Can you take colistimethate while breastfeeding?
What LactMed says
The National Library of Medicine’s own summary, quoted in full. We do not write a verdict of our own on this question, and we do not compress theirs into a label.
Limited data indicate that colistin is minimally excreted into breastmilk following intramuscular administration of colistimethate. Because colistin is poorly absorbed orally, it is unlikely to be absorbed in appreciable amounts by the infant or adversely affect the breastfed infant. However, no studies have evaluated serum levels or adverse effects in breastfed infants whose mothers were receiving colistimethate. Breastfeeding is acceptable with the use of inhaled colistin or colistimethate.
Quoted from Colistimethate — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised November 15, 2024.
What LactMed would consider instead
LactMed ends this record by naming the drugs it would consider in place of colistimethate. Whether any of them fits depends on what you are treating — this is the database’s list, not a recommendation from us.
- Amikacin
- Gentamicin
- Imipenem and Cilastatin
- Tobramycin
How much colistimethate gets into breastmilk
Maternal Levels. A single dose of colistimethate equal to 33 mg of colistin was given intramuscularly to 9 women and milk levels were measured once in each woman over the next 3 hours. Milk concentrations were 740 mcg/L at 1 hour (n = 1), 760 mcg/L at 2 hours (n = 3) and 140 mcg/L at 3 hours (n = 5) after the dose. Another 20 women were given single intramuscular doses equivalent to 66 mg of colistin. Milk concentrations averaged 500 mcg/L (range 160 to 1100 mcg/L) at 1 hour after the dose, and 789 mcg/L at 2 hours after the dose (range 0 to 2100 mcg/L).
Colistimethate was given to 15 women intramuscularly on day 5 postpartum in a dose equivalent to 66 mg of colistin. After 2 doses, the average peak level was 165 mcg/L and trough was 50 mcg/L. Another 5 women were given a dose equivalent to 132 mg of colistin intramuscularly on day 5 postpartum. After 2 doses, the average peak level was 215 mcg/L and trough was 50 mcg/L. With both doses, peak milk levels occurred 5 hours after the dose.
Infant Levels. Relevant published information was not found as of the revision date.
What has been seen in breastfed infants
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.
Frequently asked questions
Can you take colistimethate while breastfeeding?
Limited data indicate that colistin is minimally excreted into breastmilk following intramuscular administration of colistimethate. The full record is quoted on this page, and the decision is one to make with the person who prescribed it — LactMed itself states it is not a substitute for professional judgement.
What can I take instead of colistimethate while breastfeeding?
LactMed lists Amikacin, Gentamicin, Imipenem and Cilastatin, Tobramycin as alternate drugs to consider. That is the database's own list for this drug — whether any of them suits you depends on what you are treating.
Does colistimethate pass into breastmilk?
LactMed's measured drug levels for colistimethate are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking colistimethate?
LactMed does not frame its records that way — it reports measured drug levels in milk and what has been observed in breastfed infants, which is what this page quotes. "Pump and dump" advice for a specific drug and dose should come from your clinician or a pharmacist, not from a general rule.
More on colistimethate
LactMed states that the information it presents is not a substitute for professional judgement, and that you should consult your healthcare provider for breastfeeding advice related to your particular situation. Nothing on this page is medical advice.