Drug Exposure Via Milk Flashcards
Some important drug properties that may determine exposure of drug in breast milk include…
And what increases this likelihood?
Molecular weight - smaller
Protein beinding - low
Vd - small Vd
Lipid solubility - highly lipid soluble
Ionization + drug pKa - unionized, basic drugs
Bioavailability - high
Half-life - longer
Some parent variables that may determine drug exposure in breast milk include…
Milk composition
Concentration of drug - dose, ADME
Drug interactions
Some infant variables that may determine drug exposure in breast milk include…
Milk consumption - frequency of feeding + volume consumed
Age - different ADME (less robust glomerular filtration, hepatic metabolism until 6-12 months)
Regarding drug interactions, we need to be cautious around…
Interactions between medications given to parent and mediations given to infant
Some potential adverse drug effects on infant via milk exposure may include…
Drowsiness, irritability, GI upset, diarrhea/constipation
Allergic sensitization, hemolysis, blood dyscrasias
Safety data is limited for lactation in that…
Lactation is an exclusion criterion for RCT’s (ethicality)
Animal data cannot be fully extrapolated to humans
Default to primarily observational data
Some advantages of collecting safety data for lactation compared to pregnancy is that…
Direct observation is possible - monitor for AE’s
Generally lower exposure via milk than placenta
The milk to plasma (M/P) ratio measures…
The concentration of the drug in the milk, compared to concentration of drug in the plasma
A M/P ratio ____ indicates that the drug concentrates in the milk.
> 1
Does M/P indicated safety of medication?
No - it is only a ratio and also not an absolute amount of drug
Even if M/P is greater than 1… If maternal plasma level is small, then the absolute amount of drug entering milk is small - minimal concentration is unlikely to have effect
The relative infant dose (RID) is a means of…
Estimating infant exposure to drugs used in lactation
RID is calculated via…
Infant dose (mg/kg/day) divided by maternal dose (mg/kg/day) x 100%
The infant dose used to calculated RID is determined by…
Concentration of the drug in the milk, and the volume of milk being consumed by infant divided by weight
Drugs with this RID are likely safe for short term use…
<10% (term infants)
<1% (premature infants)
Generally, slecting medications with lower RID helps maximize safety. Most medications have RID <1%
Infant plasma concentrations to estimate exposure is more accurate because…
It accounts for oral absorption/elimination effects
However limited availability due to poking
Some strategies to limit infant exposure include…
Using drugs only if necessary
Decreasing parenteral systemic exposure
Avoid feeding at times of peak drug concentration + use short-acting if possible
“Pump & Dump”
Using donated milk
Potential drug effects on milk production include…
Decreased production (before breastfeeding is established)
Increased production (exploited therapeutically)
If decreased production with insufficient supply to meet infant’s needs, monitor for cues (urination, BM, weight gain, growth, etc.)
If parents believe they have low milk production, they should ideally…
Be referred to their primary care provider +/- lactation consultant
A galactagogue is a medication/substance that…
Is believed to augment maternal milk production
The most common galactagogues are ____ and they work by…
Metoclopramide
Domperidone
Stimulate prolactin release
Routine use of galactagogues are not recommended due to…
Limited, weak evidence to support efficacy
Potential safety concerns (withdrawal + dopamine like side effects)
Some adverse effects with domperidone include…
Nausea, diarrhea, abdominal cramping
SOB
Headache, dry mouth, dizziness
QT issues
Withdrawal
Some adverse effects with metoclopramide include…
Headache
N/D, gas
Dry mouth
Fatigue
Breast discomfort
Depression
Evidence of herbal products as galactagogues is…
Insufficient to determine safety + efficacy - not recommended
Galactagogues should NOT be considered before…
Support, education, and breastfeeding technique
When selecting drugs for breastfeeding we should consider…
Risks of not breastfeeding/treating condition
Necessity of pharmacotherapy
Availability of published data - effect on infant, milk supply, RID
Infant variables
Drug properties
