No announcement yet.

Femara and breastfeeding

  • Filter
  • Time
  • Show
Clear All
new posts

  • Femara and breastfeeding

    Physician knew breastfeeding 12 month old and prescribed femara x5 days for fertility. Took medication not realizing contraindicated whole breast feeding days 3-7 of cycle now day 12. Should I stop breast feeding at this point? Any case reports of this causing issues or is it all theoretical?

  • #2

    This is my take on Femara (Letrozole). It has a long half life and would take about 10 days or more to rid from your blood.

    I'd withhold breastfeeding for at least 10 days.

    Letrozole is a non-competitive inhibitor of estrogen synthesis, and it is used for the treatment of estrogen-dependent tumors, particularly breast cancer and sometime for the inducing ovulation in infertile women. Letrozole's terminal elimination half-life is about two days and steady-state plasma concentration after daily 2.5 mg dosing is reached in two to six weeks.[1] It has a high volume of distribution and is generally used for long periods. It is well absorbed orally. No data are available on its transfer to human milk but one should expect the levels are low.

    However, this product works irreversibly and any present in milk could potentially suppress estrogen levels in a breastfed infant. The transfer of small amounts of this agent to an infant could seriously impair bone growth or sexual development of an infant and for this reason it is probably somewhat hazardous to use in a breastfeeding mother. It has a very long half-life which is concerning in a breastfed infant and could lead to higher plasma levels over time. It is not advisable to breastfeed an infant while consuming this product. Discontinue breastfeeding while taking this product or for a period of ten days following its discontinuation.

    Dr. Hale


    • #3
      So if I took it and kept breastfeeding while taking it (which I did) when you say irreversible does that mean it’s going to suppress estrogen levels impairing bone growth and sexual development forever or just the 3 weeks he’s accidentally exposed? Is there any testing I should seek on him currently


      • #4
        AK12: These are "theoretical" risks, we don't know if he levels in milk are high enough to produce a "clinical" effect on the infant, but it's certainly possible.

        As for that, it's NOT permanent, only while on the medication.

        Dr. Hale


        • #5
          Hi AK12 and Dr Hale, I’m in a similar situation, accidentally feeding a 20 month old after taking 2.5mg Letrozole. I only fed her twice (once a day over the first two days, a couple minutes each time) before realising, calling my dr, and then stopped. I’ve barely any milk left so the amount consumed at this point is very minimal.

          Still I’m horribly worried, obviously. AK12 have you received any advice on testing or had any further developments? Dr Hale, by when might any possible developmental impact be evident?

          Thank you both.