Breast milk, excretion into

In a review of data on occupational chemicals that may contaminate breast milk (Byczkowski et al. 1994), it is stated that lead may be excreted in milk in amounts lethal to the infant and that the metal may be mobilized from bone stores to milk during the lactation period. Even when the concentration of lead in mother s milk is low, the absorption of metals into the systemic circulation of infants is generally high when they are on a milk diet. To better understand the sensitivity of the nursing infant to chemicals, epidemiological studies, chemical monitoring, and model development and application are needed. 

No studies evaluating the excretion of rifaximin into breast milk and its bioavailability to the infant have been performed. However, due to its very limited, if any, absorption from the GI tract and its physicochemical characteristics any milk excretion of the drug is unlikely... 

Ito S, Lee A Drug excretion into breast milk -Overview. Adv Drug Deliv Rev 2003 55 617-627. 

Breast milk During lactation human mammary tissue expresses the sodium iodide symporter [260], and thus significant transfer of perchlorate into human milk is likely. The presence of micrograms per liter concentrations of perchlorate in milk collected fi om US women [233] confirms lactation as a relevant perchlorate excretion path. If lactating women are secreting perchlorate in milk, then urine-based estimates of total perchlorate exposure for these individuals are likely to be lower than actual [242]. 

Lactation Vitamin B-12 is excreted into breast milk. 

Lactation It is not known whether lepirudin is excreted in breast milk. Because of the potential for serious adverse reactions in nursing infants, decide whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. 

Lactation Quinidine is excreted into breast milk with a milkiserum ratio of approximately 0.71. The American Academy of Pediatrics considers quinidine to be compatible with breast-feeding. 

Lactation Meprobamate is excreted into breast milk at concentrations 2 to 4 times that of maternal plasma. 

Pregnancy Category D- amitriptyline, imipramine, nortriptyline Category C -amoxapine, clomipramine, desipramine, doxepin, protriptyline, trimipramine). Lactation These agents are excreted into breast milk in low concentrations. 

Lactation It is unknown whether or not duloxetine and/or its metabolites are excreted into human milk. Breast-feeding while taking duloxetine is not recommended. 

Lactation Topiramate is excreted in the milk of lactating rats. Limited observations in patients suggest an extensive secretion of topiramate into breast milk. Weigh the potential benefit to the mother against the potential risk to the infant. 

Lactation It is not known whether tizanidine is excreted in human milk although, as a lipid-soluble drug, it might be expected to pass into breast milk. 

Lactation Metoclopramide is excreted into breast milk and may concentrate at about twice the plasma level at 2 hours postdose. There appears to be no risk to the nursing infant with maternal doses less than or equal to 45 mg/day. 

B. Lipid-soluble molecules are more likely to be excreted in breast milk because it is primarily a passive diffusion process. A, C, and D are not correct because they are opposite of the typical characteristics of drugs excreted into breast milk. 

POlOO Faber, P., and A. Strenge-Hesse. Reh evance of rhein excretion into breast milk. Pharmacology 1988 l(Suppl 36) 212-220. 

It is readily absorbed from the GI tract, 99% bound to plasma proteins, distributed into synovial fluid, the central nervous system, placenta and breast milk. It is metabolised in the liver to glucuronide conjugates, excretion of metabolites is predominantly in the urine with some amount appearing in the faeces. 

Tranexamic acid is absorbed from the GIT with peak plasma concentration at about three hours. Bioavailability is about 30 to 50 percent. It is widely distributed throughout the body and has very low protein binding. It diffuses across the placenta and is distributed into breast milk. It has a plasma half life of about two hours. It is excreted in the urine mainly as unchanged drug. 

Despite the fact that most drugs are excreted into breast milk in amounts too small to adversely affect neonatal health, thousands of women taking medications do not breast-feed because of misperception of risk. Unfortunately, physicians contribute heavily to this bias. It is important to remember that formula feeding is associated with higher morbidity and mortality in all socioeconomic groups. 

Spiramycin is incompletely absorbed from the gastrointestinal tract, but widely distributed in tissues. After absorption, some portion of the drug is desmy-carosylated into neospiramycin by gastric acid neospiramycin does not differ from the parent drug in the antibacterial activity (109). Spiramycin is metabolized in the liver to active metabolites and excreted in bile but also in urine. It is found in breast milk. In raw milk, the neospiramycin level was 6-7% of the spiramycin content (110). 

Excretion into breast milk can be a very important route for certain types of foreign compounds, especially lipid-soluble substances, because of the high lipid content in milk. Clearly, newborn animals will be specifically at risk from toxic compounds excreted into milk. For example, nursing mothers exposed to DDT secrete it into their milk, and the infant may receive a greater dose, on a body-weight basis, than the mother. Also, because the pH of milk (6.5) is lower than the plasma, basic compounds may be concentrated in the fluid. 

In addition to teratogenicity, mercury has been associated with decreased reproductive performance in quail (123) and lead with neuro-pathological changes in the suckling rat (124). Both inorganic and organic mercury are excreted into the milk with equal ease (121). Fluoride is known to be excreted by the lactating breast as well (78). 

How breast-milk content changes over the course of the lactational period can affect excretion of toxicants into breast milk. 

The manufacturers of zaleplon advise that it should not be given to breastfeeding mothers since, although only a small amount is excreted into breast milk, the effect on the nursing infant is not known. Zaleplon was... 

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