically stable infants weighing ≥ 2,000 g. For infants < 2,000 g, delay the dose to 1 month of age or hospital discharge, because the immune response at very low weight is poor |
| Positive | Vaccine AND hepatitis B immune globulin (HBIG) within 12 hours, at two separate injection sites, regardless of birth weight. For infants < 2,000 g the birth dose does not count toward the series |
| Unknown | Vaccine within 12 hours; test the mother urgently and add HBIG if positive |
The rule that catches people out: preterm infants are immunized by CHRONOLOGICAL age
A 26-week infant who is 2 months old receives the full standard 2-month vaccine series at full dose, even though corrected age is still well below term. Vaccines are never deferred to corrected age and doses are never reduced. The only routine exception is the hepatitis B birth dose in an infant under 2,000 g born to an HBsAg-negative mother. Under-immunization of former preterm infants is a real and preventable harm, because these are exactly the infants for whom pertussis and pneumococcal disease are most dangerous.
RSV immunoprophylaxis
- Nirsevimab, a long-acting monoclonal antibody, is given as a single intramuscular dose to infants under 8 months born during or entering their first RSV season — typically 50 mg for infants under 5 kg and 100 mg for infants 5 kg and over.
- It is not indicated when the mother received the maternal RSVpreF vaccine at 32 to 36 weeks at least 14 days before delivery and the infant is otherwise healthy; it is indicated when maternal vaccination did not occur, is unknown, or occurred within 14 days of birth.
- Palivizumab remains an option in some settings for high-risk infants and requires monthly dosing throughout the season — a critical parent-teaching point, because a single dose confers no season-long protection.
Other immunologic agents
- Hepatitis B immune globulin (HBIG) — as above.
- Varicella-zoster immune globulin (VariZIG) — for infants whose mothers develop varicella from 5 days before to 2 days after delivery.
- Intravenous immune globulin (IVIG) — used in severe isoimmune hemolytic disease to blunt hemolysis and reduce the need for exchange transfusion.
4. Supplements
| Supplement | Who and When | Notes |
|---|---|---|
| Vitamin D | 400 IU daily for all breastfed and partially breastfed infants, beginning in the first days of life; formula-fed infants taking less than about 1 litre daily also need it | Human milk does not contain adequate vitamin D regardless of maternal intake |
| Iron | Preterm infants: 2 to 4 mg/kg/day, typically begun at 2 to 4 weeks of age and continued through the first year. Exclusively breastfed term infants: about 1 mg/kg/day from 4 months until iron-rich complementary foods are established | Preterm infants miss the third-trimester iron accretion. Do not start iron before the physiologic reticulocyte response is under way |
| Medium-chain triglycerides (MCT) | Added for infants with fat malabsorption, cholestasis, chylothorax, or short gut | MCT are absorbed directly into the portal circulation and do not require bile salts or lymphatic transport |
| Human milk fortifier / multivitamins | Preterm infants on human milk | Covered in detail with nutrition |
| Probiotics | Not routinely recommended | Although meta-analyses show reduced necrotizing enterocolitis, the AAP has not endorsed routine use in preterm infants, citing the absence of an FDA-regulated pharmaceutical-grade product, inconsistent strains and viability across products, and reports of invasive infection with the administered organism, including a fatal case that prompted an FDA safety communication. If a unit uses them, it must be under a defined protocol with a known product and strain |
5. Diuretics, Bronchodilators and Other Common Agents
| Drug Class | Agent & Typical Use | Key Nursing Considerations |
|---|---|---|
| Loop diuretic | Furosemide ~1 mg/kg, for fluid overload and symptomatic patent ductus arteriosus or chronic lung disease | Ototoxicity is synergistic with aminoglycosides — never give with gentamicin without discussion. Causes hypokalemia, hyponatremia, hypochloremic metabolic alkalosis, and hypercalciuria leading to nephrocalcinosis with chronic use. Monitor electrolytes and urine output |
| Thiazide + potassium-sparing | Chlorothiazide with spironolactone, for chronic lung disease | Gentler and preferred for long-term use; still monitor electrolytes |
| Bronchodilator | Albuterol by nebulizer, occasionally in established bronchopulmonary dysplasia | Benefit in neonates is limited and transient; watch for tachycardia and tremor. Not a treatment for RDS or TTN |
| Antifungal | Nystatin oral suspension for thrush; topical nystatin for candidal diaper dermatitis | Swab all oral surfaces after feeds and let it remain in contact; treat the mother's nipples concurrently in a breastfeeding dyad or the pair will reinfect each other |
| Non-pharmacologic analgesic | 24% oral sucrose, 0.5 to 2 mL onto the anterior tongue about 2 minutes before a painful procedure, ideally with a pacifier | The analgesic effect is mediated by taste-triggered endogenous opioid release, so it must reach the tongue, not the stomach — never give it through a gastric tube |
| Naloxone | No longer recommended in the delivery room | NRP removed it from neonatal resuscitation. It can precipitate seizures in an infant of an opioid-dependent mother. Respiratory depression is managed with ventilation |
6. Safe Administration of Routine Medications
Routine does not mean low-risk. Three habits prevent most of the harm:
- Independent double-check every parenteral dose, including vitamin K. The dose is 1 mg — not 1 mL, and not 0.1 mg. A vitamin K wrong-dose event is a documented sentinel event.
- Confirm the injection site. Neonatal intramuscular injections go into the vastus lateralis, never the dorsogluteal site, because the gluteal muscle is undeveloped and the sciatic nerve is close to the surface.
- Verify the window. Vitamin K within 6 hours; eye prophylaxis within the first hour; hepatitis B vaccine and HBIG within 12 hours when the mother is HBsAg-positive. Each of these has a defined deadline, and a missed deadline is a reportable variance — not a rounding error.
Loading diagram...
Test Your Knowledge
Parents of a healthy term infant decline the intramuscular vitamin K injection, stating they wish to avoid unnecessary vaccines. Which combination of teaching points and nursing actions is most appropriate?
A
B
C
D
Test Your Knowledge
A former 27-week infant is now 8 weeks old (chronological age) with a corrected gestational age of 35 weeks, is clinically stable in the special care nursery, and is due for the 2-month immunization series. How should the nurse proceed?
A
B
C
D
Test Your Knowledge
A 32-week infant with evolving chronic lung disease is receiving gentamicin for a suspected late-onset infection. The team is considering adding furosemide for fluid overload. What is the most important nursing concern to raise?
A
B
C
D