Drug Safety in Lactation (Rowe 2) Flashcards
What do you need to know about drugs getting into breastmilk (8)?
○ Molecular weight
○ Plasma concentration/systemic bioavailability
○ Half life
○ Lipid solubility
○ Ionization
○ Plasma protein binding
○ Vd
Oral bioavailability
Molecular weight and bf?
greater than 800 daltons doesn’t enter milk well
less than 300 daltons enters milk easily
Ionization w bf?
pKa greater than 7.2 can get trapped
Vd and bf?
Greater than 1 L/kg lower levels in milk
Oral bioavailabilty and bf?
If drug becomes inactive through oral consumption it won’t effect nb
What is relative infant dose?
Daily infant dose via milk divided by lactating parent dose. Need to know parent weight or use 70 kg, and daily milk intake (usually 150 ml/kg/day)
If it is less than 10%, generally we concider it safe. HOWEVER sometimes there are exceptions
Specific drugs to avoid bf?
- Elicit drugs
- Ergot alkaloids
- Anti cancer drugs
- Radioactive drugs
- Alchohol
- Narcotics and sedatives
○ Esp. active metabolites and CYP2D6 metabolism, long half lives, and regular use.
○ EG Codeine and diazepam - Water soluable beta blockers
- Lithium
- Hemolytic agents eg nitrofurantoin, sulfamethoxazole/trimethoprim
What are galactagogues?
Galactagogues increase milk supply (blocks dopamine to increase prolactin in the plasma)
What are side effects of Domperidone?
insomnia, dizziness, lethargy, irritability, headache, dry mouth, prolonged QT interval; We mostly worry about prolonged QT interval - abnormal heart rythmn that can lead to sudden death
What are contraindications to domperidone (4)?
preexisting heart condition
low blood levels of potassium or magnesium
other medications that alter the electrical activity of the heart or prolong QT, (ketaconazole, methadone, SSRIs)
prolactin-releasing tumour
4 useful references to determine the suitability of medications in lactation?
LactMed
Medications and Mothers Milk
Drugs in pregnancy and lactation
OTIS
