Mothers often anxiously seek advice about whether medications they take might pass into breast milk. Yet they worry about weaning and losing their milk supply, unsure what to do. Now, Mom Says has compiled a list of medications that do pass into breast milk, allowing you to nurse your baby with greater peace of mind.
It is well known that many medications can be excreted through breast milk, and some may cause adverse effects or harm to the baby. Therefore, medication use during lactation and whether breastfeeding can continue during treatment are important considerations. In clinical practice, multiple factors should be weighed to provide proper guidance on medication use for breastfeeding women.
When breastfeeding women take medication, they often focus solely on whether the drug affects milk production, rarely considering its impact on the infant—or simply unaware which drugs pose risks. In reality, many medications can enter the infant's body through breast milk, potentially affecting the nursing baby. Even if the concentration in milk is low, the harm can be significant for the fragile, developing infant.
Factors Influencing Drug Transfer into Breast Milk
1. Pharmacokinetic Characteristics: Due to physiological differences, lactating women exhibit distinct pharmacokinetic profiles. Drugs bound to maternal plasma proteins cannot be transferred into breast milk; only the free form can be transported. The plasma concentration of the free drug depends on the administered dose and its metabolic processes within the body.Drugs with high bioavailability, low protein binding, small apparent volume of distribution, and long half-lives exhibit greater transfer into breast milk. Clinicians should be familiar with the pharmacokinetic properties of these drugs, particularly newly marketed ones, and exercise caution when prescribing them based on comprehensive consideration.Most drugs are weak electrolytes that ionize to varying degrees. Only non-ionized drugs can cross biological membranes. Clinically used drugs are predominantly weak acid or weak base salts. Typically, non-lipophilic drugs face greater difficulty in transferring to breast milk, whereas drugs with high acid dissociation constants exhibit the opposite behavior. These drugs remain poorly ionized in plasma, resulting in minimal lipophilicity changes and facilitating transfer to breast milk.Consequently, weakly basic drugs exhibit higher concentrations in breast milk.
3. Influence of Drug Concentration Gradient Drug transport from maternal blood into breast milk requires crossing the blood-milk barrier. The concentration gradient between blood and milk is the primary factor governing drug transfer. A larger gradient facilitates greater transport. The impact of drugs on infants can be assessed by calculating the concentration ratio between breast milk and maternal plasma.Drugs with low molecular weight, low protein binding, high lipid solubility, and high degree of nonionization readily enter breast milk. Effects of Common Drugs on Newborns 1. Antibiotics and Other Antimicrobials Antibiotic concentrations in breast milk vary significantly. Allergic or toxic reactions are occasionally observed. Repeated low-dose exposure to antibiotics in infants readily promotes the emergence of drug-resistant strains.
Penicillins and cephalosporins may enter breast milk in small amounts, potentially disrupting the infant's normal intestinal flora. Trace amounts of penicillin or ampicillin in breast milk can cause allergic reactions in infants, which may be life-threatening.Tetracyclines may damage infant bones and tooth enamel. Chloramphenicol carries potential risks of bone marrow suppression and gray baby syndrome. Erythromycin concentrations in breast milk can be 4–5 times higher than maternal blood levels during lactation, increasing the risk of cholestatic jaundice in infants.With the exception of those poorly absorbed orally, sulfonamide drugs are excreted in breast milk, often at concentrations exceeding maternal blood levels. This poses particular risks for premature infants, frail infants, those with hyperbilirubinemia, and infants with G-6-PD deficiency.Quinolones may cause hemolytic anemia in infants, while isoniazid can lead to hepatic toxicity. Ketoconazole and fluconazole can be absorbed into breast milk, where concentrations approach those in maternal blood, potentially harming infants. Nursing mothers should exercise caution when using topical formulations containing these drugs.
2. Central Nervous System Depressants Medications like alprazolam, estazolam, and diazepam used to treat anxiety and sleep disorders may cause drowsiness in infants when used long-term by nursing mothers. Withdrawal symptoms may also occur after discontinuation, posing potential adverse effects. Since these drugs can be absorbed into breast milk, breastfeeding should be discontinued during their use.
3. Antipyretic analgesics: A certain proportion of lactating women use analgesics, particularly mild ones. Many compound Chinese herbal formulations for treating colds and flu contain antipyretic analgesic components.Examples include acetaminophen, phenacetin, antipyrine, aspirin, diclofenac, and indomethacin. Aspirin may cause bone marrow suppression in infants, acetaminophen can lead to liver damage in infants, and diclofenac may cause hematuria in infants.Lactating women should exercise caution when using Chinese herbal compound preparations containing the aforementioned Western pharmaceutical ingredients. Carefully read the medication instructions to understand the specific components and their concentrations. Do not fall into the misconception that "Western medicine is toxic while Chinese medicine is harmless." Some addictive analgesics, such as morphine and codeine, achieve high concentrations in breast milk.Infants breastfed by women with opioid addiction may also develop dependence. Newborns are highly sensitive to these drugs and may experience respiratory depression. Therefore, breastfeeding women must absolutely avoid using them.>Factors Influencing Gender Selection 1008511
Zodiac Pairings Prone to Producing Gifted Children 923058
Pre-Delivery Midwifery Techniques 852070
3-6 Years: Optimal Literacy Development Age 813905
Unveiling the Truth Behind Celebrity Miscarriages 766246
>Have You Seen These Handsome Celebrities' Childhood Photos? 695481
7 Signs That May Indicate You're Pregnant 669083
How Painful Is Natural Childbirth? 631522
4 Optimal Times for Sperm and Egg to "Meet" 605394