Is Cladribine safe while breastfeeding?
Here is what LactMed, the Drugs and Lactation Database published by the U.S. National Institute of Child Health and Human Development (NICHD), reports about Cladribine. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
The amount of cladribine in milk is low with oral doses of 10 to 20 mg daily used in multiple sclerosis. Data in one patient indicates that the drug is rapidly eliminated over 24 hours and undetectable at 48 hours after a dose. Manufacturers recommend a 7-day (Europe) or 10-day (US) breastfeeding abstinence period after a dose. Chemotherapy may adversely affect the normal microbiome and chemical makeup of breastmilk.[1] Women who receive chemotherapy during pregnancy are more likely to have difficulty nursing their infant.[2]
Effects on the breastfed infant
Relevant published information was not found as of the revision date.
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
Maternal Levels. A woman with multiple sclerosis who was 4 months postpartum began cladribine. In her second course of therapy, 5 weeks after the first course, she received 20 mg cladribine once daily by mouth on days 1 to 3 and 10 mg on days 4 and 5. On day 3, the patient collected samples at 0, 1, 2, 4, 6, 8, 12, and 24 hours after a 20 mg dose. The highest milk level was 281 mcg/L at 1 hour after the dose. Levels declined rapidly over 12 to 24 hours, to undetectable (<1.5 mcg/L) levels at 48 hours and beyond. The average milk level was 44 mcg/L over the 24 hour period. The authors calculated that a fully breastfed infant would receive a dose of 6.6 mcg/kg daily, which corresponds to a weight-adjusted dose of 3.1% of the maternal dose.[3] A further analysis of two patients taking cladribine for multiple sclerosis found relative infant dosages of 2.99% with a 10 mg daily dosage and 4.73% with a 20 mg daily dosage. Peak milk concentrations were seen at 1 and 2 hours after the dose, respectively.[4]
Infant Levels. Relevant published information was not found as of the revision date.
Alternatives LactMed lists
“No published information” means the studies do not exist yet — not that Cladribine is known to be harmful, and not that it is known to be safe. Your prescriber or pharmacist can weigh your baby's age and whether a better-studied alternative would do the same job. Worth asking before stopping a medicine you need.
Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Cladribine” (LM1234). LactMed on NCBI Bookshelf. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.