Imatinib use while Breastfeeding
Drugs containing Imatinib: Gleevec
Imatinib Levels and Effects while Breastfeeding
Summary of Use during Lactation
Limited information indicates that maternal doses of imatinib up to 400 mg daily produce low levels in milk. Although a few breastfed infants apparently experienced no adverse effects during maternal use of imatinib, no long-term data are available. Until more data are available, imatinib should be used only with careful monitoring during breastfeeding. Avoiding nursing for 8 to 9 hours after a dose would probably reduce the dosage that the infant receives. The manufacturer and some authors recommend that breastfeeding be discontinued during imatinib therapy.
Maternal Levels. A woman receiving oral imatinib 400 mg daily for chronic myeloid leukemia breastfed her infant. During week 4 postpartum, serum and milk levels of imatinib and its active metabolite (CGP 74588) were measured before and at several times during the 9 hours after the dose. The highest concentrations of imatinib and its metabolite were at 2 and 4 hours after the dose. Peak concentrations of imatinib ranged between 1.1 and 1.4 mg/L and were 0.8 mg/L for the metabolite. The concentrations of both were 25 to 50% lower 9 hours after the dose. Milk and serum levels were also measured during the second month of breastfeeding with similar results (details not reported). Using these data, the estimated maximum dosage of the drug and metabolite that a fully breastfed infant would receive is 0.3 mg/kg daily or 4.5% of the maternal weight-adjusted dosage.
A woman who was 7 days postpartum and had been taking imatinib 400 mg daily since the middle of her pregnancy had a single milk sample analyzed for the drug an its metabolite. Imatinib concentration 15 hours after a dose was 596 mcg/L and CGP 74588 was 1513 mcg/L. The authors estimated that a fully breastfed infant would receive between 1.2 and 2 mg of the drug and metabolite daily with this maternal dose.
A woman who took imatinib 400 mg daily during pregnancy and postpartum delivered a normal infant, but did not breastfeed. Breastmilk imatinib concentrations were measured on the 7th, 14th, 15th and 16th days postpartum at times ranging from 10 to 16 hours after the previous dose. Breastmilk concentrations ranged between 1.4 and 2.6 mg/L.
A woman with chronic myeloid leukemia was begun on imatinib 400 mg daily immediately after delivery. She did not breastfeed, but 5 breastmilk samples were obtained over the 7 days after the first dose, on days 1, 2, 3 and 7 postpartum, apparently 3 hours after the daily doses (exact times not stated). Imatinib milk levels were about half of maternal plasma levels and ranged from 151 to 1153 mcg/L. Milk levels of the metabolite, N-desmethylimatinib were about 3 times those in maternal plasma and ranged from 409 to 1052 mcg/L.
A woman received imatinib 400 mg daily beginning in week 30 of pregnancy. Colostrum and milk samples obtained during the first 5 days postpartum contained an average of 0.233 mg/L of imatinib and 0.529 mg/L of n-desmethylimatinib, the active metabolite. The authors estimated that an exclusively breastfed infant would ingest a mean of 0.12 mg/kg daily of the active drug (imatinib plus metabolite). This would be approximately 1.8% of the weight-adjusted maternal dosage.
Infant Levels. Relevant published information was not found as of the revision date.
Effects in Breastfed Infants
A woman receiving oral imatinib 400 mg daily for chronic myeloid leukemia breastfed her infant. No adverse effects were noted in the infant during the first 2 months of nursing.
One woman with chronic myelogenous leukemia received imatinib 400 mg daily throughout pregnancy and during breastfeeding (extent not stated) for nearly 6 months postpartum. Her infant reportedly grew and developed normally.
A woman with chronic myeloid leukemia received imatinib 400 mg daily starting at week 8 of pregnancy and continuing throughout 8 months of breastfeeding (extent not stated). The infant was healthy, but an atrial septal defect was repaired at 30 months of age. It was thought to be unrelated to imatinib therapy.
Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.
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Protein Kinase Inhibitors
Signal Transduction Inhibitors
Tyrosine Kinase Inhibitors
LactMed Record Number
Last Revision Date
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