Is Carbamazepine safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Carbamazepine. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
No adverse effects were noted by the mothers in 3 breastfed infants during maternal carbamazepine and phenytoin therapy.[ 5 ] An epileptic woman taking carbamazepine 1 gram and primidone 1 gram daily during pregnancy and postpartum breastfed her infant for 5 weeks and noted no difference in activity in the infant before and after nursing.[ 7 ] A probable case of drug-induced drowsiness occurred in a newborn whose mother was taking primidone, carbamazepine and phenytoin (dosages not stated). At day 30, breastfeeding was discontinued because of the drowsiness that occurred after each feeding and poor weight gain. The same group of researchers found that 15 partially breastfed infants whose mothers were taking various anticonvulsants, including carbamazepine, gained weight at a slower rate during the first 5 days postpartum than did 75 infants of epileptic mothers who bottle fed or control mothers taking no medications.[ 19 ] A 10-week-old breastfed infant whose mother was taking clemastine, phenytoin and carbamazepine was drowsy, refused to feed, was irritable, and had high-pitched crying.[ 20 ] These side effects were possibly caused by clemastine in breastmilk, but carbamazepine could also have contributed. Poor sucking, vomiting and lack of weight gain was reported in a partially breastfed 4-week-old whose mother was taking carbamazepine monotherapy in a dose of 11 mg/kg daily.[ 8 ] Weak sucking occurred in 1 of 15 breastfed infants whose mothers were on carbamazepine monotherapy, but a causal relationship could not be confirmed.[ 9 ] A breastfed infant whose mother was taking primidone 375 mg, phenobarbital 90 mg, and carbamazepine 800 mg daily did well despite a saliva phenobarbital level of 3.4 mg/L. At 7 months of age, after the mother abruptly stop nursing, the infant had a number of "startle reactions" and infantile seizures occurred which were confirmed by an abnormal electroencephalogram. Continued phenobarbital administration to the infant for 15 months co
Effects on milk supply
Relevant published information was not found as of the revision date. One woman on long-term carbamazepine therapy had slight galactorrhea 3.5 years after delivery, although her serum prolactin was normal.[ 9 ] The prolactin level in a mother with established lactation may not affect her ability to breastfeed.
Levels in milk
In published reports of anticonvulsant use during breastfeeding, most women were taking a combination of anticonvulsants. Some other anticonvulsants (e.g., phenytoin, carbamazepine) stimulate the metabolism of other drugs including anticonvulsants, whereas others (e.g., valproic acid) inhibit the metabolism of other drugs. Therefore, the relationship of the maternal dosage to the concentration in breastmilk can be quite variable, making calculation of the weight-adjusted percentage of maternal dosage less meaningful than for other drugs in this database. Maternal Levels. Three women taking carbamazepine and phenytoin for epilepsy had carbamazepine and its epoxide metabolite measured in breastmilk. One woman receiving 6 mg/kg daily had carbamazepine milk levels of 1.8, 1.3 and 1.8 mg/L and epoxide metabolite levels of 0.7, 0.5 and 1.1 mg/L on days 2, 3 and 30 postpartum, respectively. A second woman taking carbamazepine 5.8 mg/kg daily had milk carbamazepine levels of 1.5 and 1.8 mg/L and epoxide metabolite levels of 0.7 and 0.9 mg/L at 3 and 5 weeks postpartum, respectively. The third woman taking carbamazepine 7.3 mg/kg daily had a carbamazepine milk level of 1.5 mg/L and epoxide metabolite level of 0.5 mg/L at 3 weeks postpartum.[ 4 , 5 ] Three carbamazepine breastmilk levels were measured between days 3 and 32 postpartum at unstated times after the dose in an unstated number of women who were taking carbamazepine and other anticonvulsants in unstated dosages. Carbamazepine milk levels averaged 1.9 mg/L (range 0.8 to 3.8 mg/L), while maternal serum levels averaged 4.3 mg/L.[ 6 ] An epileptic woman was taking carbamazepine 1 gram daily and primidone 1 gram daily during pregnancy and postpartum. At 5 weeks postpartum, a milk sample was measured. The milk fat contained 1.4 mg/L while the skimmed portion contained 2.3 mg/L of carbamazepine.[ 7 ] Four mothers taking carbamazepine monotherapy in an average dosage of 10.95 mg/kg daily had average milk levels of 1.78 mg/L
Alternatives LactMed lists
Source: NIH LactMed (National Library of Medicine).
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.