Which drugs are more likely to pass into breast milk?

Understanding Drug Transfer into Breast Milk
The transfer of drugs into breast milk is a complex process influenced by various pharmacokinetic factors. While many commonly used medications are considered safe for breastfeeding mothers and their infants, understanding which drugs are more likely to pass into breast milk is crucial for new mothers and healthcare providers.
Key Factors Influencing Drug Transfer
1. Molecular Weight: One of the primary determinants of whether a drug will enter breast milk is its molecular weight. Drugs with a smaller molecular weight, typically less than 200 Daltons, are more likely to pass into breast milk. Conversely, larger molecules tend to have reduced transfer rates.
2. Protein Binding: The degree to which a drug binds to plasma proteins also plays a significant role. Drugs that are less protein-bound are more likely to be excreted into breast milk. This is because only the unbound (free) drug can cross biological membranes, including those of the mammary glands.
3. Lipid Solubility: Lipophilic (fat-soluble) drugs are more likely to be transferred into breast milk compared to hydrophilic (water-soluble) drugs. This is due to the fatty composition of breast milk, which can facilitate the passage of lipid-soluble substances.
4. Ionization: The ionization state of a drug at physiological pH can affect its ability to cross into breast milk. Non-ionized drugs are more likely to diffuse across cell membranes, including those in the mammary glands.
Common Drugs and Their Likelihood of Transfer
While most medications are excreted into breast milk to some extent, the actual amount that reaches the infant is often quite low—typically less than 1% of the maternal dose. However, certain drugs have been studied more extensively regarding their safety during breastfeeding:
– Sertraline (Zoloft): This antidepressant is often recommended for breastfeeding mothers due to its minimal levels found in nursing infants.
– Fluoxetine (Prozac): Similar to sertraline, fluoxetine has been well-studied, and its use during breastfeeding is generally considered safe.
– Cannabinoids: Research indicates that THC, the active component in marijuana, can pass into breast milk, potentially affecting infant development.
Recommendations for Breastfeeding Mothers
Healthcare professionals often advise breastfeeding mothers to be cautious with drug use. Recommendations include:
– Timing Medication: If a drug must be taken, it is advisable to do so immediately after breastfeeding or just before the infant’s longest sleep period to minimize exposure.
– Avoiding Certain Substances: Mothers are generally advised to avoid smoking and limit caffeine intake, as these substances can also pass into breast milk.
In conclusion, while many medications are safe for breastfeeding mothers, understanding the factors that influence drug transfer into breast milk is essential. By considering molecular weight, protein binding, lipid solubility, and ionization, mothers can make informed decisions about their medication use while ensuring the safety of their infants.

What passes through breast milk?

Foods and drinks to avoid while breastfeeding
Caffeine passes into breastmilk, so large amounts of tea, coffee and cola drinks are best avoided. Drinking small amounts of drinks with caffeine (3 or less drinks a day) should not be a problem. Alcohol also passes into breastmilk and can affect your baby.

Which drugs are affected by milk?

Common dairy product interactions include certain antibiotics, such as tetracyclines and fluoroquinolones, osteoporosis medications, and iron supplements. Levothyroxine (Synthroid, Unithroid), lithium (Lithobid), and HIV medications also interact with dairy products.

Which of the following allows drugs to enter breast milk more easily from maternal plasma?

Medications normally pass from maternal plasma into the lactocytes, but they must pass through both bilayer lipid membranes of the lactocytes to reach the milk. During the first three days post-partum, however, tight junctions between lactocytes can be open and permit enhanced drug transfer into the milk.

Which drug is usually avoided with breastfeeding?

ANSWER: Only a few drugs pose a clinically significant risk to breastfed babies. In general, antineoplastics, drugs of abuse, some anticonvulsants, ergot alkaloids, and radiopharmaceuticals should not be taken, and levels of amiodarone, cyclosporine, and lithium should be monitored.

What drugs can be passed through breast milk?

Most drug molecules, including alcohol, nicotine and caffeine, are small enough to enter milk. Exceptions are drugs with high molecular weights such as heparins and insulin.

What passes through breast milk to a baby?

Foods and drinks to avoid while breastfeeding
Caffeine passes into breastmilk, so large amounts of tea, coffee and cola drinks are best avoided. Drinking small amounts of drinks with caffeine (3 or less drinks a day) should not be a problem. Alcohol also passes into breastmilk and can affect your baby.

What can pass to baby through breast milk?

Small amounts of any medicine you take may pass through your breast milk to your baby. Generally, the amounts are very low and very few medicines are unsafe while you’re breastfeeding.

Which type of medication readily enters breast milk?

Medications with molecular weights less than 300 are considered smaller and will tend to penetrate to milk in higher concentrations than those with higher molecular weights. An example of a low molecular weight drug is ethanol (Alcohol).

What substances can pass through breast milk?

A woman’s lifestyle may affect her breast milk, and have an impact on the baby. During breastfeeding, it is important for a woman not to consume alcohol, smoke, or take drugs. These substances are known to pass through the breast milk.

What happens if you breastfeed with drugs in your system?

There is still a lot we don’t know about the effects of drugs on your baby when you are breastfeeding but it’s thought that, even at low levels, taking drugs is likely to: make your baby drowsy, feed poorly and have disturbed sleep patterns and poor weight gain. cause behavioural problems.