Drug use in the neonate

Question 1

What is the most effective reliable method of drug administration to a neonate and why?

Answer 1

Intravenous

• you know exactly how much drug is being absorbed into circulation to have an effect
• removes variables such as vomiting and hepatic first pass effect

Question 2

What factors affect the absorption of a drug given IM to a neonate?

Answer 2

• less muscle mass
• thinner cellular membranes and increased capillary density
• immature circulatory system

Question 3

what other factors affect drug absorption in the neonate, particularly oral?

Answer 3

• immature GI tract - small surface area, altered pH changes ionisation, changes in bile salt pool
• decreased gastric emptying
• less bacterial colonisation of intestines
• vomiting/reflux
• reduced compliance

Question 4

What factors influence drug distribution in the neonate?

Answer 4

• body water:fat percentage (low body fat: high body water)
• protein binding - lower plasma proteins, bilirubin competes for binding sites on proteins
• immature blood-brain barrier

Question 5

What factors influence drug metabolism in the neonate?

Answer 5

• hepatic blood flow increases with age

- immature liver enzymes has variable effect

Question 6

What factors influence drug elimination in the neonate?

Answer 6

• immature renal function - lower GFR, generally drugs excreted by liver have prolonged elimination half-life
• gestational age
• adequate fluid intake

Question 7

Why are antimicrobials commonly used in neonates?

Answer 7

• immature immune systems

- excessive use has contributed to development of antibiotic resistance - consider judiciousness and safety

Question 8

What are the risks associated with antimicrobial use in neonates?

Answer 8

• elimination of protective normal flora

- unknown long term impacts

Question 9

Why are diuretic drugs used in neonates?

Answer 9

• hypertension
• congestive heart failure
• renal dysfunction

Question 10

What are 2 risks of IV administration in neonates?

Answer 10

• potential for overdosage due to incorrect calculations

- potential for infection through IV access site

Question 11

Why do neonates tend to be at higher risk of dosage calculation errors?

Answer 11

• complex factors influence pharmacokinetics
• individualised dosing calculations
• some drugs need to be diluted
• slow IV rates

Question 12

What methods are used to calculate drug dosages in the neonate

Answer 12

• weight per kilogram

- body surface area

Question 13

What is the formula for calculating neonatal drug dosages according to weight per kilogram?

Answer 13

dose to be given = recommended dose (mg/kg) x weight (kg)

Question 14

What is the definition of a neonate?

Answer 14

A baby within it’s first 28 days of life.

Question 15

What strategies may decrease the risk of drug errors for neonates?

Answer 15

• double checking calculations
• accessible examples of calculations
• using standardised drug preparations and dosing
• asking questions about whether a drug should be administered
• volume should feel appropriate

Question 16

What is the trade name for benzylpenicillin?

Answer 16

BenPen

Question 17

What is the usual indication for benzylpenicillin in neonates?

Answer 17

antibiotic for treatment of susceptible organisms (e.g GBS, congenital syphilis)

Question 18

What is the stock strength and usual dosage of benzylpenicillin for neonates?

Answer 18

600mg vial (as powder for reconstitution with water for injection)
depending on and and indication around 50mg/kg/6-12 hrly
as IM or slow IV over 3-5 minutes

Question 19

What adverse effects are associated with benzylpenicillin use in neonates?

Answer 19

• hypersensitiviy
• rash
• diarrhoea
• seizures at high doses
• haemolytic anaemia

Question 20

What is the usual indication for gentamicin in neonates?

Answer 20

aminoglycoside antibiotic for treatment of infections caused by susceptible organisms e.g. e.coli, pseudomonas, klebsiella

Question 21

What is the stock strength and usual dosage of gentamicin for neonates?

Answer 21

80mg/2ml ampoules
IV is given diluted as a 10mg/mL solution over 10 minutes
IM is used undiluted
dose depends on gestation, given 24-48 hourly

Question 22

What precautions/side effects are associated with the use of gentamicin in neonates?

Answer 22

• high risk medication
• can cause renal impairment and deafness
• usually used with therapeutic drug monitoring loking at area under curve, peak and trough levels of drug over time

Question 23

What is the trade name of caffeine citrate?

