Patt -
The drug you'd asked about: Mesalamine, is included in : DRUGS IN PREGNANCY AND
LACTATION, by G.G. Briggs, R.K. Freeman, and S.J. Yaffe, copyright 1994(4th
edition), pages 551-553: "Breast Feeding Summary: Small amounts of mesalamine
are excreted into human milk. A 1990 report described the excretion of
mesalamine and its metabolite, acetyl-5-aminosalicylic acid, into breast milk
(11). The woman was receiving 500 mg three times daily for ulcerative colitis.
In a single plasma and milk sample obtained 5.25 hours after a dose, milk and
plasma levels of mesalamine were 0.11 ug/ml and 0.41 ug/ml, respectively, a
milk:plasma ratio of 0.27. Milk and plasma levels of acetyl-5-aminosalicylic
acid were 12.4 ug/ml and 2.44 ug/ml, respectively, a ratio of 5.1. In another
study, women treated prophylactically with 3g/day of sulfasalazine had milk
levels of mesalamine and acetyl-5-aminosalicylic acid of 0.02 ug/ml and 1.13 -
3.44 ug/ml, respectively (4). No adverse effects on the nursing infants were
mentioned.
Diarrhea in a nursing infant, apparently due to the rectal administration
of mesalamine to the mother, has been reported (12). The mother had relapsing
ulcerative proctitis. Six weeks after childbirth, treatment was begun with
500-mg mesalamine suppositories twice daily. Her exclusively breast-fed infant
developed watery diarrhea 12 hours after the mother's first dose. After 2 days
of therapy, the mother stopped the suppositories and the infant's diarrhea
stopped 10 hours later. Therapy was reinstituted on four occasions with diarrhea
developing each time in the infant 8 - 12 hours after the mother's first dose
and stopping 8 - 12 hours after therapy was halted. Because of the severity of
the mother's disease, breast feeding was discontinued and no further episodes of
diarrhea were observed in the infant.
Because of the adverse effect described above, nursing infants of women
being treated with mesalamine or olsalazine should be closely observed for
changes in stool consistency. The American Academy of Pediatrics classifies
mesalamine (i.e., 5-aminosalicylic acid) as a drug that has produced adverse
effects in a nursing infant and should be used with caution during breastfeeding
(13). "
This is followed by a list of references corresponding to the numbers in parens.
If you want an actual copy of this, e-mail me and I'll send one.
Two additional notes: first, the same authors and book rate the fetal risk
factor as "B" on a scale of A, B, C, D, X, where A means demonstrating no fetal
risk and X means evidence of fetal risk based on human studies or human
experience. Under Fetal Risk Summary is the following statement: "No
fetotoxicity or congenital malformations have been attributed to the use of
mesalamine during pregnancy. A recent review of drug therapy for ulcerative
colitis recommended that women taking mesalamine to maintain remission of the
disease should continue the drug when trying to conceive or when pregnant (5)."
Although there are differences in the pregnant versus lactating woman, I always
want to know why a woman can relatively safely take a drug during her pregnancy
and the same drug is now considered a substantial enough risk to contemplate
discontinuing breastfeeding. Just a thought...
Jeanine Klaus, MS, IBCLC, LLLL
Oakville, Ontario
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