Answer 23

Cafnea

Question 24

What is the usual indication for caffeine citrate in neonates?

Answer 24

• stimulates inspiratory drive and increases sensitive of medullary centre to CO2
• used for prevention or treatment of apnoea associated with prematurity, infection or anaesthesia and to aid extubation of ventilated babies

Question 25

What is the stock strength and usual dosage of caffeine citrate for neonates?

Answer 25

available as oral solution 10mg/ml or 50mg/5 ml ampoule for IV infusions loading dose is 20mg/kg with maintenance dose of 5-7.5mg/kg/day at least 24 hours later (need to dilute maintenance dose) - give oral dose with feeds - routine monitoring of drug levels not required

Question 26

What adverse effects are associated with caffeine citrate?

Answer 26

- nausea/vomiting - gastric irritation - agitation - tachycardia - diuresis - overdose - arrhythmias and seizures

Question 27

What is the trade name of Vitamin K (phytomenadione)?

Answer 27

Konakion

Question 28

What is the usual indication for phytomenadione in neonates?

Answer 28

- prophylaxis for vitamin K deficiency bleeding in the newborn - no colonisation of gut with bacteria that produce vitamin k, poorly transferred across placenta and low concentrations in breastmilk, vital for clotting pathways

Question 29

When should phytomenadione be given to neonates?

Answer 29

- with maternal consent within 24 hours of birth

Question 30

What is the usual stock strength, route and dose of phytomenadione in neonates?

Answer 30

2mg/0.2mL ampoules Can be given IM (preferred) or orally in 3 doses usual dose is 1mg (0.1ml) IM at birth if orally 2mg(0.2ml) at birth, 3-5 days and 4 weeks, last dose omitted if formula fed

Question 31

What adverse effects are associated with phytomenadione?

Answer 31

- very few - facial flushing, sweating and unusual taste - rarely anaphylaxis or injection site reactions

Question 32

What is the protocol if there is a neonatal drug error or near miss?

Answer 32

- location specific - assess clinical situation - report incident to shift coordinator and medical officer - seek advice from pharmacy - inform patient as appropriate - documentation

Question 33

What is therapeutic drug monitoring?

Answer 33

Therapeutic drug monitoring is the individualisation of dosage by maintaining plasma or blood drug concentrations within a target therapeutic range to maximise therapeutic effects and avoid adverse effects

Question 34

Which neonatal drugs are often used with TDM?

Answer 34

- caffeine citrate - phenobarbitol - phenytoin - gentamicin - vancomycin - digoxin

Question 35

What 7 pieces of information are required to accurately perform TDM?

Answer 35

- Time of sample in relation to last dose - Duration of treatment at the current dose levels - Dosing schedule - Age and gender of patient - Other concurrent drug therapies - Relevant disease states - Reason TDM requested i.e. suspected toxicity or lack of efficacy.

Question 36

What is the trade name of beractant? and what is its usual indication in neonates?

Answer 36

- Survanta | - pulmonary surfactant used for prevention or treatment of respiratory distress syndrome

Question 37

What is the stock strength and usual dose of beractant in neonates?

Answer 37

- 25mg/8mL vial stored in refridgerator, warm to room temp before use - usual dose is 4mL/kg/dose administered through intratracheal tube - up to 4 doses at 6 hourly invervals

Question 38

What adverse effects may be associated with beractant?

Answer 38

- transient bradycardia - oxygen desaturation - ETT reflux - pallor - vasoconstriction - hypo/hypertension - apnoea

Question 39

What is the definition of apnoea in neonates?

Answer 39

- no effective respiratory effort for 20 seconds or shorter if associated with bradycardia

Question 40

What is the usual management for apnoea in neonates?

Answer 40

caffeine citrate

Question 41

Why may sucrose be given to neonates?

Answer 41

- for relief of procedural pain - effect lasts 5-8 minutes - more effective if combined with sucking

Question 42

What is the usual dose for sucrose in the healthy term neonate?

Answer 42

stock strength 33% sucrose solution | 0.2-1mL PO max dose 5ml